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Batteries and Crankinig Amps

Discussion in 'Truck Talk' started by Broompilot, Oct 30, 2007.

  1. Broompilot

    Broompilot New Recruit

    The higher the Cold Cranking Amps the better?

    Conversation I listened to on Nemo:

    The lower the Cold Amps the thicker the steel plates inside the same size square box of plastic, thus they take more of a beating without breaking or loosinig power. Negative not as powerfull but life of the battery will be much longer at least a year for a life of three years vs two or maybee one.

    Higher Cold Amps, lots of power but due to the thin plates they are prone to breaking and everytime you use a heavy load on them Microwave etc.. they chip and those chips fall to the bottom much faster than the thicker lower Cold Amp batteries. Also when on very rough roads and beating and banging they can also break the plates causing premature death.

    Either way I have seen those units in the truck stops that shows when your batteries are getting to low to start the truck if you run excessories in the truck you may want to buy one. (My truck has a warning system built in VERY NICE) it has already saved me once.

    I thought this would be helpfull to some of ya's.
  2. Tennesseahawk

    Tennesseahawk Seasoned Expediter

    Where did you see this unit? And how much are we talking?

    -True independence can only be gained if you're trully independant.
  3. layoutshooter

    layoutshooter New Recruit

    Hey Broom, I don't know who Nemo is, should I? In any case, his idea of how batteries are constructed is missing a bit.

    Battery plates are made of lead paste, not steel.
    Thickness in itself does not determine CCA etc.

    Thicker plates are normally found on marine batteries vx. automotive due the the heavy pounding they encounter on the water. Way more than we hammer ours.

    Deep cycle plates should be made out of alpha partical paste. Low CCA's, highter storage capacity, longer discharge slower recharge.

    Starting batteries should be made out of beta partical paste. Hi CCA, fast discharge and fast recovery.

    Using a starter in a deep cycle position will ruin it quicly and visa versa.

    Most so called deep cycle batteries are a 50/50 mix of alpha/beta paste. Trojan makes a true deep cycle battery that is 90/10 alpha/beta. I would imagine there are a few others with the higher alpha paste but I am not aware of them.

    There are many so called duel purpose batteries but as in most things they don't do much of anything right.

    One exception to all of this, high quality AGM batteries. They are a true lead acid dry battery. They have very thin plates with fiberglass mats soaking in electrolite in between them. They are then put into the case very tight under pressure to give the plates greater strength than all other batteries. They will also function well in either a starting or deep cycle application.

    I am familure with the AGM's made by Duel-Pro. The Lightning series. I used to sell them when I was a Product Specialist with Cabela's. We tested them in extreme cold, starting and deep cycle and the performed perfect. Mine lasted 6 years of hard use, all aplications and was never brought inside over the winter.

    I am also looking at Oddessy batteries. They are a high quality AGM and, as per thier tech guy, have a full 4 year replacement warrenty. The warrenty is even covered for commercial vehicals. They have a life span under normal condintions of 6-8 years and a 2 year discharge rate if not used. Those figures are true of most hight quality AGM's.

    Only down side is the price, 2-3 times higher than a flooded cell battery. BUT, if you don't have to change them but every 4 years, they work better in extreme temps etc. Might be worth it. I might change to the Oddessy when mine I have now fail.

    I hope I did not step on Nemo's or anyone elses toes on this. I sold batteries for 6 years, 4 at Cabela's and 2 at Gander Mountian. At both places I had to spend several hours every 6 months learning battery technology terms etc. Ruining a ton of cotton jeans until one tech rep from Duel-Pro taught me to wear poly-pants. The acid will not harm them.

    Hope this helps everyone. I don't know much about trucks yet but I learn more everyday reading in here. Nice to be able to add on a subject that I do know a little about. That, as far as trucking goes, is about as much as I can help. Now, any questions about fishing rod construction or fish finders? HEHEHE Layoutshooter
  4. Turtle

    Turtle Administrator Staff Member

    A decent one is gonna cost around $30. It's a Low Voltage Alarm, and monitors the battery's voltage and squeals (or winks) at you when the battery voltage is too low. The problem is how "too low" gets defined.

    Most low voltage alarms will go off on you when the voltage gets too low to run inverters and other appliances. Same as an inverter with a low voltage disconnect that powers off when the voltage gets too low to power stuff, usually well under 12 volts, most often it's around the 10.8 volts mark.

    The way batteries work, the way that lead acid batteries generate electricity is through a process called double sulfate chemical reaction. Battery plates are made of lead plates that is more of a lead grid than a plate, and acts and looks more like a sponge. Many holes are in the plate, which gives it a much higher surface area than plain solid plates, just like a sponge. The holes are filled with a lead paste made up of different formulations depending on the manufacturer, but primarily of "red lead", which is "lead tetroxide", sometimes referred to an "minimum" or simply as lead oxide. (I should note that true deep cycle batteries, like from Rolls-Surrette, Concord, Discover-Energy, Deka, etc., are not lead plate grids, or sponges, but are, in fact, solid lead plates).

    The lead and lead oxide, which are the active paste materials on the battery plate grids, react with sulfuric acid in the electrolyte to form lead sulfate. This lead sulfate is in a finely divided, amorphous form, which is easily converted back to lead, lead oxide and sulfuric acid when the battery is recharged.

    Over time, lead sulfate converts to the more stable crystalline form, coating the battery's plates. Crystalline lead sulfate does not conduct electricity and cannot be converted back into lead and lead oxide under normal charging conditions. As batteries are "cycled" through numerous discharge and charge sequences, lead sulfate that forms during normal discharge is slowly converted to a very stable crystalline form. This process is known as sulfation.

    That's why batteries wear out. Sulfation is a normal process and it cannot be avoided. It can, however, be sped up like you can't imagine.

    When you too deeply discharge a battery down below a certain voltage (see below) lead sulfate crystals rapidly form, and they are not broken back up when the battery is recharged. Instead, the crystals stick to the lead plates like iron filings on a magnet. And since lead sulfate crystals cannot conduct electricity, there ya go.

    To make matters worse, when you recharge batteries, if you don't fully recharge them (to within 90% or 95% at least), the fine amorphous lead sulfate that is not broken back down into the lead, lead oxide and sulfuric acid promptly crystallizes and sticks to whatever part of the lead plates it can find. Those that can't find an open spot on the plates, fall down and start accumulating at the bottom of the battery case. In addition, and more significantly, the plates start shedding lead (those "chips"). As the paste in the lead grids absorb the sulfate from the acid during a discharge, and as they give up the sulfate during charging, the plates change size a little, bulging and shrinking as they go. With each discharge and recharge, a little lead paste is given off the plates. When thin plates are hit with a very high amp draw, like with a microwave, for any kind of sustained period, they must give up a lot of sulfate in short order, and therefor shrink very fast, and give up a lot of lead paste very fast. (And that's why starter batteries cannot handle deep cycle applications.) Once the accumulation reaches the lead plates, the cells are shorted out, dead. Time for a new battery.

    So, when your low voltage alarm goes off when the batteries are too low, it's almost always when the batteries are way too low, and sulfation has already begun. Then, when you fire up the engine or APU to recharge batteries, and you run it for 15 minutes or an hour or two, that's not nearly long enough to recharge the batteries, and sulfation relentlessly continues.

    And it's a vicious cycle. Once sulfation begins, it feeds on itself. That's why batteries die in a year. Or more accurately, that's how their owners killed them.

    With traditional wet batteries that boil and you need to add distilled water to them periodically, with those you can force something called an "equalization" charge that purposefully charges the batteries at a higher voltage to break up the sulfation and turn it back into lead, lead oxide and sulfuric acid. Can't do that with maintenance free or any type of sealed battery, though, so don't try unless the manufacturer specifically says you can.

    A battery is 100% fully charged at 12.7 volts.
    95% - 12.64
    90% - 12.58
    85% - 12.52
    80% - 12.46

    Sulfation Begins
    75% - 12.40
    70% - 12.36
    65% - 12.32
    60% - 12.28
    55% - 12.24

    Battery Damage Begins
    50% - 12.20
    40% - 12.12
    30% - 12.04
    20% - 11.98
    10% - 11.94

    As you can see from the table above (which is for AGM, gel and maintenance-free batteries, traditional wet cell voltage states of charge are slightly different), when low voltage alarms go off at 12 volts and lower, your batteries are well on their way to an early death. And if you've got multiple batteries, don't worry, they'll all go down together. Sulfation is ruthless.

    Ideally, to prevent sulfation from even happening, and to make your batteries last for many, many years, you should never draw them down below 80% DoD (Depth of Discharge), and then fully recharge them. If you do that, then batteries that are designed to last for perhaps 5 years will easily last 10 or 12, maybe 15 years. But, in most cases, that's not practical. You'd need 10 times the batteries.

    So, the best compromise for long battery life versus cost and weight issues is the 50% DoD mark. If you never discharge down deeper than that, and if you always fully recharge the batteries, they will last several years. Good deep cycle batteries will last 5-8 years if they are never discharged down below 50%. Whatever your amp hour requirements are, you need twice that many batteries. Then, you'll always be at 50% or better, and all of the batteries will last a really long time.

    As for the discussion of high CCA versus low CCA and plate thickness and thin plates cracking when bumping down the road, that's largely inaccurate, and very misleading. Thick or thin, doesn't matter, sulfation is what cracks the plates. As the crystalline lead sulfate builds up it puts pressure on the plates, as well as on the battery case itself, to the point where the case will bulge. It's the pressure that cracks the plates, not necessarily how thin they are.

    True enough, thicker plates will last longer and won't crack as easily when they are sulfated, but that whole thick-plate, thin-plate discussion is based on the assumption that the battery owner is not going to take good care of the batteries in the first place. It's more like, "If you're going to buy batteries and then kill them, you might as well buy batteries with thicker plates so they'll last a little bit longer before they're dead."

    A lot of that comes from buying "truck" batteries, which are not designed for deep cycle applications, and then running an inverter off of them. As for thick plates not having as many CCA, that's simply not true. An 8D battery has some of the thickest lead plates of any 12 volt battery, and they usually have more than 1300 CCA. It's because 8D batteries are designed to start very large boat engines, like on a 60 foot yacht. But 8D batteries (and their 4D cousins, 1100 CCA) work extremely well in deep cycle applications, as well. 8D batteries have 255 amp hours and 4D batteries have 220 amp hours.

    Golf cart batteries, on the other hand, have much thicker (and much taller) plates than do 8D or 4D batteries, and most have 220 amp hours, same as a 4D battery. But, a golf cart battery may only have 700 CCA, significantly less than the 4D battery. It's because that battery is designed strictly for deep cycle operations, and has more actual usable reserve time than a 220 amp hour 4D battery will. It's not made for starting. But just the same, it'll give enough to start most engines, especially when in a multiple battery bank.

    Incidentally, a golf cart deep cycle battery is really only a semi-deep cycle battery. Far better than a starting battery, and much better than a marine hybrid, but the plates are sponges, not solid plates. They are thicker, much thicker, which is what gives them their deep cycle properties, but they are no match for a true deep cycle solid plate battery (the Concord Lifeline golf cart sized battery is, in fact, a solid plate, however, and is why it has a significant reserve time versus other golf cart and/or 200 amp hour sponges).

    Most truck batteries are Group 31 batteries, but that's just the case size. There are Group 31 batteries that are designed for starting, some for deep cycles, and some are hybrids that will do either quite well, within certain limits. Group 31 truck batteries have some deep cycle properties, like slightly thicker plates, but they are not, and should not be used as, deep cycle batteries. (I don't understand why the truck manufacturers haven't figured this out, yet.) Small inverter loads and for relatively short duration and a truck battery will handle that kind of deep cycle application with no ill effects, provided you don't discharge the battery down more than 50% and the amp draw is minimal.

    Like, if you draw 250 watts sustained, that's drawing about 22 amps from a single 100 amp hour hybrid truck battery. A 22 amp draw is considered a deep cycle load. At 22 amps, you'll drain the battery dead in about 2.7 hours (3.8 hours for an AGM). If you have three 100 amp hour truck batteries, you'll drain it in 11 hours, or you'll be down to around 50% DoD in 5 1/2 hours.

    Batteries are rated in amp hours at the 20 hour rate, which means whatever sustained amp draw that will deplete the battery in 20 hours is how many you can draw from it for 10 hours before the battery is too deeply discharged. In the case of a 100 amp hour battery, that's 100 amp hours divided by 20 hours gives you a 5 amp draw. 5 amps for 20 hours to 100% DoD, or 5 amps for 10 hours to 50%.

    There are other factors such as battery temperature and the Peukert Effect that will increase or decrease the actual amp hours you have available depending upon battery temperature and the rate at which you draw the amps from the battery (or recharge them back into it, for that matter), but suffice it to say that cranking and hybrid batteries aren't as efficient as true deep cycle batteries. For this reason, if you're using truck batteries for your inverter loads, you should never draw a sustained load (more than 30-60 minutes) of more than the 20 hour rate draw, which for 100 amp hour batteries is 5 amps. And you should not draw from those batteries for more than 5 hours without fully recharging them.

    Now, if you have more than one battery, you can multiply everything by the number of batteries. Three 100 amp hour batteries is 300 amp hours, and you can draw a sustained 15 amps for the same 5 hours, or you can draw 5 amps for 15 hours, same thing either way (dismissing the Peukert Effect, of course), and you'll keep your batteries at 50% DoD or higher. So, if you have a microwave that's gonna draw nearly 15 amps, you can do that with at least 3 truck batteries, for a few minutes, anyway, and as long as you compensate later in time or amp draw, you should be OK.

    Know your total daily amp hour needs, or you total watt hours, and then go from there. You may need to cut back on your electrical usage, or you may need a separate house bank for your inverter loads. But you can get by with truck batteries, as long as you don't try and use them as if they were deep cycle batteries. They're not.

    Your best bet is to not try and use the battery for which is was not designed. Buy starting batteries for starting, and deep cycle batteries for inverter applications. In most cases, your truck batteries already have their hands full in just dealing with the demands of the truck.

    And, you have got to monitor the batteries to keep theme from being too deeply discharged. Best method is with a real battery monitor, like a Xantrex Battery Monitor. It will keep track of all amps in and all amps out, and will know (and tell you) when the battery is fully charged and when it's down to 50% DoD.

    Or at the very minimum, for starting batteries, anyway, and perhaps for batteries that are used for very light inverter loads, use something like a Battery Minder from UPG.

    It will monitor your battery's voltage and let you know when it's down too low, and it's one that you can manually set the low voltage setting at 12.2 volts for the trigger, and that will help prevent you from too deeply discharging the battery and keep it alive much longer. Most low voltage alarms are preset to squawk at far too low a voltage and, despite its intentions, only aids you in killing your batteries. It's $30, and is not even close, not even in the same ballpark, as a $225 Xantrex Battery Monitor...

    but it's way better than not monitoring them at all and then not being able to start your truck. :)

    Keep in mind that voltage testing a battery, at least insofar as trying to determine the actual percent state of charge, is by and large, inaccurate, as it's only good when the battery is a rest, meaning with no loads connected to the battery for at least one hour. And even then, a battery may show 12.7 volts and then as soon as a load is applied (or a load test) it may drop immediately to 11.5 volts or less, because it can't hold the charge (sulfation). Only a sustained load (Or the Xantrex) will tell you how good the battery is (how many amp hours are left in there).

    But the Battery Minder works for what it designed to do, at least better than anything I've ever seen or heard of, in that it will almost always prevent you from running your starter down to the point where it won't crank the starter motor. Don't trust high end (high dollar) deep cycle batteries to a $30 Battery Minder, because that's not what is is designed for. Use something like the Xantrex, instead.

    But for a starting battery, the Battery Minder should do you OK. Just keep the inverter loads to a minimum, and no heavy inverter draws, like with a microwave, unless you are completely aware of what you are doing. Using high amp draws, like with a microwave, dramatically speeds up sulfation on thin plates on starter and hybrid batteries. You wouldn't hook a trolling motor to a car battery, so why hook a microwave to a starting battery?

    Just a couple of quick points... (well, relatively quick)

    "Thicker plates are normally found on marine batteries vx. automotive due the the heavy pounding they encounter on the water. Way more than we hammer ours."

    Uhm, that sounds like the mantra of a bass boat salesman. :)

    There are two basic types of "marine" batteries, those designed to start the main engine, and those that are designed specifically for trolling motors. Batteries for starting your motor are called cranking batteries, and trolling batteries are called deep-cycle batteries (even though most "marine" deep cycle batteries aren't actually true deep cycle batteries. They are merely deep-er cycle batteries than are cranking batteries. Still, they work perfectly for what they are designed for, which is a trolling motor.) These cranking and deep-cycle types are distinguished in their construction by the lead plates inside the case.

    Cranking batteries have numerous thin lead plates that give better bursts of energy for a fast start. Deep-cycle batteries have fewer, thicker plates that provide better power output over a longer period of time. A marine cranking battery's plates aren't any thicker than an automotive cranking battery, boat pounding notwithstanding. With many battery manufacturers, the only difference between a marine cranking battery and an automotive battery is the terminals and the labels on the case - inside they are identical. (my sister-in-law is a big shot with Johnson Controls in San Antonio and she gave me an interesting, and eye opening tour of the battery plant where several familiar brands and types of batteries are made.)

    As for the alpha particle paste and beta particle paste, well, alpha and beta particles are more akin to cosmic rays than they are lead. :) You could call the two predominant forms of lead oxide as "alpha lead oxide" (more accurately as litharge) and "beta lead oxide" (more accurately as massicot). Litharge and massicot are the natural mineral forms of lead oxide, with massicot being the crystalline form of litharge (which is lead tetroxide, or red lead). They are used together in different ratios in the paste of the lead plates depending on if the plate is to be a negative or a positive plate, and because each form of the lead oxide has a different specific gravity, they are mixed in different concentrations in order to achieve a specific, specific gravity within the cell.

    "One exception to all of this, high quality AGM batteries. They are a true lead acid dry battery. They have very thin plates with fiberglass mats soaking in electrolyte in between them..."

    Well, I don't know that I'd call them dry. They're not wet flooded like traditional flooded batteries, where the electrolyte will slosh around in there, but the fiberglass mats are soaking in traditional wet battery acid, just the same. More accurately, they are referred to as SLA batteries (Sealed Lead Acid), and are, in fact, wet batteries.

    "They are then put into the case very tight under pressure to give the plates greater strength than all other batteries. They will also function well in either a starting or deep cycle application."

    AGM's are sealed VLRA (Valve Regulated Lead Acid) batteries, and are usually (but not always) designed for deep cycle operations. AGM batteries have some of the thickest, and quite very solid, plates in the "consumer" battery industry, with L16 (case size and configuration) batteries being the only battery that will have substantially thicker plates than a standard 12 or 6 volt AGM battery. L16 batteries, both traditional wet and AGM or gel, are more commonly referred to as floor scrubber batteries, and quite honestly blurs the line between industrial and consumer batteries as far as that goes. But for serious deep cycle application, they're hard to beat. For thicker lead plates in a true consumer application, you'll have to go with some seriously high dollar Rolls-Surrette and others of that type that are used in alternative energy off-the-grid applications. (There are some 2-volt batteries that would blow your mind. Like, 2 volts, and you need 6 of them to make a 12 volt battery, 450 pounds each, 3300 amp hours, $3,400 a pop. Thaaaat's 2700 pounds for a 12 volt AGM battery that you can draw a sustained 165 amps for 20 hours. Kewl. Wrap it up. I'll take it with me.)

    Automotive batteries have plates that are usually .040" thick or less. Most "marine" and hybrid plates will be around .06" thick.

    Most truck batteries, the 100 amp kind (Group 31, Group 27), are .06" to .08" thick.

    A typical golf cart battery's plates will be .07" to .11" thick. But they are taller than most batteries which makes a difference.

    A typical AGM plate will be .113" and the Concord AGM's are .115" (except their golf cart sized is .117").

    US Battery and Trojan wet cell L16's are .090", which is kinda wimpy, but an L16 is much taller than a regular battery.

    A Rolls-Surrette wet cell L16 and a Discover-Energy AGM L16 are both a significant .150" thick, and they are very tall batteries (16 inches plus), 6 inches or more taller than most regular batteries.

    A typical forklift battery will have plates that are .265" thick, more than 1/4". (The 2 volt battery mentioned above has .52" thick plates).

    Thicker means more reserve time, more amp hours, and can be deeply discharged at a high amp draw. You get what you pay for.

    The case of an AGM are sealed under slightly positive pressure, not to strengthen the plates, per se, but to prevent them from leaking while inverted, and internally process charging gasses (won't outgas hydrogen gas under a charge), and as a side effect, it makes the cases and everything in them less susceptible to damage from vibration and impact damage.

    If you want the best in an AGM you should pay close attention to where these are used in critical applications, like off-the-grid renewable solar and wind energy applications, seaworthy watercraft, ambulance and rescue, aircraft. People's lives depend on those brands of AGM batteries. Brands like Concord Lifeline, Concord SunXtender (same batteries as each other, just different labels and warranties), Discover-Energy (especially for an L16 AGM), Deka (often as MK, they're from East Penn Mfg). Not all AGM's are created equal. There are brand names that you may know and trust, but their AGM's just aren't up to par (Trojan comes to mind, as their AGM's aren't the same as their wet cells are, which is a shame, as their wet cells are nearly cream of the crop).

    After exhaustive research and experience (I've had a boat or two in my day) the brands I've mentioned here are the ones that I can confidently recommend. For my money, the best bang for the buck, hands down, is the Discover Energy L16 AGM (assuming that it's properly cared for, of course). After that, a close second is Concord Lifeline. Concord lifelines, even though they are deep cycle batteries, are also designed for use on large watercraft, and they make excellent cranking batteries as well as excellent deep cycle batteries. They may be the only exception to a battery that does both very well. And they handle cold cranking in extreme cold weather extraordinarily well (unlike a gel battery which is useless under 30 degrees, and equally useless when it's over 105 degrees outside, which is why gel batteries are rarely used in solar power applications, but keep them within a certain temperature range and they have some significant advantages over AGM's).

    I should note that AGM's (and gels) require some rather strict charging parameters, so make sure you know them and can live up to them before you go out and fork over big bucks for these high end batteries. (for example, AGM's will not properly charge off the Sprinter's alternator. Period. Gel batteries might but I'm not all that confident, yet. Gels are even pickier than AGM's, but in different ways.)

    Your mileage may vary.

    Slow and steady, even in expediting, wins the race - Aesop
  5. Dreamer

    Dreamer Administrator Staff Member

    Wow. Ken? Were you by any chance a technical writer in a past lifetime? LOL.

    Great post... and I think safe to say, the longest in EO history!

    That was 8 pages printed, 3975 words! I think my FINGERNAILS would have cramps if I typed that long at once. :)

    Great stuff!

    Forums Administrator

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  6. greg334

    greg334 New Recruit

    Turtle, can you summerize that? ;)

    I think the battery that everyone is talking about is made by Volvo. They (the advertisers on ch xm171) made it a point that these are duel purpose batteries for the trucker who has only one set of batteries on his truck.
  7. Moot

    Moot Expert Expediter

    Transit 350
    I run 2 deep cycle batteries in my van isolated from the main starting battery. I can't imagine operating an OTR truck without a bank of deep cycles isolated from the main batteries.

    Ken, what are some of the advantages/disadvantages of going with 6 volt batteries in series for truck applications? Do 6 volt deep cycles exist?
  8. layoutshooter

    layoutshooter New Recruit

    Several AGM batteries are classed by D.O.T. as *dry* batteries for shipping purposes, that is what I meant by *dry* batteries. It is true that all AGM are NOT created equal. THe Trojan is made in China out of low quality lead. The Duel-Pro Lightning is made in the U.S. out of 98.5% pure lead. So is the Oddessy. I have not tested the Oddessy myself, only the Lighting. Most AGM's can be place on thier sides but not upside down.

    The Concords etc are great as are the others mentioned, I am looking at the Oddessy because of the warrenty. They claim they are MIL-SPEC as well but I have not been able to confirm that.

    AGM batteries are a bit picky on charging as stated but not as bad as GEL. I would not consider a GEL battery in a truck. Layoutshooter
  9. Turtle

    Turtle Administrator Staff Member


    hehe. Yeah, I try to answer the question in the first paragraph on things like this, that way the short and sweet answer is there, and then if anyone still cares they can continue reading. :)


    Yeah, 6 volt deep cycles exist. It's the heart of most alternative energy systems. The really large installations and corporation setups (like telecommunications and CATV) may use the uber huge 2-volt cells, since those things last 20 or more years, but or most people, like those with solar panels on their roof at home, are going to go with the far cheaper 6 volt alternatives.

    Golf cart batteries are 6 volts, and because they are so widely available, and cheap, they (especially the Trojan T-105) are the most popular. You can get them at any golf cart shop.

    But, the batteries like the T-105 (which is a traditional wet cell) are really the entry level point for those with very small system. Really small meaning they work well for a 5th wheel camper, boondockers and folks like us. They just can't handle running a house in New Mexico is all, because you'd need too many of them. Plus, of the batteries of that ilk, they have a rather meager lifespan.

    But, they're about $100 each, and each is 220 amp hours. So, for a couple hundred dollars you get a 220 amp hour 12 volt battery that last longer than a regular 220 amp hour 12 volt battery. You just connect the two 6 volt batteries together to make one 12 volt battery. In larger systems they connect several to make 24 and 48 volt systems.

    For inside a living space like inside a camper, truck or van, you don't want the T-105's because they are wet cell. They'll slosh and spill, boil over when charged, and outgas enough hydrogen that a spark would make the news. You don't want that. You want AGM or gel.

    The footprint of a golf cart battery is more compact, slightly smaller than a regular battery, but it's taller by an inch or so. That means taller plates, and the plates are thicker. Taller and thicker means more amps hours, and taller means more actual, usable reserve time minutes than a 12 volt battery with the same exact amp hour rating.

    Group 27 and 31 batteries are about a foot long, where golf cart batteries are about 10" long.

    Golf cart batteries weigh about the same as a car battery (Group 27) and a truck battery (Group 31) at about 65 pounds. That means you can handle them by yourself. The same 220 amps in a 12 volt battery weighs twice as much, just the same as two of the 6 volt golf cart batteries. But you can handle them at 65 pounds at a time a lot easier than you can at 130 pound each.

    So two golf cart batteries weight the same and are nearly the same size as one 12 volt battery, and they have the same amp hours as a 12 volt battery with the same weight. So forgetting about the weight of a single 12 volt battery, why not just get 12 volt batteries instead of messing with having to connect a bunch of 6 volt batteries together? It's because the lead plates in 6 volt batteries are heavier, thicker, and taller, and will result in a longer lifespan and a disproportional amount of reserve time in comparison to a 12 volt battery. You get more bang for you buck.

    For example, Concord Lifelines (that have a 5 year warranty, BTW) has a golf cart battery (GPL-4C) that's in the golf cart footprint, but it's the same height as a regular battery (about 9 1/2 inches, give or take) and it's 66 pounds and 220 amp hours. It has a reserve time of of 492 minutes when discharged at a 25 amp draw. Two of them to make a 12 volt battery is 132 pounds, 220 amp hours, 492 minutes.

    Their GPL-4D 12 volt battery is 135 pounds, 220 amp hours, 390 minutes of reserve time.

    The taller, thicker plates give you more reserve time.

    The GPL-6C is the same size as the 4C, but it's 13 inches tall, 3 1/3 inches taller than the 4C, and it weighs in at 93 pounds. It's 300 amp hours and has 690 minutes of reserve time.

    300 amp hours is getting very close to the L16 range.

    L16 batteries is what gets used most often in alternative energy applications, in places where you need a lot of amp hours or reserve time in a compact space. They are about 11.6 inches long, about the same as a regular battery, 7 inches wide, which is smaller than 4D and 8D's but about an inch wide than Group 27 and 31 batteries. But, they are tall, nearly 17 inches tall, and taller is better when it comes to amp hours, heavy draws and deep discharges, and reserve capacity. They weight about 125 pounds. L16's have an amp hour rating of somewhere between 390 and 420 amp hours, and a reserve time of 915 minutes, give or take.

    Two L16's will weigh 250 pounds, 400 amp hours and have 915 minutes.

    That's about the same as two 12 volt 4D batteries, which will weight 270 pounds and have 440 amp hours with only 780 minutes of reserve time.

    These are serious batteries. A GPL-4D is gonna cost $450. A 6C will cost $240 (a pair at $480) and a 6D is $315 (a pair at $630). A Discover Energy L16, the 400 amp one, will cost $320 (a pair at $640), which makes it by far the most bang for he buck.

    What size you should get depends on amp hour requirements, available space, and weight issues. Most of these batteries are the same cost and have identical specs for AGM and gels, and both have their issues with charging requirements. Unless you know, for sure, that you can provide the proper charging and monitoring, you'd be nuts to lay out $600, $1200 or more for a battery bank with these batteries. They may be high end, really good batteries, but you can murder them within a year just the same as you can a bunch of $65 Wal Mart batteries.

    AGM's require a constant voltage of between 14.2-14.4 volts, but you can actually feed them as many amps as you can pump through the cables. With most batteries, you have to keep the current (amps) down to about 25% of the total amp hour capacity, otherwise they'll heat up too much when charged and boil, and the sealed, maintenance free ones will just explode when that happens. With AGM's you can over charge them, say, to 14.6 or even 15.0 volts and they'll still be OK for the most part. Once in a while you can do that, and that's important to know if your alternator's regulator isn't all that regulated.

    But with gels, they require the most strict charging parameters of any battery out there. All batteries should be temperature compensated and the voltage automatically adjusted up or down depending on the temperature of the battery. With AGM's as long as the batteries aren't in extreme temps, they will, for the most part, self regulate and be OK, as long as the voltage is at least 14.1 volts. Basically, with each 10 degree temperature differential from the baseline of 70 degrees, the voltage must be adjusted up or down a tenth (or more or less) of a volt. With AGM's a tenth of a volt here or there won't be catastrophic, it generally just means they are fully charged before yu think they are, or they aren't quite as fully charged as you think. A temperature sensing battery monitor will adjust for that and keep you informed.

    But with gels, temperature compensation is absolutely critical. With gel batteries, a single tenth of a volt too much at a given temperature will kill it dead right now. You charge a gel as follows:
    40 degrees - 14.2 to 14.5 volts
    60 degrees - 13.8 to 14.15
    70 degrees - 13.7 to 14.0
    80 degrees - 13.5 to 13.8
    90 degrees - 13.4 to 13.7

    If it's 80 degrees and you charge it at 14.1 volts, your gonna need another battery. And there's no van or truck alternator that can handle those kinds of charging requirements. That means an external, temperature compensated, programmable voltage regulator that can be programmed specifically for gel batteries. And if you've got AGM's, you really need the same type of external regulator (the alternator on a Sprinter cannot be modified to use an external regulator.)

    Gels work great on a boat, as those things are usually set up for external, programmable voltage regulation, and the alternators for boats are designed that way. But in a van or truck, not so much. Most vans and trucks, however, will handle an AGM rather well. In Europe AGM's are nearly becoming the standard for starting batteries, as well, because they crank in extreme cold conditions so well. A gel is worthless below 30 degrees. The available amps just drops off the table below that.

    If you have your battery bank inside the vehicle where the temperature is relatively constant, most vehicles will put out enough voltage to keep them properly charged. Make sure your does, though, before you go out and by AGM's. You may need to get something like a Balmar Max Charge external regulator and perhaps a Duo Charge regulator/isolator to then feed the proper voltage to the starter batteries.

    So, with all that said, 2 6 volt batteries is better than a single 12 volt battery in almost every respect. You can connect a pair of 6 volts together to make a 12 volt, and then connect another pair to make two 12 volts, which will keep the volts to 12 but double the amp hours, and then keep on adding them until you have the desired number of amp hours.

    Only you know what your daily amp hour requirements are, but for most people, I'd say that four 6-volt golf cart batteries at 440 amp hours is gonna be plenty. That gives you 220 daily amp hours before dropping the discharge below 50%. If you need more, you can go with more batteries, or go with the 6C's at 300 amp hours, and 4 of those gives you 600 amp hours. A single pair of the L16's, though, will give you 400 amp hours for about the same price as the 4C, and because of the taller plates they'll have a longer lifespan (if properly cared for, 7-10 years is likely).

    Then again, if your amp requirements are low and you don't do many heavy amp draws, four of the 12 volt Wal Mart Everstart Maxx marine batteries will give you 500 amp hours and (because of the shorter plates) about the same amount of usable reserve time as as about 350-400 amp hours of AGM deep cycle batteries. Four of those are about $280, $70 apiece. Even with those, though, use a Xantrex Battery Monitor so you don't just kill them in a year. (If you do kill them, though, they have an 18 month full replacement warranty).


    Oddessy makes some good batteries, but their strength is in motorcycle, ATV things like that. The bigger AGM's are way overpriced for what you get, IMHO. Pound for pound, size for size, you get far more reserve time with other brands than with Oddessy because the Oddessy batteries don't have the taller plates. They just aren't as much battery for your money.

    Far as I know, all AGM's are made to military specs. It was Concord, actually, that developed the AGM battery that met and helped create those specs. There's a release somewhere that details it all, and it's a neat read regardless of which brand someone might choose, just to see what the specs are (it's amazing). But I can't find it now.

    The Dual Pro batteries are fine for what they are designed for, which is marine applications, but they are all sponge batteries and not true deep cycle solid plates. They are the semi-deep cycles batteries, better than marine, but not quite up to a solid plate battery. They may or may nor work for you, just depends on what you need, price versus performance versus lifespan versus overall cost. I've got two of those on my runabout, actually. I do like them, for what they are designed to do, and they work well.

    Slow and steady, even in expediting, wins the race - Aesop
  10. layoutshooter

    layoutshooter New Recruit

    Thanks for the info. I got great service out of my Dual-Pro. I sold a ton of the and never had a complaint. I once put a pair on a fire engine. They had been going through a set of normal flooded cell every six months. The Dual-Pro set lasted 3 years. Do any of the other batteries come with the warrenty that Oddessy has? 4 year full replacement. That is why I am looking so hard at them. Layoutshooter
  11. Turtle

    Turtle Administrator Staff Member

    Layoutshooter, while the warranty is important, proper charging and proper monitoring is even more important. Proper charging and monitoring will make any battery far outlast its warranty.

    Rather than rely on a warranty, it's best to take care of the batteries in the first place and use the warranty not because the batteries have been killed before their time, but only if there is truly a defect in materials or workmanship. Here's why... One, battery manufacturers like Odysesy (or Hawker batteries, or more accurately EnerSys Energy Products, which is the parent company and the actual manufacturer) know when a battery has been abused. Too deeply discharged, chronically undercharged, etc.

    The Odyssey warranty states the 4 year warranty period, OR, 400 cycles of 80% DoD, whichever occurs first. They also state that the warranty is void if the battery is allowed to be drained by a parasitic load (a small, constant, 24/7 drain on the battery). These provisions are about the same with all deep cycle battery manufacturers.

    OK, on the parasitic load, an inverter connected to the battery, when turned on, even with nothing plugged into it being turned on, has a no-load draw of somewhere between .1 amp and 1.0 amps (some more, some less). That's a parasitic load that qualifies to void the warranty (if the batteries are ever drained down as far as 80% DoD). I have a small AA battery charger always plugged in (to keep batteries freshly charged for the camera), as well as one of those air ionizers. Combined they draw a fraction of an amp, though, but it's a constant, relentless, parasitic load.

    Everyone's requirements are different. Some people simply flip the inverter off when not using any of the appliances connected to it, thereby not drawing any power from the battery when not using inverter appliances. Oh, if only I were one of those people. But I've got a fridge that needs to be always plugged in (even though it doesn't actually run, and draw current, 24/7, as the compressor cycles on and off). But the inverter needs to be on when the fridge needs it, so there's the parasitic load.

    OK, now, the 400 cycles at 80% DoD. If you deep cycle the batteries down to 80% DoD, then 400 cycles is all you're gonna get (it's actually 600-800 with gels at 80% DoD, which is a huge advantage over AGM's and wets). The reason they only warranty it for 400 cycles at 80% DoD is because when you get down that low, anywhere below 50% DoD, sulfation causes an early death of the batteries. If you discharge the batteries that low on a daily or semi-daily basis, you're looking at not much more than a year or a year and a half of battery life.

    On the other hand, if you use a battery monitor, and you never discharge them below 50% DoD, and use the monitor to make sure they are actually fully recharged each time you charge them, the same batteries will give you somewhere between 800-1000 cycles. Now you're looking at 3-4 years of life (partly due to not too deeply discharging them, and partly due to the Peukert Effect).

    So, if you have 200 daily amp hours of requirements, and you have 400 amp hours worth of batteries, 50% DoD is likely all you'll ever discharge them to, and they will last a long time. On the other hand, if you have the same 200 amp hours of requirements and you have more than double the battery capacity, like 600 amp hours, now you're drawing the batteries down to probably no more than 30% or 35% DoD. That combined with the Peukert Effect of giving you actually more available amp hours than the batteries are rated for (they're rated at the 20 hour rate) and the same batteries will give you between 1200-1700 cycles, and will last 5-8 years, depending on the quality of the battery to begin with.

    The same kinds of savings can be achieved to a degree if you are anal about your amp draws and keep the parasitic loads to a minimum and don't use more than you absolutely have to, but only you know your habits and how you live. I'm anal about a lot of things, but I'm rather somewhat wasteful when it comes to electricity in this van. Mainly, the electricity is there when I need it, so I don't worry about it much. I've got 4 florescent lights in here that draw 8 watts (about .7 amps DC) each but I only burn one at a time mostly. I have 4 in case I need them. But the one I burn, I'm sure I burn it for more hours a day than I need. I don't need two external hard drives for my laptop, but they sure are nice (a 160gig and a 320 gig My Book from Western Digital). (They power down when not in use, tho, which is good cause they aren't portable, they are just external. Don't really want the drives powered up when I'm bouncing down the road.) I have the AA battery charger, couple of other small things. I leave the printer on more than I should, but it does have its Sleep Mode that draws almost nothing. But almost nothing several times over add up to something. I probably have 2 or 3 amps of constantly, relentless, parasitic loads in here. Wasteful, yes.

    A pair of 6 volt batteries will cost a little more than a single 12 volt battery of the same capacity, but the 6 volts will last longer, so it's a wash. If you need, for example, two 6 volt batteries at 220 amp hours to satisfy your daily 50% DoD requirements, those batteries will cost about $500 for the pair. If you don't monitor them and if you discharge them too deeply too often, and don't fully recharge them often enough, they'll be dead within 18 month at most. You're looking at $330 a year for batteries (removing free replacement warranties, for the moment).

    If you monitor them with a battery monitor and take care of them, (when I say take care of them, the battery monitor really takes care of them, for the most part. It's not like you are franticly worrying about baby sitting your batteries 24/7 hehe), they will last maybe 4 years at 50% DoD, and now the same $500 costs you about $125 a year.

    Instead of twice the battery capacity that you need, if you go with four of the pairs of 6 volts instead of one pair, giving you 440 amp hours, you're looking at about $1000 for the batteries, but that many amp hours of capacity means you'll actually have more available amp hours (Peukert Effect). It'll also cover you as you add more appliances down the road and you daily amp hour requirement subtly change on you (kind of like how your empty weight ticket will grow on you over time). It's much better to get more batteries than you need up front than it is to add new batteries to old batteries later. The old batteries will just wear out the new batteries, make them work twice as hard as they should.

    But if you go with 440 amps hours and $1000 worth of batteries, even though your daily requirements are in the 100 amp hour range, when you do that you'll be drawing the batteries down to 25% DoD and they will last many years, easily 8-10. If you figure only 8 years, the extra $500 for the extra batteries still costs it out to just $125 a year for batteries, but it will actually be less than that, probably about $100 or less, because they will recharge faster when they aren't discharged as deep (again, the Peukert Effect), so they'll cost less to operate.

    In other words, the more batteries you have, the less cost per amp hour used over the life of the battery. That assumes monitoring and proper charging, of course.

    This kind of setup isn't for everyone, as you may be perfectly well off with the cheap Wal Mart batteries. They have an 18 month full replacement warranty. I really shouldn't keep calling them cheap, because they are actually quality batteries made by Exide. The reason they can warranty and replace them for 18 months is because when people kill them, more than 90% of the battery's innards can be recycled and reused in new batteries (something that cannot be done so easily with solid lead plates in a true deep cycle battery, BTW).

    So back to warranties. Odyssey may have a 4 year warranty, but you may have to prove to them how you monitored them and that you haven't too deeply discharged them more than the 400 cycles they are warranted for. They can tell how many 80% DoD cycles and chronic undercharging a battery has been through simply by the manufacture date and the amount of sulfation a battery has within it. SO you may or may not get that 4 year warranty.

    Concord makes both the Lifeline and SunXtender line of batteries. The Lifeline is the premium line and the SunXtender is made and marketted mainly for photovoltaic (solar energy), wind and other renewable energy applications. Most of the Lifelines have the SAE or the dual type marine terminals, whereas most of the SunXtender batteries have the bolt-only type of terminals. For this reason, there are some internal difference in these two types of batteries, but other than that, the batteries are interchangeable and are identical. The Lifelines have a 5 year warranty and the SunXtenders have a 1 year warranty.

    The Lifelines have a 1 year warranty when used in photovoltaic or other application other than marine or RV. The reason for that is that more often than not, in a photovoltaic application the battery bank, which is usually large enough to handle several days between recharging, like 4-8 days worth due to varying degrees of available sunlight, the batteries are left unattended out in some non-climate controlled shed in the middle of a field in the middle of New Mexico or Arizona where the temps can reach 140 inside there in the summer, and below freezing in the winter. Even though the SunXtenders and the Lifelines are identical batteries, the 5 year warranty of the Lifelines is something you pay for. They are more expensive than the SunXtenders, even though they are the same battery in every important respect. The only difference is the warranty that you pay for in the Lifeline series.

    At some places, though, the price difference isn't very much. For example, at (cheapest place I know of for these kinds of high end batteries) the SunXtender PVX-2240T, 6 volts, 220 amp hours, is $244.96 each. The same Lifeline battery, the CPL-4C, is $241.97. So in that case it's actually cheaper to buy the better Lifeline warranty. :) But at most places the Lifelines are about $25 more than the SunXtender equivalents.

    In photovoltaics where you are off the grid (and are even more anal about your electricity usage) you may need 24 of the 300 amp hour, 6 volt GPL-6C (or SunXtender equivalent) in order to have the 3600 amp hours needed for a 5 day reserve time, and that's figuring at drawing them down to 80% DoD. In those situations, you need to figure from 3-5 days because it might be that long before the sun comes out long enough to fully recharge the batteries from solar panels. In those kinds of really large battery banks, one, L16's would be used, and you'd need 18 of those, but in any case, a manufacturer isn't likely to warranty that large of a battery bank seeing how as just one battery going bad will bring all of them down at once (there are ways to wire the bank together so that doesn't happen, tho).

    In any case, the warranty is less important than how to take care of them. Whether it's one year or four or five, a defective battery is likely going to show itself within a year, even if you take perfect care of it. If you don't take care of it, and you kill it, you may or may not be able to collect under the warranty. It all depends on how the manufacturer wants to deal with how they died. So don't get too caught up in the warranty unless you are fully prepared to properly care for them (or, in the case of Wal Mart batteries, killing them early is perfectly fine cause they'll replace them, anyway.)

    At the moment I have three of those Wal Mart batteries in this Sprinter, soon to be 6 of them. After much frustrating and exhaustive research, I have found out that the Bosch alternator on the Sprinter cannot be modified to use an external regulator, and therefor cannot properly charge AGM or gel batteries. Apparently, the computer on the Sprinter is just too tightly integrated into the signals coming from and going to the alternator's internal regulator. When you mess with that, or replace the alternator with one that can be externally regulated (which is no big deal on almost any other vehicle), the computer thinks something is wrong with the alternator, and the electrical systems on the Sprinter may or may not work properly. Things might not work, wires might get fried, all sorts of things can (and have) happened to Sprinters when the alternator has been altered.

    Because of the ever increasing variety of electrical demands placed on vehicles, not only are the computers being more and more integrated into the charging and electrical systems, but we're now starting to see things like 36-volt electrical systems in some vehicles. The Sprinter, just for one example of how things are changing, is one where if you install a replacement tail light and you insert the bulb in upside down, the vehicle won't start. The computer knows it's upside down. The tail light has a dual filament and if it's installed upside down then your brake lights will always be on, until you depress the brake pedal, which will then turn them off. They don't want you driving around with reverse-operating brake lights, therefore the thing won't start up if you install the bulb backwards. I can only imagine some of the problems that could arise if the regulator was bypassed in favor of an external one that was programmed for a different voltage and charging scheme.

    The only viable option for AGM's or gels on a Sprinter, to ensure they are properly charged, is to either plug into shore power on a regular basis (nearly daily, as with an RV conversion, or at the very least once or twice a week) and charge them with a programmable, regulated charger, or do the same with a generator hooked to a charger. Otherwise, it's cheap Wal Mart Everstart Maxx marine batteries at 125 amp hours each, until I can find something in a taller golf cart type footprint that have the same basic charging requirements as automotive or marine maintenance free batteries.

    Slow and steady, even in expediting, wins the race - Aesop
  12. layoutshooter

    layoutshooter New Recruit

    I am running a Freightliner M 112 2006. I have not, as yet, set up a monitoring system, that will be put in place whenever I buy whatever new batteries when I replace what I have. I have a 6 battery system. Battery isolators, shut off switches etc. It is set up to start the APU when the batteries get down. It does work, I tested it when I was home last time.

    I am well aware of the need for proper conditioning and charging of batteries. I will be looking for a charger/chargers for use when I am home or where ever I have shore power. I have not been in the battery/charger business for over two years now and will have to do some homework on chargers. I am most familar with Pro-Mariner chargers. Very good chargers but I am not sure how they will work in my application. Having six batteries makes it a bit more interesting. I have always had every battery conectted to the charger. Dual-Pro and Pro-Mariner have chargers with multilple leads. As do many others. Have to research on how I am going to do all six.

    I seldom if ever let my battiers run down to a 80% That is how I got the 5 years out of my Lightning battery. Ran it very hard but kept it up.

    I have time to work on this, the batteries I have so no signs of having any problems. AGM's might not be necesary. We shall see.

    Time for me to go back to school and get caught up on my learning. As with most people I want perfect performance from my toys. I am willing to spend more than what might be needed to insure realiabilty. Not many things sucks more than dead batteries.

  13. Broompilot

    Broompilot New Recruit

    OK I knew it was lead, but metal what ever like I am gona research inside with the liquid (acid) I presume.

    Articles on this post just to long, it is easier just to determine the bad one and replace than spend a physics class reading this much although I did.

    Last truck had low power batteries, replaced only after two and half years, ran them dead about a dozen times. They still always took a jump or a recharge.
  14. cheri1122

    cheri1122 Expert Expediter

    Turtle, that was impressive - my eyes are crossed, my brain is numb, but I do appreciate the expertise you've shared. I now have a question:
    My truck has 8 batteries: a starter, a bank of six in an outside box, and one on the generator. Would I need 3 monitors to keep an eye on, as they're in 3 different locations?
    PS If you ever put out a Cliffs Notes of the info, let me know, ok?
  15. Turtle

    Turtle Administrator Staff Member

    Cliff Notes:
    Learn the difference between starting batteries, marine deep cycle batteries, and true deep cycle batteries. Each type is designed for a specific application, and all will perform equally badly when used in an application for which they are not designed.

    Don't discharge your batteries to the point of lights dimming, fan motors slowing, and inverters whining (80%-90% Depth of Discharge). Recommended level is 50% Depth of Discharge. When you recharge the batteries always insure that they are fully (at least 95%) recharged before ending the charging process. When you discharge too deeply and fail to full recharge, you are drastically reducing the lifespan of the batteries.

    If you are unable to ensure a full recharge on a regular basis, no less than three weeks should pass before hooking to shore power and fully charging the batteries with a three-stage battery charger that is designed for your battery type.

    A battery monitor will help prevent chronic undercharging and discharging too deeply.

    Batteries don't die, their owners kill them.


    " My truck has 8 batteries: a starter, a bank of six in an outside box, and one on the generator. Would I need 3 monitors to keep an eye on, as they're in 3 different locations?"

    Yes, probably, but it depends. It depends on how they are charged and discharged, and if they are interconnected together (a redundant term, I know).

    Chances are, a real battery monitor for the house bank, and then maybe a Battery Minder for the starter battery, and possibly a Battery Minder for the generator battery (if you should even care to monitor that one).

    If the starter battery is totally isolated and is used solely for starting and truck loads (lights, radio, etc.) and the truck's alternator handles its recharging, then that battery would need its own monitor. And if that battery is used as such, and has little or no "key-off" amp loads on it (like an inverter), then monitoring is probably not even necessary, and at most, one of the UPG Battery Minder low voltage alarms is sufficient to alert you when the battery has finally seen it's best days.

    The generator's starting battery would also need its own monitor, but again, probably just something like a Battery Minder would be fine.

    The 6-battery house bank would greatly benefit from a battery monitor like the Xantrex.

    If all of the batteries (or any combination of them) are combined via a solenoid or isolator or something like that, to allow for all of them to be charged at the same time, say, via the generator, or the truck's alternator, or shore power, but are then separated from each other when the charging source is removed, then you would definitely want to use a separate monitor for each.

    But again, monitoring the starter and generator battery, two batteries that will not likely be subjected to deep cycle applications, a Battery Minder will do for those.

    A word about battery monitors. I keep on suggesting the Xantrex Battery Monitor. I don't want anyone to get the idea that I'm pushing Xantrex, 'cause I'm not. There are other others there that will do essentially the same job, some cost more, some cost less. But, for our purposes, the XBM is the most bang for the buck. It's the most accurate, with the latest technology, has the most features, and is the most customizable of the bunch when you factor in the cost versus what you get. You can go cheaper and likely regret it, and you can go much more expensive and get a lot of additional features that are utterly useless in our type of application. There are some (Trimetric) that are slightly less expensive and have slightly fewer bells and whistles, and are essentially as accurate (but have really sucky displays :) ).

    The key features that the XBM has that most others do not are:

    Battery temperature sensing for more accurate monitoring of true energy (kW hours) in and out of the battery.

    Peukert Effect compensation to allow for different available amps based on different rates of charge and discharge.

    Has "alarm contact terminals" that can be used to work much the same as a low voltage alarm (can be used for either low voltage alarm, or low amp state-of-charge alarm) and will control the circuit flow to awaken, say, an automatic generator starter or an external battery charger.

    Has a serial data port that can be connected (via the optional computer communications kit) to connect the monitor to your laptop to do more advanced real-time and historical monitoring of the batteries.

    A "real" battery monitor is likely overkill for starting batteries, unless you use those same batteries for deep cycle operations. If you do use the same bank for starting and deep cycle operations, or have a separate battery bank for deep cycle operations, then a battery monitor is a must.

    But even at that, the monitor is only s small piece of the puzzle. All batteries are not created equal. You can't use deep cycle batteries and expect them to charge with a charging system that is designed for starting batteries. This means a regulated charging system that is designed for charging up a house bank (AGM, gel, other deep cycle batteries). That can be accomplished by a battery charger tied to shore or generator power. Or, through the use of an external, programmable regulator on the truck's alternator to charge the house bank directly, and then using something like a Duo Charge (Balmar) or Echo Charge (Xantex) to keep the starter batteries properly charged.

    Slow and steady, even in expediting, wins the race - Aesop
  16. unorthodoxneon

    unorthodoxneon New Recruit

    Hey turtle, When i move into my house and set up my Windmill and PV system on a battery back up. How much would i have to pay you to hook up the batteries? :+

    Great reading here. Really good to know. I do have one question though. What is the Optima Red Top batteries considered, and for that matter what about the other colored tops? I have one in my personal vehicle that has been drained once due to a light being left on and its going on about 5 years or so now. Just recently after a nice long trip. I took the battery out and had it tested and the volts were 12.6 which is about where a battery should be at.
  17. Turtle

    Turtle Administrator Staff Member

    Actually, be very careful calling it a windmill around most alternative energy geeks. They will quickly correct you by explaining that no wind is milled and that it is a wind turbine, not a wind mill. Picky little snots, aren't they?

    Optima batteries are AGM's constructed with lead grid (sponge) plates in a spiral configuration versus the traditional vertical hanging configuration. The advantages of Optima spiral technology over traditional wet cell batteries is precisely the same as that of any AGM, but the Optima Spiral technology is better marketed. :) The perceptual hye is that somehow Optima Spiral AGM technology is different than regular AGM technology, but it's all hype. The technology is exactly the same. The spiral configuration is a spool if thin lead plate grids whereas other AGM's consist of the same exact lead grids that is pressed together rather than wrapped in a spool. End result is the same.

    Optima batteries are marketed so that somehow the Optima deep cycle batteries are magical and different. They're not. Optima has two kinds of batteries, the Red Top SIL (Starter, Ignition, Lighting), which is a starter battery, and the deep cycle Yellow Top (car) and Blue Top (marine and truck) batteries, which are dual-purpose, hybrid "marine" batteries. The Yellow Top and Blue Top batteries are identical to each other except for the color of the top, and in some cases the terminals are different on the Blue Tops because they are most often marketed as marine batteries, so they have the appropriate terminals that you usually find for those applications. The Group 31 Yellow Top and the Blue Top are identical, but what self-respecting boat owner would put a Yellow Top car battery in his boat? Puhleeze.

    The Yellow Top and Blue Top are marketed as deep cycle, but they are not true deep cycle batteries. They are dual purpose, same as any "marine" battery at Wal Mart or the marina. They have the starting power to start engines, and have the thicker plates necessary for higher and somewhat longer sustained amp draws. They work best for trolling motors, car audio, backup and emergency lighting (because like all AGM's, they have a very slow rate of no-load, self-discharge), winches.

    Compare the largest battery optima makes, the D31A (auto-truck, Yellow) and D31M (marine, Blue) and it's 75 amp hours, 155 minutes of reserve time, to a Concord Lifeline marine (and RV) cranking battery, the GLP-3100T, and you'll notice that in the same Group 31 size, the Concord has 228 minutes of reserve time, the same cranking amps, and is a 105 amp hour battery. The Lifeline battery weighs 8 more pounds (more lead, more amp hours) and costs $100 more than the Optima, though.

    But, the same group 31 in a true deep cycle battery, like the Concord GPL-31T, it only has 105 amp hours and 195 reserve minutes, and less cranking amps than either of the above, but it's a true deep cycle battery with solid lead plates and will therefor handle more and deeper discharge cycles, and can handle higher amp draws (microwave) without shortening its lifespan.

    They key really is to match the battery to the application, and to keep it properly charged. You wouldn't want to use a GLP-31T as a starter or trolling battery, anymore than you'd want to use an Optima D31 in a house bank. Either battery type will perform equally as well when used in the right application, and either battery will perform equally badly when used in the wrong application. By the same token, you can't put AGM true deep cycle batteries into a charging system that is designed for traditional wet or hybrid AGM batteries and expect the true deep cycle batteries to perform well. They have different charging requirements.

    The Red Top in your personal vehicle sounds like it's in great shape, which would make sense if it's used as a starting battery and the alternator keeps it well charged up and cared for. It should last anywhere from 5-8 years, maybe more. That's the benefit of proper charging moreso than of it being an Optima battery. Any AGM that's designed for starting (or dual purpose) will far outlast traditional wet and maintenance-free batteries in such an application.

    Another benefit of an AGM as your starting battery is that AGM's have more cranking amps at extreme cold temperatures, plus, they can be drained dead by leaving a light on once in a while without drastically shortening their lifespan. You leave a dome light on overnight with a regular battery, just once, and drain it down, and you've probably just cut in half the total lifespan of that battery. You can do that once or twice a year with an AGM and it'll keep on keeping on.

    Slow and steady, even in expediting, wins the race - Aesop
  18. unorthodoxneon

    unorthodoxneon New Recruit

    Thanks for the reply. And yes i should of said Wind Turbine but Wind Mill is what rolled off my fingers. I like my Optima cause even in the cold weather it has little to no starting issues that a "regular" battery would have. One reason i asked that question is a picked up one of those digital battery chargers and AGM/GEL is one of the selections for charging a battery and i just wanted to make sure if i had to charge the battery i didnt charge it wrong.
  19. Turtle

    Turtle Administrator Staff Member

    If it weren't for the Sprinter's charging system being dictated by a Bosch alternator that refuses to put out the required voltage for an AGM, I'd probably have an AGM starter battery on this thing. AGM batteries are the batteries of choice in places like McMurdo Station, South Pole.

    Do take a good look at that charger and try to find out exactly what it is doing when set for AGM/Gel, because AGM and gel batteries have different charging voltage requirements. Put a voltmeter and an amp meter on it to see what's going on. Multi-purpose batter chargers can often be a problem.

    The voltage a battery needs, all batteries, will change depending on the temperature of the battery, but gel batteries are very sensitive to voltage and should generally be charged by a charger made expressly for gel batteries.

    AGM's require a constant voltage of 14.2-14.4 volts, and then when fully charged can be removed from the charger, or they can be left on and subjected to a float charge of 13.2-13.3 volts. That's at 70 degrees. If the temp goes up or down 10 or 20 degrees, that's not that big a deal with AGM batteries, since they prefer a constant voltage and variable amperage.

    With gels, they prefer constant voltage and variable amps, but they are far more picky about the voltage with regard to the temp. At 70 degrees, a gel battery should be charged at 13.7-14.0 volts. That's a lower voltage than an AGM at the same temp. And if you try and charge a gel at 14.4 volts when it wants a max of 14.0 volts, you'll fry the gel.

    The question becomes, when you flip that switch on the charger to AGM/Gel, what's the charger really doing? Because, the same setting simply will not work for both AGM and gel. The requirements are not interchangeable. If it's charging at 14.2-14.4 you're good to go. Just don't put a gel battery on there. But, if it's charging a little low in order to accommodate a gel, with the manufacturer figuring that the lower voltage is fine for AGM's, they'll just take a little longer to charge, then your AGM is well on its way to an early death.

    AGM batteries are a relatively recent advent, and old habits die hard. Many people, far too many manufacturers of battery chargers included, believe that you can charge a battery, any battery, AGM's included, at a lower voltage and it will eventually be fully charged, but it might take it a little longer to charge. And they're wrong. I know it makes sense, and it seems logical, that's the way it's always been, but they're still wrong.

    They're correct when it comes to wet cells, as wet cells (the batteries we are all the most familiar with) are designed to charge with a constant amperage and a lower, usually variable, voltage. That's why most of the chargers you see are 10, 20, 30 amp chargers, and they will output a constant number of amps, but will do so at a lower voltage to keep the batteries from boiling.

    But an AGM is designed for constant voltage and variable amps. Just the opposite from traditional batteries.

    Most multi-purpose battery chargers are simply regular constant amp chargers that will pump up the voltage slightly when switched over to the "deep cycle" or AGM/Gel setting.

    Most people, end users, charger manufacturers, they don't see an immediate OGM! in-your-face problem when charging AGM's on a multi-purpose charger. In fact after a while, the charger will light up a little light and tell you that the battery is fully charged. It's lying, tho.

    When you charge an AGM at too low of a voltage, I don't care how long you leave it on the charger, it will never, ever, get fully charged. It can't. As amps are pumped into a battery, the internal resistance rises. And when resistance rises, voltage drops, and when voltage drops with a constant amp charger, volts X amps equals watts, therefor less volts times constant amps equals less watt energy being pumped into the battery.

    What happens with an AGM is, as the battery starts to charge, it will eventually reach the same internal resistance as the charger's voltage output, and it will do this at about 80% capacity. Doesn't matter how long you leave the charger on, when the charging voltage and the battery's internal resistance match so that there's no amp flow in or out, it's a standoff, and the charger will not pump any more amps into the battery. It can't.

    When the battery will not accept any more amps, and when the charger cannot pump any more amps into the battery, the standoff, the charger thinks the battery is fully charged, and will tell you the same. But it's only about 80% charged.

    When a Reserve Capacity test is performed on such a battery, something that most people are not gonna do, much less know how to do, it will confirm the battery is not fully charged. When a battery is routinely undercharged like this, its actual capacity will then become about 80% of it's rated capacity. Your 100 amp hour battery becomes an 80 amp hour battery (sulfation). At that point, 80% of 80 amps is 64 amps capacity, and the sulfation begins the vicious cycle of an early death.

    The reason this isn't an OGM! in-your-face problem that no one ever complains about is that it's a gradual process, one that doesn't present itself immediately upon disconnecting the charger from the battery. The battery works, no problem. "Hey, I do this all the time, battery still works! No problem!" Ignorance is bliss. In the meantime, a battery that could have, should have, lasted 7-10 years dies a quiet death in year 4 or 5.

    So do check out what that charger is doing. If it's putting out the proper voltage, great. If it's not, it still might not be a big deal, as you aren't discharging the battery too deeply very often, and the vehicle charger is likely keeping it properly fully charged on a routine basis. If the charger is falling a little short, and it becomes your primary charging method, then it becomes a big deal.

    Slow and steady, even in expediting, wins the race - Aesop
  20. danthewolf00

    danthewolf00 Active Expediter

    ok i just bought 2 1100 something cca starting batterys for a house bank for my espar and qc and plan to add a 1000 watt cobra inverter...what i need to know is whats the rate of hours you get per cca or at least whats the fourmla for it. please and thank you

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