Charging my Aux batteries. What am I doing wrong?

[chetjester]

I've read everything I can find but appear to have something wrong. I have a 2010 Sprinter. I'm using 4 gauge wire throughout my circuit.

From the positive terminal of the van battery I am wired to a 150 amp breaker. From there, I am wired to a fairly expensive battery isolator. All this is under the driver seat.

From the isolator, I run a cable to the passenger seat to the positive terminal of my first battery. I have a cable from the positive to the positive of the second battery. I have a cable from the negative first battery to the negative second battery and a cable from the negative second battery to a grounding bolt on the floor under the passenger seat.

Why does it take so long to charge my batteries? Should I be running this circuit from the alternator? If so, where would that connection be? Is it in the circuits under the driver seat? Do I need a small charger running off a small inverter to augment the slow charge I'm getting from the main battery?

Apparently I have done something wrong. I've been sitting in Laredo for 4 days and have lost all my charge on my aux bank and just running the van for a while does not charge them back up. Maybe that's the way it's designed to work. Maybe if I were busy and driving the van more I wouldn't have this problem.

Any suggestions?

Thanks.

 

[greg334]

Regardless what anyone else says, start with a digital volt meter.

If you don't have one, go to harbor freight and buy their $7 volt meter - no buy two of them and keep one at home.

AND learn how to use it.

Once you have accomplished that, then check the voltages at the battery to see what they are and work your way through your setup.

AN alternative is to go to eBay, search for Panel Meter and use that to monitor the voltage.

 

[purgoose10]

I've read everything I can find but appear to have something wrong. I have a 2010 Sprinter. I'm using 4 gauge wire throughout my circuit.

From the positive terminal of the van battery I am wired to a 150 amp breaker. From there, I am wired to a fairly expensive battery isolator. All this is under the driver seat.

From the isolator, I run a cable to the passenger seat to the positive terminal of my first battery. I have a cable from the positive to the positive of the second battery. I have a cable from the negative first battery to the negative second battery and a cable from the negative second battery to a grounding bolt on the floor under the passenger seat.

Why does it take so long to charge my batteries? Should I be running this circuit from the alternator? If so, where would that connection be? Is it in the circuits under the driver seat? Do I need a small charger running off a small inverter to augment the slow charge I'm getting from the main battery?

Apparently I have done something wrong. I've been sitting in Laredo for 4 days and have lost all my charge on my aux bank and just running the van for a while does not charge them back up. Maybe that's the way it's designed to work. Maybe if I were busy and driving the van more I wouldn't have this problem.

Any suggestions?

Thanks.

Turtle has a post with pictures of his install, look for that. One main thing I see wrong is the 4 ga wire. Your current is restricted and won't flow freely. You should have 1ga minimum, but better 1 o/t. Remember the path of least resistance. Check your volt meter and see what your amp draw is, if its over 15 amps you need bigger cable. 4ga is not enough. The larger the cable the faster the charge.

 

[Moot]

I've been sitting in Laredo for 4 days and have lost all my charge on my aux bank and just running the van for a while does not charge them back up.

Just running the van for awhile will not do much as far as recharging. If you have two aux. batteries it could take 8 hours or more at idle to charge them. What is the amp hour rating of these batteries? What devices are being powered?

Turtle's Sprinter requires a battery separator rather than an isolator. Apparently there is a difference and I'm sure he will explain and diagnosis your problem in typical techno Turtle fashion.

Oh yeah, what Greg said, get a hand held digital volt meter.

 

[chetjester]

Thanks for the 2 replies so far.

I have a multi-meter. It is sitting at home and I'm in Laredo.

I saw Turtle's setup and also saw that he said 4 gauge wire would be ok. In addition, Espar of Michigan, where I bought my Espar and the Isolator and breaker recommended 4 gauge.

What I'm trying to understand is if I should expect those aux batteries to charge as quickly as the main battery. If my problem is that I have been sitting for 4 days with only occasional idling, then maybe I just have to get back on the road to get them charged back up.

I have a Pulsetech XTreme Charger at home that I can run off my 300 watt inverter plugged into my cigarette lighter which could provide charging while I'm idling but not driving.

I saw that Turtle isn't using an isolator. He has a charger running from the main battery to his battery bank. Could my isolator be pinching the flow? Guess I won't know until I check the voltage.

 

[chetjester]

I have 2 deep cycle marine batteries. Lead/acid. One is 85 amp hours and the other is 105 amp hours.

I'm only running my Espar, at this time. But, I ran it during the day Friday, Friday night, during the day Saturday, Saturday night, some time during Sunday and Sunday night and just a short while yesterday. When I went to start it last night (64 degrees and I need a heater? What a whoose I am!), it didn't have enough power to start and my inverter, which I usually have turned off, screamed at me when I turned it on.

I have been having trouble understanding why the aux batteries don't recharge as fast as the truck battery. Is the the truck battery so much closer to the alternator that it gets a faster charge?

I would have had this installed professionally by Espar of Michigan, but I can't seem to get to Michigan.

 

[Moot]

Hang tight Chet, I'm sure Turtle will respond today. Espar running in Laredo? What do you do if you go north of Austin?

I see you have 2 different size batteries. Is one or both old?

 

[purgoose10]

I have 2 deep cycle marine batteries. Lead/acid. One is 85 amp hours and the other is 105 amp hours.

I'm only running my Espar, at this time. But, I ran it during the day Friday, Friday night, during the day Saturday, Saturday night, some time during Sunday and Sunday night and just a short while yesterday. When I went to start it last night (64 degrees and I need a heater? What a whoose I am!), it didn't have enough power to start and my inverter, which I usually have turned off, screamed at me when I turned it on.

I have been having trouble understanding why the aux batteries don't recharge as fast as the truck battery. Is the the truck battery so much closer to the alternator that it gets a faster charge?

I would have had this installed professionally by Espar of Michigan, but I can't seem to get to Michigan.

When I said 4 ga wasn't enough I may have mis-spoken. 4ga is enough but when you get further away from the charging source with a normal alternator like a 100amp or so you need to be able to send the charge easier with less restriction. When your battery's are pulled down as you suggested it takes a good deal of running to recharge. I would not run the battery's more than 8 hours w/o running the engine for a couple of hours to recharge.

 

[chetjester]

You're funny, Moot. I lived in New England for 44 years, but now live in Arlington, TX. I hate the cold so much. I just run the heater on very low so I don't have to wear much to bed.
.
I bought the first battery from AutoZone this summer and carried it for about 2 weeks thinking it could run a fan and some other stuff in my van. I didn't hook it up to the main battery. I tried charging it with my Pulsetech. I took it out the next time I went home. I bought the second battery 2 weeks ago from Walmart on the advice of Turtle's posting.

Both batteries were at 75% when I installed them. My inverter showed 12.3 volts.

Since I installed them, I first sat for a week still on vacation. I ran the heater 2 nights in Arlington when the temperature went below 28 degrees so nothing would freeze in the van. I got a load on Tuesday, Jan 11 to Tucson. I arrived Wednesday morning. I ran the heater Wednesday night. I got a load from Nogales to Laredo Thursday which I delivered Friday.

I think maybe I just haven't been running enough to charge and keep charged the batteries.

 

[Moot]

You're funny, Moot.

I'm also brain dead. I have lived in Minnesota all my life.

In theory the isolator won't start charging the house bank until the starting battery(ies) are charged. So the starting batteries get charged first and then the house bank. Charging 3 or 4 batteries at idle is going to take some time. A whole lotta time. Does your Sprinter have 2 starting batteries?

 

[chetjester]

Living in Arlington, TX was the luckiest thing that ever happened to me when I started expediting in 2004. Do you realize how often I can drive home en route to any place north from Laredo/McAllen/El Paso and south to Texas? I never take home time because I always pass by the house. I'm just south of I-20 near 360. Halfway between I-35E and I-35W.

My sprinter only has the one battery under the floor on the driver side. It's quite a large battery. But, it can't run my Espar and Truckfridge cooler all night.

I think I'm just going to have to find a way to supplement the charging to be sure they charge as fast as they can when I have to sit too many days. If freight would pick up better I would be driving and not having this problem, right?

The idling is a slower charge than the draw from the Espar. It stands to reason that I have run the batteries down.

 

[highway star]

Nogales to Laredo should have had everything charged if it's wired properly. Bad isolater?

 

[chetjester]

A bad isolator was my next guess. But until I can get a volt-meter I have no way of knowing if I have a circuit from the main to aux battery through the isolator.

What would happen if I bypass the isolator temporarily so long as I can monitor the starting battery to be sure it stays charged? If I see the starting battery losing too much power (I have an indicator light on my 3 station 12 volt outlet), I can easily trip the breaker to break the circuit between the batteries.

Does the isolator reduce the amount of charge going to the aux batteries? If I didn't have the isolator in the circuit, would I charge faster?

 

[Moot]

Truckfridge cooler, there's an amp draw that wasn't mentioned earlier.

 

[chetjester]

Yes, the Truckfridge would be an issue, except I no longer have it running off the inverter from the aux batteries. It's running off the main battery. The Truckfridge uses less draw than a Coleman cooler that runs all the time.

When I was driving from Nogles to Laredo, it was mostly night driving. I had everything running. Lights, radio, fridge and inverter. I stopped several times for fuel and checked my inverter and noticed it wasn't showing any more voltage. I turned off the inverter and moved the fridge to a 12 volt socket under the driver seat and continued on my way. It only went from 11.7 volts to 12.0 volts in over 400 miles.

That's why I think something is wrong with my setup. It seems to point to the isolator. I'm not really sure I have power to the aux batteries and need that volt meter. I'm going to head over to WalMart on Loop 20 and see if the have a cheap one I can buy to test the circuit. Then, I might call Espar to see if they might know what I might have done wrong with their isolator. Could it be wired backward?

 

[Moot]

I run my Garmin, phone charger, c.b., compass, clock, alarm clock, aux. interior lighting, 12 volt cooler, small inverter for laptop, flashlight charger, Fantastic Vent and other stuff from 2 deep cycle marine batteries. I have a deep cycle charger with a desulfate mode at home. Per Turtle's recommendation I put that charger on the house bank when I am at home.

 

[greg334]

I don't know what Turtle is going to tell you, but I can tell you that troubleshooting the layout is not possible via a forum.

You have to look at what voltage the batteries are getting at the posts and work backwards.

 

[chetjester]

I just bought a multi-meter at Walmart and I'm set to start checking the circuit. Wish me luck.

 

[Moot]

First thing I would check is the voltage of the starting battery with the engine off. Then check voltage of the house bank. Start the motor and see what voltage the alternator is sending to the starting battery and to the house batteries.

 

[chetjester]

Yeah....

Just because I bought a multi-meter does not make me smart enough to know how to use it. I was able to get a lot of sparks, but no readings. I know I have a circuit up to the isolator. When I check if there is voltage coming from the isolator to the aux batteries, I don't know if I am reading a residual charge on the aux batteries or power through the isolator. I don't seem to know how to use the darn thing.

I'm going to try Best Buy at noon (central) when their auto audio installers arrive. They should know how to read a meter.