Battery Powered A/C
- Thread starter Broompilot
- Start date
tractorman70
Seasoned Expediter
Turtle,
I was looking over the Camping World site, and saw they have many a selection of roof mounted A/C units that run on 115 AC.
My question is, could one of those work with the right battery pack and inverter set up? Some even have a heat strip that can be added as well.
Thanks in advance!
I was looking over the Camping World site, and saw they have many a selection of roof mounted A/C units that run on 115 AC.
My question is, could one of those work with the right battery pack and inverter set up? Some even have a heat strip that can be added as well.
Thanks in advance!
tractorman70
Seasoned Expediter
I'm not an electrician by any means but it appears to me that unit is meant for use while the truck is in operation and the batteries are being recharged "if you will". My limited knowledge of such things tells me running this one off of batteries solely is gonna take a lot of batteries.
First and foremost, whether you're an expediter or an RVer, the heat strip on a rooftop air conditioner will not, not, not keep you warm. It'll take the chill out of a brisk 50 degree morning in the campground, but that's about it. The heat strip of a rooftop air conditioner has shattered the hopes and dreams of countless RVers.
Second, resistive heat applications, as with an electric heater, air conditioner, dish washer, etc., do not get along with and play well with battery power. People who live off-the-grid using solar and wind power stored in batteries will still be on the grid for the big electrical appliances, or they'll have some high dollar alternatives, like nine thousand dollar DC refrigerators.
Converting from 115 (110-120) volts AC to 12 volts DC is a 10-times proposition. If a rooftop air conditioner draws 10 amps at 115 volts, it's 100 amps at 12 volts. Then there's the Peukert Effect where, like MPG, the faster you draw amps from a battery the worse your amp mileage gets, and an AC rooftop air conditioner (or electric space heater) translates to seriously high amp draws from a battery bank.
So, lets say you have a really efficient rooftop air conditioner that only draws 10 amps, which is 100 amps from the battery (a little more than that, actually). If you run it for 8 hours, that's 800 amp hours, except the high draw and the Peukert Effect makes it more like 950 amp hours removed from the battery bank. You don't want to ever go down below 50% of depth of discharge, so you'll need a 1900 amp hour battery bank. And that's if you don't use the battery bank and inverter for anything else, and only if you run the AC for 8 hours a day.
Having fun yet?
A 1900 amp hour battery bank will weigh in at around 1000 to 1100 pounds, give or take. So there's that. Also, with high dollar 2/0 cabling, heavy duty fuses and $8 a pop cable lugs, a 1900 amp hour battery bank will cost you between $2500 and $3000. And that's if you use traditional wet cell batteries. If you go with AGM batteries, double that, at least. Yay.
Also, lets say you have a 30 amp battery charger. Any idea how long it'll take to put 800 amp hours into a bank? It's not 800 divided by 30. It's about 2 days.
Seriously.
If you want to run a rooftop AC air conditioner, the only way to do that is either parked in an RV park plugged into shore power, or with a generator. It's cheaper to use a generator, and your vehicle's suspension will thank you.
In another lifetime,,I did HVAC WORK, REPARIS AND SUCH. IMHO, run ur ac units at 110v supply only,, I=E/R and P=ExI, 2 formulas that will serve u well. I run a 5ooo btu window unit in the summer and will be running a 8k or 10 k this summer,,,and use a gas portable generator,,,always lot of output and it runs 10 hours on 4 gallons of gas, works for me,,there is no substitute for good continuous power and (( no brown outs due to low voltage/amps)) I dont like battery powered stuff on heavy duty appliances,,,its not efficient enough, IMO
tractorman70
Seasoned Expediter
.
Having fun yet?
Seriously.
If you want to run a rooftop AC air conditioner, the only way to do that is either parked in an RV park plugged into shore power, or with a generator. It's cheaper to use a generator, and your vehicle's suspension will thank you.
WOW!! Um that is a very good reason to not go that route, truly an electrician I am not. Thank you for the very informative explanation.
The Red Dot R-6100 was mentioned at the start of this thread.
It is the normal old truck Roof Unit(a Very Good one I might add)that requires an engine driven compressor.
Red Dot does currently have a battery powered unit but it is somewhere around 7000 BTU & is available in 12 or 24VDC.
It is NOT the same one that they had several years ago.
Red Dot(Distributors) also sells the SLEEPINGWELL APU.
All of these are on their web site I believe.
Gordon
It is the normal old truck Roof Unit(a Very Good one I might add)that requires an engine driven compressor.
Red Dot does currently have a battery powered unit but it is somewhere around 7000 BTU & is available in 12 or 24VDC.
It is NOT the same one that they had several years ago.
Red Dot(Distributors) also sells the SLEEPINGWELL APU.
All of these are on their web site I believe.
Gordon
Turtle, what about an insulated Sprinter? Do we get to the same point. Better get a generator to power the AC roof top unit and not a battery bank?
I just insulated my Sprinter last week and now I am looking for a roof top AC unit or even a portable unit as I am kind of tight on my budget right now and possibly a Honda 2000i generator. I really need some help on what type of AC roof top unit I should get. I really no nothing about them and the cooling capacity and all of that. I heard the Honda 2000i generators are the best thought.
Thanks.
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You can run an A/C from batteries, but you need several of them and the A/C needs to be a 12-volt air conditioner. 12-volt air conditioners are really, really expensive, tho. To run a 110-volt A/C with a generator like a Honda, all you need (especially if you are well insulated) is a Coleman Mach III PS (Power Saver), 13,500 BTU, or the Coleman Polar Cub at 9,200 BTU. Both run off the Honda 2000i, and both cost less than $1000.
See this recent thread ( http://www.expeditersonline.com/forum/truck-talk/47727-portable-generator-2.html#post444133 ) on generators for information on adding a hard-start capacitor to the A/C to ease the stress on the generator, too.
See this recent thread ( http://www.expeditersonline.com/forum/truck-talk/47727-portable-generator-2.html#post444133 ) on generators for information on adding a hard-start capacitor to the A/C to ease the stress on the generator, too.
Turtle, can you please recommend a place where they install them? Let's say I have the Honda 2000i and looking to buy the Coleman Polar Cub. Should I buy the roof top unit and find and installer or just look for a seller that installs them and buy it from them. I mean I need somebody that knows how, where and what to install. I would like something like user "asjssl" has, besides he has a window a/c unit but I would like to buy the top roof unit: then the honda 2000i on the back door on the outside of the van and then the roof top unit properly installed on the top of my sprinter.
Any info on where I can get this job done would be greatly appreciated. Thanks
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Well, most any RV place that sells the rooftop units can install it. They're probably gonna be really backed up this time of year working on RVs they actually sold, so that could be a problem. But Camping World will install it. Many independent auto mechanic shops can do stuff like that, especially those you see RV's or boats parked there every now and then to be worked on. If they do that kind of stuff, they can do anything.
These things actually work in a small enough space. Maybe not Laredo in august but they are pretty cool for a cheap solution.
Portable air conditioning - 12 volt - air conditioners - Evaporative coolers
Portable air conditioning - 12 volt - air conditioners - Evaporative coolers
Attachments
RLENT
Veteran Expediter
I'd be looking at a rooftop RV A/C unit powered by a genset - either a portable like a Honda 2000, or one permanently mounted aft of your rear axle underneath the vehicle.
The Honda setup is probably the most economical, in terms of initial outlay.
Wolfie62
Seasoned Expediter
After reading all the responses to this thread, I really have to wonder. Does anyone really believe you can get something for nothing?
Turtle, your answers are spot-on. I appreciate your technical accuracy. Prior to this career, I was a mechanical engineer, specializing in plant/facility engineering. Heat removal requires alot of power. The only time it does not is when one can use an evaporative cooler in a dry climate. For our purposes, that means water (which is HEAVY) and lots of it. Not the best cure for expediters who want to rid the space of heat--weight is expensive also. Not practical unless one can stay in the desert southwest and earn a living there in this business.
Batteries are HEAVY and EXPENSIVE; they are by nature a backup for storing energy, but only limited amounts of it. Batteries also wear out; their performance degrades over time. They also require more energy to charge them than they are capable of storing; they are energy consumers in and of themselves. Battery operated appliances are tremendous energy consumers when one does the math. Therefor, battery operated appliances are cost effective ONLY when the battery draw is small. Think cameras, clocks, watches, and the like. Appliances that draw over 250 watts are not practical for battery power for extended periods and continuous use. (Not even the starter motor of your van or truck is continuous use! And that is the primary use for our batteries as they exist now!)
So then, what is a real-world solution to heat removal for trucks/vans? The only real, practical solution, and one that is kind to the bottom line, is the gen-set/110 volt ac option. By weight, gasoline and diesel fuel store TREMENDOUS amounts of energy in a small space. Using a dedicated engine, powered by gas or diesel, to convert that liquid into usable electricity is about the most cost-effective option for generating the power that is going to be required to remove heat (air conditioning). You don't get something for nothing in the world of energy. (The single best option for avoiding the genset is to use a hydrogen cell for power generation. NASA uses them; they are VERY EXPENSIVE. They combine oxygen and hydrogen into water and produce electricity in the process. For that much money one could buy several "Cadillac" gensets and ALL the fuel one would ever need, plus pay for installation.)
Also, 12 v dc units use HEAVY current draws, use heavy copper wiring, and are subject to corrosion on terminals by the fact that terminals are polarized. Think battery terminal corrosion throughout the truck/van. DC Appliances are specialized and expensive. Alternating current appliances, such as 110/115/120, use smaller wiring (less current draw) and are immune from polarizing terminal corrosion. Components are widely available for appliances, and are reliable.
Invest in a good genset. Get good appliances. Be comfortable. Be kind to your bottom line. Get what you pay for. Be careful of all those new things out there that promise "something" for near nothing. (Their something is your wallet--your nothing is your money wasted.)
Turtle, your answers are spot-on. I appreciate your technical accuracy. Prior to this career, I was a mechanical engineer, specializing in plant/facility engineering. Heat removal requires alot of power. The only time it does not is when one can use an evaporative cooler in a dry climate. For our purposes, that means water (which is HEAVY) and lots of it. Not the best cure for expediters who want to rid the space of heat--weight is expensive also. Not practical unless one can stay in the desert southwest and earn a living there in this business.
Batteries are HEAVY and EXPENSIVE; they are by nature a backup for storing energy, but only limited amounts of it. Batteries also wear out; their performance degrades over time. They also require more energy to charge them than they are capable of storing; they are energy consumers in and of themselves. Battery operated appliances are tremendous energy consumers when one does the math. Therefor, battery operated appliances are cost effective ONLY when the battery draw is small. Think cameras, clocks, watches, and the like. Appliances that draw over 250 watts are not practical for battery power for extended periods and continuous use. (Not even the starter motor of your van or truck is continuous use! And that is the primary use for our batteries as they exist now!)
So then, what is a real-world solution to heat removal for trucks/vans? The only real, practical solution, and one that is kind to the bottom line, is the gen-set/110 volt ac option. By weight, gasoline and diesel fuel store TREMENDOUS amounts of energy in a small space. Using a dedicated engine, powered by gas or diesel, to convert that liquid into usable electricity is about the most cost-effective option for generating the power that is going to be required to remove heat (air conditioning). You don't get something for nothing in the world of energy. (The single best option for avoiding the genset is to use a hydrogen cell for power generation. NASA uses them; they are VERY EXPENSIVE. They combine oxygen and hydrogen into water and produce electricity in the process. For that much money one could buy several "Cadillac" gensets and ALL the fuel one would ever need, plus pay for installation.)
Also, 12 v dc units use HEAVY current draws, use heavy copper wiring, and are subject to corrosion on terminals by the fact that terminals are polarized. Think battery terminal corrosion throughout the truck/van. DC Appliances are specialized and expensive. Alternating current appliances, such as 110/115/120, use smaller wiring (less current draw) and are immune from polarizing terminal corrosion. Components are widely available for appliances, and are reliable.
Invest in a good genset. Get good appliances. Be comfortable. Be kind to your bottom line. Get what you pay for. Be careful of all those new things out there that promise "something" for near nothing. (Their something is your wallet--your nothing is your money wasted.)