Battery-powered AC units for truckers...?

[Borden]

upto date now on the thread and can only say WOW

[EllPea in CA]

Originally Posted by Bob Miller

You guys and ladies may be laughing, but in Bath, U.K. in an 18th century restored home, there is a dog powered wheel that is used to turn a meat spit in a kitchen. Best part. it is located above the fire, if the dog stops running, it becomes dinner for the help....LOL

Geez, I miss Bob Miller.

[Steve Outlaw]

One of the Oliver Owners is running his 13500 BTU AC completely off his batteries. As long as he has full sun, his 360 Watts of solar are putting in more amps than the AC takes out. Even with no sun the 675 amp hours of battery storage will keep him running a long time.

As you know it only takes about 12.5 amps to run the AC after the compressor is started. It's the 60+ locked rotor amps that it takes to start it that is the killer. He has discovered a work around for that and is happily staying cool in the Florida heat.

[Mikmay]

After further testing of the dometic fresh jet 3500 btu air conditioner on the HC1 we have decided that it is the best and well suited to use on the trailer. At 40 lbs it is the lightest and has the smallest footprint on the market. The unit will cool a 13 foot trailer in the calafornia heat to a comfortable temperature but will not turn the trailer into a icebox like the larger units did . Although it is an expensive unit it has a lot of features that other units don't .it has a dehumidifier , heat, led lighting and the ability to run on dc power with the inverter built specifically for the unit. This air conditioner works well with our trailer and I am not endorsing it for a larger trailer as we have not tested it on anything larger .

[Toxdoc]

Originally Posted by Mikmay

After further testing of the dometic fresh jet 3500 btu air conditioner on the HC1 we have decided that it is the best and well suited to use on the trailer. At 40 lbs it is the lightest and has the smallest footprint on the market. The unit will cool a 13 foot trailer in the calafornia heat to a comfortable temperature but will not turn the trailer into a icebox like the larger units did . Although it is an expensive unit it has a lot of features that other units don't .it has a dehumidifier , heat, led lighting and the ability to run on dc power with the inverter built specifically for the unit. This air conditioner works well with our trailer and I am not endorsing it for a larger trailer as we have not tested it on anything larger .

Hi mike,

Have you had any experience running it from solar? Thanks!

[Raz]

Originally Posted by Steve Outlaw

One of the Oliver Owners is running his 13500 BTU AC completely off his batteries. As long as he has full sun, his 360 Watts of solar are putting in more amps than the AC takes out. Even with no sun the 675 amp hours of battery storage will keep him running a long time.

As you know it only takes about 12.5 amps to run the AC after the compressor is started. It's the 60+ locked rotor amps that it takes to start it that is the killer. He has discovered a work around for that and is happily staying cool in the Florida heat.

Something wrong here Steve. An air conditioner drawing 12.5 amps is using power equal to 12.5 x 120 or 1500 Watts. The use is much greater than the 360 Watts provided by the solar. Further, 12.5 amps alternating current would require125 amps DC into a 12 volt to 120 volt inverter. While 675 amp-hrs is quite the battery set up, I don't see how it could meet that demand. There is something your friend is leaving out. Raz

[Mikmay]

Originally Posted by Toxdoc

Hi mike,

Have you had any experience running it from solar? Thanks!

Yes all of our testing is with a 100 watt flex panel.

[Raz]

Originally Posted by Mikmay

Yes all of our testing is with a 100 watt flex panel.

I don't mean to ruin the party but..... Thirty five hundred BTU equates to 1025 Watts. At 12volts that would require 1025/12= 85 amps. You might get 5A. out of a 100 watt panel. Even with golf cart batteries, that's a heavy drain. Like Steve's, the numbers don't seem to add up for battery operation? What am I missing here? Raz

[trumpetguy]

Hey ya'll. I am the Oliver owner running the AC with battery power. And regardless of what all the engineer types say it works. Now you may have an argument, but I have an experience. A key to this may be the Atwood Air Commander 13500, which is advertised to run on a Honda 2000i generator. I can attest to the fact that it will run on that small generator...even with a Propane carb, which I have.

So it occurred to me that if I could get past the LRA issue I could possibly start and run the Atwood using my 2000 W inverter and a transfer switch. I ran the unit on batteries for eight hours yesterday and it was close to 100 degrees. My Blue Sky remote showed 12 Volts and 93 percent full when I shut down.

I do have six Trojan T105 6V batteries with 362.5 usable Amp hours and they are connected with 4/0 welding cable. That does help. Keep those babies fully charged as in Handy Bob's blog and they will treat you right.

Is there magic here...maybe a little black box? Am I going to rely on batteries for AC full time? Heck no, but is sure is nice to have the capability.

If you see me at a rally check it out. Trailer name is Setting Sail and my Oliver is hull #64.

Enjoying my naps and lunch breaks with full AC and no generator I am...

trumpetguy


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[trumpetguy]

One final comment. The compressor draws most of the Wattage and it cycles on and off leaving only the fan running so the draw is not continous. The Oliver's double hull construction provides a level of insulation not found in most other trailers, which makes for a more efficient setup.

The AC is 13500 BTU but Atwood advertises it has the same out as a 16500 BTU unit.


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[Raz]

Originally Posted by trumpetguy

Hey ya'll. I am the Oliver owner running the AC with battery power. And regardless of what all the engineer types say it works. Now you may have an argument, but I have an experience.

Well, I'm the only engineering type that posted and I'm simply quoting physics.

My Blue Sky remote showed 12 Volts and 93 percent full when I shut down.

You ran a 13.5k BTU AC for 8 hrs on 6 Trojan 105's and your batteries were still at 93%. Figure out whats in the black box and patent it . I wish you and handy bob well. Raz

[Mikmay]

Originally Posted by Raz

I don't mean to ruin the party but..... Thirty five hundred BTU equates to 1025 Watts. At 12volts that would require 1025/12= 85 amps. You might get 5A. out of a 100 watt panel. Even with golf cart batteries, that's a heavy drain. Like Steve's, the numbers don't seem to add up for battery operation? What am I missing here? Raz

I'm not sure as I'm not an engineer and I'm very bad at math but I do know the air conditioner with a 100 watt panel and1 Agm battery with the inverter that comes with the the unit will defenetly work on DC for an extended period of time and of course it will vary with the amount of sun and the use of other DC items . The HC1 is of similar build as the Oliver with double hull and insulation between and this also helps as Dave stated. We also don't endorse the use of DC power as the sole power source for the fresh jet 3500 but as a way to supplement its use such as short rest stops or late evening cool down .

[Raz]

Originally Posted by Mikmay

I'm not sure as I'm not an engineer and I'm very bad at math but I do know the air conditioner with a 100 watt panel and1 Agm battery with the inverter that comes with the the unit will defenetly work on DC for an extended period of time and of course it will vary with the amount of sun and the use of other DC items . The HC1 is of similar build as the Oliver with double hull and insulation between and this also helps as Dave stated. We also don't endorse the use of DC power as the sole power source for the fresh jet 3500 but as a way to supplement its use such as short rest stops or late evening cool down .

Mike, I suspect you are really giving that battery a work out. Clearly someone sized the battery to inverter wire for a maximum current so someone must have a clue how much the AC is drawing. Knowing the amp-hrs rating of the battery, it's easy to determine how long the AC can be used without shortening the life of the battery. I'm sure the owners will let you know for sure. Take care, Raz

[Byron Kinnaman]

I might have the answer to how our friend is running his AC with battery. First off it takes the generator running to start the AC, I think that's what I read.
After the AC goes through a cooling cycle it shuts down, the generator shuts down. Generator is demand type, start when there's a demand and shuts down when demand drops below some level.
The battery keeps the AC's control system running (low current) until the next cooling cycle, when the generator starts again the whole cycle repeats.
Conclusion... AC is NOT running battery power, only the AC control system is.

[Byron Kinnaman]

FYI The laws of physics that RAZ has refereed to are well known and have been around for well over 100 years. I've used that law for the last 60 years and never known it not to work.

[Steve Outlaw]

Originally Posted by Byron Kinnaman

I might have the answer to how our friend is running his AC with battery. First off it takes the generator running to start the AC, I think that's what I read.

He is not using a generator to run or start the AC. It is running off his batteries with the solar panels providing the replacement power. I'm getting the impression there are those that just simply don't believe it is being done because they can't make the numbers match. Hell, I couldn't make the numbers match before he started this project and I told him it would not work. But it does. I believe it has something to do with elves or possibly Elvis.

Physics say a bumblebee can't fly, but somehow it does.

[Byron Kinnaman]

Originally Posted by Steve Outlaw

He is not using a generator to run or start the AC. It is running off his batteries with the solar panels providing the replacement power. I'm getting the impression there are those that just simply don't believe it is being done because they can't make the numbers match. Hell, I couldn't make the numbers match before he started this project and I told him it would not work. But it does. I believe it has something to do with elves or possibly Elvis.

Go read his post again. I believe he mentions a generator involved. It's NOT possible to run and AC with that small a battery. If it was I could run my whole trailer with a single AA battery. I've not heard of any body creating a perpetual motion machine. You don't get something for nothing in the world of physics.

[Mikmay]

Originally Posted by Byron Kinnaman

FYI The laws of physics that RAZ has refereed to are well known and have been around for well over 100 years. I've used that law for the last 60 years and never known it not to work.

Yes I am sure those laws apply to us also although we are trying to break as many laws as we can building the HC1 ha !ha ! but as I stated before the real benefit of this unit is its lightweight , half the weight of any other , being able to run it off of the smallest of generators and the ability to run the fan off of DC pretty much perpetually as all bigger units will only run on AC . No more having to install an air conditioner and a max fan . I am also not endorsing this unit for anything over a 13 foot trailer although the website states it is ok on a trailer up to 7 meters which by my bad Math is approx 22 feet.

[Raz]

Originally Posted by Steve Outlaw

I'm getting the impression there are those that just simply don't believe it is being done because they can't make the numbers match.

You are quite correct. That's what engineers do. Otherwise all you get is magic and snake oil. No offense but this is pretty basic stuff. My best guess is that David is also giving his batteries a real workout and that his monitor is giving bad numbers. A simple volt meter could confirm it. Take care, Raz

[trumpetguy]

Hey Raz. You with Blue Sky right? My meter is a Blue Sky so what might be wrong with it. The charge controller had to be returned for a bum resister so maybe that's the problem.




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