The Ford Barn

Gold Digger · 06-28-2025, 09:37 PM

Been hearing about new 12 volt air conditioners on U-tube. Wondering if anyone has put one in a Model A yet? I know Model A's are 6 volts but I might consider a change to 12 if it was worth all the work installing and if they actually put out enough cool air. The older I get the more the heat bothers me and I drive my Tudor almost everyday.

Bruce of MN · 06-29-2025, 04:32 AM

I would compare the compressor motor amp draw to the 12v alternator output. My first reaction would be that a belt driven compressor would draw less horsepower than the intermediate conversion to electrical power.

nkaminar · 06-29-2025, 04:40 AM

A link please.

Bruce has a good point. You would have to consider the efficiency of the alternator and compressor motor. The advantage may be ease of installation.

Bruce of MN · 06-29-2025, 05:01 AM

I had saved this from a previous thread on the topic:

https://www.amazon.com/Conditioner-U...0D3QKCFK2?th=1

I don't find a spec on current draw.

TomInCologne · 06-29-2025, 05:17 AM

Quote:

Originally Posted by Bruce of MN

I had saved this from a previous thread on the topic:

https://www.amazon.com/Conditioner-U...0D3QKCFK2?th=1

I don't find a spec on current draw.

The ad mentions 10.000BTUs, assuming they mean BTU/h. That is about 3kw. Being generous and assuming a cop of 3, this gives 1kw of electrical input. At 12V that‘s 83A…

nkaminar · 06-29-2025, 06:42 AM

Sponsored Links (Register now to hide all advertisements)

The ad does say 3,000 Watts of cooling. If that is what is drawn from the alternator/battery then that would be 250 amps at 12 volts. Tom, above, uses a COP of 1 KW so in that case the average amperage would be 83 amps. This may be a good choice for a boat with a large solar system or Diesel generator and large house batteries but not for a Model A.

Here is the link for the Ken Davis air conditioning system: Several people I have met say that they like his AC system and that they don't notice any draw on the engine power. I don't know if his system is still available. My only complaint for his system is that it takes up a lot of room under the tank.

http://www.kendavismodela.com/AirConditioners.html

Badpuppy · 06-29-2025, 07:24 AM

10,000 BTU would cool a bus. 1K/300W should be enough for an A, but that's still 25A @ 12V, not including efficiency rate.

BRENT in 10-uh-C · 06-29-2025, 07:51 AM

I have a Fordor out of Texas that we are doing and the customer has asked us to install A/C. I believe the technology is not too far off in the future for belt-driven compressors to be obsolete however with the new invertor compressors, I'm not sure the reliability is there yet. It's coming though. Look at 120v mini-split A/C units and how electrical efficient they are.

We recently built a new truck to pull our trailer with, and we installed a 12v powered roof mounted A/C on top of it. The complete compressor is about half the size of a Model-A Generator -and that is the entire compressor & motor unit. Ours is about 9000btu and pulls about 40 amps on turbo mode (maximum) but then settles in about 25 amps on maintaining the temps. The best part is it is tiny. You can barely see it on top of the roof.

nkaminar · 06-29-2025, 08:56 AM

For those who do not know, new electric motors that run off of batteries are permanent magnet AC motors that are driven by a motor controller. The controller puts out variable frequency, multiple phase AC (alternating current), that powers the motor. These are used in all sorts of applications, including model airplanes, for which I am the most familiar. The motors use the rare earth magnets that are super magnetic.

For model airplanes the motors are 3 phase. The controllers and motors are super efficient. These motors, and lithium batteries, have almost replaced the glow fuel engines of our youth. Even for large planes like 1/4 scale. The controller frequency, and thus the motor rpm, is controlled by the radio control, so that the motor can be run from zero to maximum rpm with the throttle stick on the transmitter.

I believe that the inverter compressors that Brent talked about above has one of these super efficient AC motors. Although it could be another type of motor that oscillates, but is still super efficient.

updraught · 06-29-2025, 08:59 AM

Quote:

Originally Posted by BRENT in 10-uh-C

I have a Fordor out of Texas that we are doing and the customer has asked us to install A/C. I believe the technology is not too far off in the future for belt-driven compressors to be obsolete however with the new invertor compressors, I'm not sure the reliability is there yet. It's coming though. Look at 120v mini-split A/C units and how electrical efficient they are.

We recently built a new truck to pull our trailer with, and we installed a 12v powered roof mounted A/C on top of it. The complete compressor is about half the size of a Model-A Generator -and that is the entire compressor & motor unit. Ours is about 9000btu and pulls about 40 amps on turbo mode (maximum) but then settles in about 25 amps on maintaining the temps. The best part is it is tiny. You can barely see it on top of the roof.

Just for info: The inverter means it can ramp up and down instead of being fixed out put.
It means you can have a bigger unit and it will vary the out put, rather than going on and off all the time if it is sized too big for the area.
This became standard 20 something years ago in home units, here in Oz at least.

nkaminar · 06-29-2025, 12:46 PM

Like my model airplane electric motor.

Gene F · 06-29-2025, 01:40 PM

There is a Model-A chapter in TN some place that a fair number of the members have tinted their windows a little, and installed A/C in them. They mount the condensor under the coach. I know my wife was talking to one of their wives at the national meet once. She said it's not like a modern car, but it's not bad. It does require the high-compression head, at a minimum. Car needs to go 12V with an alternator too.

ModelAArmy · 06-29-2025, 05:31 PM

I have AC in my car. Ken Davis in Texas sells a kit to install A C in a model A.

ModelA29 · 06-29-2025, 05:36 PM

I don't like to look of the compressor on the engine and the unit hanging under the dash.
Electric AC is the best thing to come out of the electric car fiasco. Electric power steering runs a close second.
I'm going to try this mounted under the back seat and make up ducts to get the air to the front seat. 12,000 btu @ 30-50 amps. A GM single wire alternator has a 100-120 amp output so it would easily keep up.

https://www.ebay.com/itm/29672284735...Bk9SR6DJ49z3ZQ

Gene F · 06-29-2025, 06:09 PM

Interesting idea ModelA29. As someone that used to make my career in the HVAC/R field, and before that in the automotive repair business, just consider that is a long run for the refrigerant. Ducting to the front may be interesting considering condensation, and flow loss of such a small system. I'm not nit-picking, just saying it's an interesting idea. I'd say #8 automotive wire going back there would be a good idea (Jegs).

Do us a favor, and take some pictures after you are done.

Herb Concord Ca · 06-29-2025, 06:32 PM

Model A29, your ducting will be a challenge, like Gene says. You may end up with the evaporator under your tank in the front.

I have Ken Davis A/C in my Slant T/S for 15 years. Ken spent a number of years developing his kit.
You may have some "developing time" yourself in order to get it optimized to your likening.
Good luck with your adventure.

ModelAArmy · 06-29-2025, 08:45 PM

Here is a link to Ken Davis
http://www.kendavismodela.com/

Hitman · 06-29-2025, 09:21 PM

Electric AC systems are the way to go. The Toyota Prius and all Tesla’s have been doing this for over a decade. The length in the line run isn’t an issue. Porsche 356 guys have been doing this for awhile too. Their systems are clean and nearly hidden, but out of the price range for most A guys.

The main issue is the amp draw they require, it takes a big alternator and some modifications to the wiring harness. Not impossible.

rich b · 06-29-2025, 09:31 PM

Besides the current draw of the compressor, you also need to consider the draw of the condenser fan along with the blower fan. Probably need a "real" 130 amp alternator to do it right.

Kurt in NJ · 06-29-2025, 10:28 PM

With the small amount of belt contact on the small pulleys used to spin the alternator fast enough how will it be able to handle the horsepower to make the constant amperage to run the system?
Most alternators cannot make the top amperage output continuously,the output drops off as the alternator heats up.
For those with alternators have you ever tested the maximum output to see if it can supply the rated output?
I think a flywheel alternator could be the answer.

06-28-2025, 09:37 PM	#1
Gold Digger Senior Member Join Date: Nov 2011 Location: Arkansas & Alaska Posts: 685	12 volt air conditioners Been hearing about new 12 volt air conditioners on U-tube. Wondering if anyone has put one in a Model A yet? I know Model A's are 6 volts but I might consider a change to 12 if it was worth all the work installing and if they actually put out enough cool air. The older I get the more the heat bothers me and I drive my Tudor almost everyday.

06-29-2025, 04:32 AM	#2
Bruce of MN Senior Member Join Date: May 2010 Location: VA Posts: 1,807	Re: 12 volt air conditioners I would compare the compressor motor amp draw to the 12v alternator output. My first reaction would be that a belt driven compressor would draw less horsepower than the intermediate conversion to electrical power.

06-29-2025, 04:40 AM	#3
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,842	Re: 12 volt air conditioners A link please. Bruce has a good point. You would have to consider the efficiency of the alternator and compressor motor. The advantage may be ease of installation. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-29-2025, 05:01 AM	#4
Bruce of MN Senior Member Join Date: May 2010 Location: VA Posts: 1,807	Re: 12 volt air conditioners I had saved this from a previous thread on the topic: https://www.amazon.com/Conditioner-U...0D3QKCFK2?th=1 I don't find a spec on current draw.

06-29-2025, 06:42 AM	#6
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,842	Re: 12 volt air conditioners Sponsored Links (Register now to hide all advertisements) The ad does say 3,000 Watts of cooling. If that is what is drawn from the alternator/battery then that would be 250 amps at 12 volts. Tom, above, uses a COP of 1 KW so in that case the average amperage would be 83 amps. This may be a good choice for a boat with a large solar system or Diesel generator and large house batteries but not for a Model A. Here is the link for the Ken Davis air conditioning system: Several people I have met say that they like his AC system and that they don't notice any draw on the engine power. I don't know if his system is still available. My only complaint for his system is that it takes up a lot of room under the tank. http://www.kendavismodela.com/AirConditioners.html __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 06-29-2025 at 06:48 AM.

06-29-2025, 07:24 AM	#7
Badpuppy Senior Member Join Date: Dec 2017 Location: Guthrie, OK Posts: 1,247	Re: 12 volt air conditioners 10,000 BTU would cool a bus. 1K/300W should be enough for an A, but that's still 25A @ 12V, not including efficiency rate.

06-29-2025, 08:56 AM	#9
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,842	Re: 12 volt air conditioners For those who do not know, new electric motors that run off of batteries are permanent magnet AC motors that are driven by a motor controller. The controller puts out variable frequency, multiple phase AC (alternating current), that powers the motor. These are used in all sorts of applications, including model airplanes, for which I am the most familiar. The motors use the rare earth magnets that are super magnetic. For model airplanes the motors are 3 phase. The controllers and motors are super efficient. These motors, and lithium batteries, have almost replaced the glow fuel engines of our youth. Even for large planes like 1/4 scale. The controller frequency, and thus the motor rpm, is controlled by the radio control, so that the motor can be run from zero to maximum rpm with the throttle stick on the transmitter. I believe that the inverter compressors that Brent talked about above has one of these super efficient AC motors. Although it could be another type of motor that oscillates, but is still super efficient. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 06-29-2025 at 09:09 AM.

06-29-2025, 12:46 PM	#11
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,842	Re: 12 volt air conditioners Like my model airplane electric motor. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-29-2025, 01:40 PM	#12
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 2,476	Re: 12 volt air conditioners There is a Model-A chapter in TN some place that a fair number of the members have tinted their windows a little, and installed A/C in them. They mount the condensor under the coach. I know my wife was talking to one of their wives at the national meet once. She said it's not like a modern car, but it's not bad. It does require the high-compression head, at a minimum. Car needs to go 12V with an alternator too.

06-29-2025, 05:31 PM	#13
ModelAArmy Member Join Date: Apr 2022 Location: Mansfield Texas Posts: 55	Re: 12 volt air conditioners I have AC in my car. Ken Davis in Texas sells a kit to install A C in a model A. __________________ Tom in Texas 1931 Coupe

06-29-2025, 06:09 PM	#15
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 2,476	Re: 12 volt air conditioners Interesting idea ModelA29. As someone that used to make my career in the HVAC/R field, and before that in the automotive repair business, just consider that is a long run for the refrigerant. Ducting to the front may be interesting considering condensation, and flow loss of such a small system. I'm not nit-picking, just saying it's an interesting idea. I'd say #8 automotive wire going back there would be a good idea (Jegs). Do us a favor, and take some pictures after you are done.

06-29-2025, 06:32 PM	#16
Herb Concord Ca Senior Member Join Date: May 2010 Location: Concord CA Posts: 755	Re: 12 volt air conditioners Model A29, your ducting will be a challenge, like Gene says. You may end up with the evaporator under your tank in the front. I have Ken Davis A/C in my Slant T/S for 15 years. Ken spent a number of years developing his kit. You may have some "developing time" yourself in order to get it optimized to your likening. Good luck with your adventure.

06-29-2025, 08:45 PM	#17
ModelAArmy Member Join Date: Apr 2022 Location: Mansfield Texas Posts: 55	Re: 12 volt air conditioners Here is a link to Ken Davis http://www.kendavismodela.com/ __________________ Tom in Texas 1931 Coupe

06-29-2025, 09:21 PM	#18
Hitman Senior Member Join Date: Sep 2014 Posts: 820	Re: 12 volt air conditioners Electric AC systems are the way to go. The Toyota Prius and all Tesla’s have been doing this for over a decade. The length in the line run isn’t an issue. Porsche 356 guys have been doing this for awhile too. Their systems are clean and nearly hidden, but out of the price range for most A guys. The main issue is the amp draw they require, it takes a big alternator and some modifications to the wiring harness. Not impossible.

06-29-2025, 09:31 PM	#19
rich b Senior Member Join Date: May 2010 Location: Minnesota Posts: 2,025	Re: 12 volt air conditioners Besides the current draw of the compressor, you also need to consider the draw of the condenser fan along with the blower fan. Probably need a "real" 130 amp alternator to do it right.

06-29-2025, 10:28 PM	#20
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,553	Re: 12 volt air conditioners With the small amount of belt contact on the small pulleys used to spin the alternator fast enough how will it be able to handle the horsepower to make the constant amperage to run the system? Most alternators cannot make the top amperage output continuously,the output drops off as the alternator heats up. For those with alternators have you ever tested the maximum output to see if it can supply the rated output? I think a flywheel alternator could be the answer.