Technical Air conditioning for a 6 volt system

A friend is buying a BEAUTIFUL 1949 Buick Sedanette coupe that is all stock with 6 volt system. Since it's black and we are in Texas, he asked if there was a way to install some sort of under-dash air conditioning; perhaps by adding a 12 volt alternator and battery while still keeping the 6 volt generator. Anyone have any experience with doing something like this or know who we could talk to?
Thanks,
Mike in Texas

 

I would say maybe have him talk to vintage air?

 

New cars in America have a new refrigerant, R-1234yf - from 2021 onward as I understand it. So you might as well get a system that has the latest cool juice, too. R134a will be gone in 3-4 years...

 

From what I've read, R134 will be around for service for years, it just won't be used in new cars anymore. It's not banned like R12 was, just not in factory new units.

As to the original question, you would need a 12 volt alternator and a battery, and you would have to have a separate harness dedicated to the 12 volt system. One of those mini alternators would probably be easy to hide low on the motor, and a lawn tractor battery would probably have enough amps to hold the AC clutch in and power the fan blower.

 

If you have the room why not add a secondary system? May need to keep grounding for AC unit isolated (use wire rather than chassis ground).

 

63A alternator, powering two 6V batteries back to back, with the car split off one and the A/C across both?

 

My concern would be if the existing electrical system is positive ground, which is pretty typical of 6V systems. Virtually all modern 12V alternator systems are negative ground, and having both positive and negative polarity power impressed on the grounding system could have detrimental effects on any electronics in the 12V charging and AC systems. If it were possible to fully isolate the 12V system it would work, but as virtually all alternators and compressors clutches get their ground through their metal parts (as well as probable other components), this would be very tough to do. I'll be very surprised if any AC supplier will approve this.

Best bet would be to convert the whole car to 12V IMO and install an alternator in place of the generator.

 

Cars with 6 volt systems had AC back in the day. If you can get a 6 volt compressor clutch it should work fine. 12 volt clutches draw around 4 - 6 amps, so a 6 volt clutch probably draws around 10 amps. You would probably be at the generator's limit if you ran the AC and the headlamps.

 

Isn't Buick of that era negative ground?

 

https://www.etrailer.com/question-318532.html

 

I sit corrected. Thanx.

 

Run 2 6v batteries ... 6v for the factory stuff; 12v for the add-ons.

 

AC? We don’t need no stinkin AC.

…..then again, I don’t live in Texas either. Good luck on your project.

 

Could he run a powergen alternator to help with the amps needed?

 

Can’t help you with your 6V question but if it was mine I’d convert it to12V neg. ground and get a unit from VintageAir.

 

This ^^^^^ is the logical answer. Converting to 12v is a lot easier than adding a separate charging system.


But If the OP wants to keep the 6 volt system it is easy to set up 2 batteries so they are "in series" to provide 12v ONLY when the A/C is on.
Then they switch back to "in parallel" when the A/C is off [for charging]
I can post a Schematic of this ^^^ if you want to pursue this "dark path"

I did ^^^ a similar system to provide 24v to my Lucas starter motor when cranking, and soon as I released the starter button the 2 batteries charged together [in parallel]

In the end I ditched it all for a Denso starter [fighting the losing battle with weight on a race car]

Back on subject , The A/C only draws power for the fan motor and the Clutch solenoid.
You could simply wire in a 6v to 12v step up "Buck" converter for the A/C .

But I would test the clutch solenoid out on 6 volt first it is only an electromagnet [like trailer brakes]
Trailer brake work on any voltage ,so maybe the Clutch Solenoid will also

 

YES

Ben

 

Hey there. I'm in a similar situation keeping my car 6 volt while running 12 volt air ride. I have 2 Optima batteries run in series to power it all. But seems the second battery doesn't charge as well as the primary... you mentioned them switching back and forth from series to parallel... How would I wire that up? Thanks for your help. BTW I'm 6 volt positive ground if that makes a difference.

 

You can buy a dc-dc converter very inexpensively. Just get a 6v to 12v converter with enough amps to power your AC. Look on ebay.

 

Saw an old Buick at a car show last year. It had the straight 8 and a/c. It was beautiful but of course, I didn't take notes. Pretty sure it was converted to 12 volt.

 

I see this is an older post come back to life.

Putting different loads on batteries (in series) with one charger can also lead to overcharging/undercharging on the individual batteries. I’ve done this on 32 volt marine systems tapping off 24v and 16 volts for small, intermittent loads. That lets you get away with it, but you need to watch the batteries. That’s what you’re seeing from the air ride compression load.

You can use relays as was described above, but you’re going to need relays to handle the loads involved and it’s probably not as simple as a 12 volt conversion.

 

Well, @miker98038 Ill bring it back to life too. I thought I was going to ask a question that nobody else asked and when I did a search I see the OP beat me to it. So, bump for the question: any other options for AC on a 6 volt negative ground system?

 

I’m running into this problem with my woody and it’s 6v positive ground. I’m just going to bite the bullet and spend the money it takes to convert it to 12v and try my best to make it look close as I can to a factory install if they did that.

 

If one of the AC vendors can't come up with a 6 volt unit. Two thoughts run just the AC off a 12 volt deep cycle battery in the trunk. I've got two big 12 volt deep cycle batteries in my boat, one to run the engine with and one for the "house" battery. One of those batteries would probably power the compressor coil and the blower motor for a good number of hours before needing recharging.

Second idea would be to add a separate 12 volt system with alternator and 12 volt battery that is totally isolated from the 6 volt system.

 

I just saw a you tube video where a guy put a 6 volt positive ground AC on a 1951 Nash 6 cylinder. It was pretty cool. here is the link: Modern AIR CONDITIONING....on a 6 VOLT CAR?! The only thing I didnt get was the reversing the polarity on the compressor

I am thinking for an early Chevy, Ill take a chance and get the compressor like he did and then the volt step and try it.

 

With my luck I’d fry the compressor But I’m going to check it out to see how he did pull it off.