Ridiculous idea?

[Dorfie]

I have been attracted to the all electric air conditioner system to install in the RV 10. However, it needs a 24V system, which I am not really interested in. Is it possible to have a 24V alternator, two 12V batteries in series which will supply 24V to AC system. Then tap the two 12V batteries in parallel to supply 12Vpower to rest of all aircraft systems? I think it sounds silly and far fetched that it will work (been stalling posting this for a long time), but would like to get some understanding why and why not, what is possible and what not. Just thinking!!
Thanks.
Johan

[Mike S]

Pretty sure you can do such a thing, using the right diodes.

The "right diodes" may be a bit of a problem??

[Bill.Peyton]

There is no reason you could not consider a 28V system for your aircraft. Most avionics will accept 28V, If you were planning on a Vertical Power system, I don't believe that would work. The real issue is designing a system with an essential bus. It sounds like a lot of batteries. It's not a far fetched idea.

[flyeyes]

Originally Posted by Dorfie

I have been attracted to the all electric air conditioner system to install in the RV 10. However, it needs a 24V system, which I am not really interested in. Is it possible to have a 24V alternator, two 12V batteries in series which will supply 24V to AC system. Then tap the two 12V batteries in parallel to supply 12Vpower to rest of all aircraft systems? I think it sounds silly and far fetched that it will work (been stalling posting this for a long time), but would like to get some understanding why and why not, what is possible and what not. Just thinking!!
Thanks.
Johan

I think you can do it, but what systems are you worried about needing 12V?

Most modern electronics and avionics will run on anything from maybe 10 to 32 volts without complaining.

[David Z]

I would just use a power converter. There are several different options available on Aircraft Spruce. 12-to-24 and 24-to-12, depending on which way works best for you.

[Ron B.]

I don't think it would be advisable. One of your batteries would have more load than the other and that would cause problems. I build boats for a living and this set up would be great for us, but we have to use converters .

[rv7charlie]

It takes a lot of grunt to run that a/c. If you don't want a 24V system for the plane, why not add a 2nd alternator regulated at 24 V & AGM battery(ies) that run nothing but the a/c? With proper switching network & a 24>12V converter, it could become your backup supply for an 'essential' bus to run avionics, etc in the event of a main 12V system failure.

If you haven't done it already, I'd suggest signing up for the Aeroelectric email list. A lot of this kind of stuff gets covered there.

Charlie

[BobTurner]

What you described will not work. You cannot have 2 batteries simultaneously in series (for the ac) and in parallel (for the aircraft).

[BillL]

Too many amps to run an electric compressor at 24/28 volts, if that is what you have in mind. Big wires, big switches, big batteries and short run time.

Heavy batteries, unless you want to use LiO Polymer.

A standard belt driven compressor system would be much less weight to actually keep the cabin cool.

Happy hunting for a "cool" solution.

[pierre smith]

I have the Harbour system in my Air Tractor running two 24 volt (standard) batteries. It draws 75+ amps and is hard on my starter/generator, but then again, so is 95? under a helmet, all day long.

Call Harold Harbour in Texas for advice or his son, Scott 806 879 2392.

Best,