Adding a 24 volt alternator

[evo45]

This may be a crazy idea but I was wondering if anyone has ever added a 24 volt alternator to a 7.3 powerstroke? If it is possible or if someone has done it please explain how and what you were using it for. I would eventually like to try to add one for a 24v power inverter to run an a\c system on my camper. If there is an easier way to power the a\c system please explain.
Thanks
Vic

[Dirk]

I replaced a set of injectors and injector cups on a 2000 F250. The guy had replaced the trans with one that had the PTO setup. He took apart a honda generator and modded it to be powered by the PTO. Real slick setup and had a cage mount welded to the frame to support the generator. He had a nice bed camper in the back and the generator powered the a/c, lighting, and whatever just fine.


I wouldn't mess with the charging system.

[wiyrs]

mhmm adding a 24V to a 12V system will fry everything.. u can get a dual alt bracket. and put the 24V alt in the 2nd one and just run a power wire from the alt to some batterys in the bed.. wait, i dunno. would it matter if you ground it to the 12V? would i still fry stuff? i dunno.. just buy a generator

[NoRalPh]

Originally Posted by Dirk

The guy had replaced the trans with one that had the PTO setup. He took apart a honda generator and modded it to be powered by the PTO. Real slick setup and had a cage mount welded to the frame to support the generator. He had a nice bed camper in the back and the generator powered the a/c, lighting, and whatever just fine.

Boy I don't see how that would work..... The rpm of the PTO is pretty low. A gas gen-set needs to be turned at 3,600rpm to produce the 60mHz for the AC line. Even a 4-rotor set (from a diesel generator) needs to be 1/2 that, at 1,800rpm.

I guess you could multiply it with gears or pulleys but again, at that point you still have to maintain the trucks rpm to a pretty exact range to produce the proper AC sine wave. - Sounds kinda klugey to me

Also the 12v & 24v systems can share a common ground without trouble but you'd better be sure to isolate the + side!

I too think the easiest way to go would be with a separate generator....

[Dirk]

Originally Posted by NoRalPh

Boy I don't see how that would work..... The rpm of the PTO is pretty low. A gas gen-set needs to be turned at 3,600rpm to produce the 60mHz for the AC line. Even a 4-rotor set (from a diesel generator) needs to be 1/2 that, at 1,800rpm.

I guess you could multiply it with gears or pulleys but again, at that point you still have to maintain the trucks rpm to a pretty exact range to produce the proper AC sine wave. - Sounds kinda klugey to me

Also the 12v & 24v systems can share a common ground without trouble but you'd better be sure to isolate the + side!

I too think the easiest way to go would be with a separate generator....

High idle mod and some kind of gear reducer box used in 'reverse". PTO powered the low side, and the high side stepped up the generator. When the PTO engaged, and the idle stepped up, he said it was within 100-150rpm of the original small engine. He showed me how it worked, and it did work.


12v vs. 24v dc do share a common ground. Problem for me is finding and pricing out the inverter and how much amperage you would need to push.

[NoRalPh]

Originally Posted by Dirk

High idle mod and some kind of gear reducer box used in 'reverse". PTO powered the low side, and the high side stepped up the generator. When the PTO engaged, and the idle stepped up, he said it was within 100-150rpm of the original small engine. He showed me how it worked, and it did work.

Wow, I'm sure it did,,,
Not sure running a 7liter engine at high idle to turn a small AC generator makes a lot of sense though hehe...

[evo45]

My idea was to run a second alternator that was 24v and run this inverter. APS2424 - PowerVerter APS Inverter/Charger with Auto-Transfer Switching You can find them cheaper through google and a couple of people have them in their 2.5 ton 6x6 for electrical power. I would run both batteries for the 24v system under the truck in a cradle with the inverter. Also as others have said the 12 and 24v systems can share the same ground. I think it would be an expensive project but I like this better than running a regular generator for power.

[JSchuricht]

Yes you can. Some higher end motor-homes run a 24v alternator that is dedicated to the coach while maintaining a 12v alternator for the chassis. You can share a ground, just make sure that you never connect the +24v to the +12v. Unlike AC with a common wire and multiple phase, the common wire in DC will have to be large enough for both systems. I would suggest a dedicated ground wire from the alternator chassis to the batterys.

I don't know anything about the inverter you specified, but I would recommend you spend the extra for a sign wave inverter so you don't prematurely kill the compressor motor. Outback inverters while expensive, are my favorites.

[Dirk]

Originally Posted by NoRalPh

Wow, I'm sure it did,,,
Not sure running a 7liter engine at high idle to turn a small AC generator makes a lot of sense though hehe...

High Idle was around 900-1100 rpm. Truck was pretty much all stock. With the gear box and the engine speed around 900-1100rpm, it was about perfect. The whole truck was awesome. It had the tow package and camper package like mine. So with all the weight, the truck sat level. Otherwise, these 2 options make the a$$ end stick up higher than a standard F350.

I have the camper package, (heavy springs, taller blocks), but I use 3in drop shackles in the rear. Now that my truck is a 4wd, the truck sits completely level. If I have more than 2000lbs in the back, I have air bags to level it out. The only problem, my caltracs. I have to adjust them out a bit to allow spring travel.


As far as the 24v setup, find a diesel pusher motor coach and do some poking around. You'll get the idea from it.