12 VDC vs 24 VDC for a camper build??

[ballencd]

I've got a 1984 M1010 with a 24 vdc electrical system presently. I am wanting to build a camper with heat, A/C, hot water, refrigerator, stove/oven and I have some questions on the voltage I should use.

I have converted the M1010 to an 24 vdc system using two (2) 160 amp alternators with each charging a 12 vdc battery with isolated grounds. The batteries are wired in series providing 24 vdc.

I want this vehicle to be dependable and easily maintainable. If I stick with a 24 vdc system, I can find most of the needed accessories in 24 vdc applications but if one of my alternators goes down I will lose power in a short time. I am thinking I can rewire, fairly easily, to a 12 vdc system and run one (1) alternator for the truck system and one (1) alternator for the house system and end up with duplicate charging systems that can be shared if I have problems. I have not purchased any equipment yet so I can go either way.

Question: Which way should I go? The 24 vdc system would use less wiring and smaller wiring but have no backup. I could source a third alternator and carry it as a spare of course for backup......or I could convert to 12 vdc and have dual systems with a spare always running.

I do plan on solar power at some point which I think would make more sense going the 24 vdc route but can work at 12 vdc also...........Your thoughts?

 

[ITTOG]

Interesting question and one I had pondered a lot. I have never thought about the charging from an alternator though. Can you not get one alternator that outputs 24 volts?

 

[ballencd]

Interesting question and one I had pondered a lot. I have never thought about the charging from an alternator though. Can you not get one alternator that outputs 24 volts?

I probably could but 1) I've already got two (2) new 12 volt alternators. and 2) the military system uses 12 volts for the cab, lights, horn, blinker, and 24 volts for the starter so a 24 volt alternator would not charge the 12 volt system battery properly as far as I can tell. Going 12 volt would require me to buy a 12 volt starter and rewire the existing batteries in parallel vs series as they are now but would allow me to use all 12 volt appliances and one alternator for the start battery and one alternator for the house batteries.....but the solar system would not be as efficient from what I can tell. A 24 volt system would allow me to use the existing starter, more efficient appliances, smaller wires, but not have the redundancy or the 12 volt system....???

 

[ITTOG]

Okay, makes sense. So why not carry a spare 24V alternator (along with all the supplies to change the battery set up), for when a 12 V alternator fails? But I guess that would still present a problem for the 24v starter. When I originally thought about a 24V system, really I was thinking 48V, I was not planning a DC/DC charger. I hadn't even thought about it and see now it complicates things.

 

[ballencd]

I can carry an extra 12 v alternator. They put out 160 Amps each which seems like it would be enough. The first alternator is grounded to the chassis and the second is grounded to the negative of the first battery and the positive of the second battery and the batteries in series put out 24 v. The M1010 uses 24 v for starting but the rest of the truck runs off the first battery at 12 v. I am thinking that solar would be more efficient at 24 v and a lot of the appliances can be bought at 24 v. I think I would like to stay 24 v but trying to charge the house batteries using DC-DC chargers might be troublesome. I might be able to keep the house system separate for the main battery system and NOT tie the house batteries to the chassis but use an isolated ground for the house stuff and put one 12 v DC-DC charger on each battery......???? Does that make sense.. Maybe I could go with (2) 24 v to 12 v DC-DC chargers and charge the house batteries from 24 v...?
I have pulled out the paneling in the box and am starting to deal with the wires. I m a long way from being done.