Want to add second generator/alternator to engine, need info ??

[scanzel]

I would like to add another small generator or alternator to my 8V92 to charge my battery bank while driving. The problem I see is what would I need for cables from the generator to the battery bank which is located in the first front bay on passenger side. This is almost the full length of the bus. How many amps would be good, my battery bank is 8 agm connected in series for 24 volts 400 ah. The only large item that would probably be running on ac is the house refrigerator everything else is either 12/24 volts.
Inverter is 4000 watt magnum. Thank you.

[bevans6]

My first thought is that I think the Prevost is 24 volt for the bus alternator, why not just charge the house bank from the bus alternator.  That's what I do and it works fine.  Anyway, off the top of my head I would suggest a 100 amp 24 volt alternator and 0 gauge wire from the alternator to the battery, and use the chassis for ground return.

Brian

[Oonrahnjay]

My first thought is that I think the Prevost is 24 volt for the bus alternator, why not just charge the house bank from the bus alternator.  That's what I do and it works fine.  Anyway, off the top of my head I would suggest a 100 amp 24 volt alternator and 0 gauge wire from the alternator to the battery, and use the chassis for ground return.
Brian 

     I was strongly steered towards adding a 12V additional alternator (the guy doing electrical work was used to big sound systems that eat up a lot of 12V powerm my only 12V loads are a NovaKool fridge, about 50 watts continuous and led interior lights, about 7 watts each) -- the start system on my bus is 24V.  I used a 90 amp 12V "one wire" alternator (i.e. about 40% of the amps that Brian suggested) and 0 gauge "hot" wire with chassis ground.  It worked well - I had two "pretty good shape" 8-D batteries in the shop so I wired them in parallel for 12V to get the system running.  To match it, I used an Outback 2K 12V - 120V inverter.  If I had to do it again, I'd either run a 24V system off the main alternator or add a second (for redundancy - "back up") as Brian describes.   I'd also use a Victron 24V inverter, but that's another story.  I'm not sure if I'd use a 24V - 12V converter or a Vanner for 12V loads but that's another issue, too.

[bevans6]

Steve said his house bank is 400 ah at 24 volt, hence my two suggestions.  There are other ways to get there, both for 24v and for 12v.  Redundancy is a very good thing - I have lost both the alternator and the bus battery bank at different times, so I know it happens.  I was able to run without the alternator for the rest of that trip, and I just disconnected the bus batteries and ran off the house bank when that happened.  The wonderful thing about a mechanical engine is it doesn't need electricity to run, just to start...

[jackhanow]

On my five I installed a GM style marine 300 amp alt. Made a simple bracket to mount it to the lavatory frame hooked directly to 4 6 volt batteries on the same frame work and ran o cable to the ac box where I have 4 more. I also had my bus generator fail on the road and had to rig up a make shift 24v system by hooking the 12v bank to my one battery and used my little generator with a 12 v 12 amp charger built in to charge the other battery. Not much else you can do in the middle of northern Nebraska.

[TomC]

As long as you can make a mounting bracket for the new alternator, we were selling new 160amp 12v alternators for about $160. Good Luck, TomC