12 volt inverter

[Lester]

We are converting an MCI 102A3. Is there any way we can use a 2500 watt inverter that is 12 volt? The bus is 24 volt.
Les

[TomC]

Yes you can.  Essentially you make a whole new system.  Many converters do this for the house systems since most are made at 12 volt.  You can mount a 130 amp 12v alternator (you can get them brand new for around $250.00 from truck dealers.  Get one with the regulator built in) on your engine and feed directly to the bank of deep cycles for the house.  Then the 12v inverter will be powered through those batteries and if the inverter has a charger built into it (which it should) be able to charge those batteries while hooked up.
The one advantage to staying with 24v is that you can get a 4000 watt inverter.  Course you can also stack 2-2500 watt 12v inverters also.  Good Luck, TomC

[Ross]

Yes you can.  Essentially you make a whole new system.  Many converters do this for the house systems since most are made at 12 volt.  You can mount a 130 amp 12v alternator (you can get them brand new for around $250.00 from truck dealers.  Get one with the regulator built in) on your engine and feed directly to the bank of deep cycles for the house.  Then the 12v inverter will be powered through those batteries and if the inverter has a charger built into it (which it should) be able to charge those batteries while hooked up.

This is exactly what I did.  I have a Xantrex RS3000 inverter.  If I had it to do all over, which I may soon enough, I'd go with a 4024 and keep it all 24V.  It's easy to get 12V from the 24V bank with an equalizer or converter.  The advantage to going with the 4024 is you already have the alternator capacity to keep up with 2 AC's running.  I can run 2 AC's on my RS3000, but the 140A alternator is just enough to keep up with one.  If I run two, I pull down the battery bank.  Because I can't run 2 AC's down the road, I usually just run the genset.  I don't know if running the genset or using engine horsepower is more efficient, but I know running the genset doesn't rob HP from the engine...and I need all I can muster up.

Ross

[TomC]

Ross brought up an important idea.  When I first bought my inverter, I was going to stack two to make 5000 watts, which would have easily powered two roof top A/C's going down the road.  The gal that sold me the inverter (it was her own business) asked if I had a Diesel gen, said yes, and she said just to run the gen when A/C was wanted-rather than selling me another inverter!  Personally, we should think of the inverter as a standby intermittant power source for such things as microwave, coffee maker, stereo, TV, small heater, water heater-all resistance loads without the high starting loads that motors have.  Yes I know the inverters can do this, I just believe that electric motors, such as A/C's (the biggest loads we have) should be powered by a gen that has good starting surge.  And considering how long the Kubota, Isuzu, Yanmar, type engines last loffing along at 1800rpm, I just use the gen.  Good Luck, TomC

[Buffalo SpaceShip]

My conversion (not done by me) has a completely separate house system that's 12v and alternator. Like Ross, I too would opt for a 24v inverter if I had my choice, since the wiring is smaller, has less voltage drop, more powerful inverter choices, AND offers parallel charging of house and coach batts. I would also use as many AC-powered house lighting and appliances as possible, and forgo a lot of the RV DC lighting and convienience items. You can even find 24v water pumps now. That leaves maybe a handfull of 12v devices you could use a converter or equalizer to run.

Just my $0.02,
Brian B.

[RJ]

Les -

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