12V DC Generator

[Wbago97]

Thanks for replies and I just want to update my thoughts:

-I already have the 5000W inverter/charger and 1000Ah batteries installed. I have 720W of solar that I can expand. That decision is already made even if an external smaller generator for night use is cheaper.
-I already have the 6500W Onan generator to use when I most need it as well as to recharge the batteries.
-Supplementing the batteries for day use (and night where allowed) is the last decision point. That doesn't require 5000W continuous, maybe just 1000W.

Originally Posted by twinboat

If this was fesable, someone would be doing it.

That's why we post and ask

[jcussen]

While I have never used it except for testing, have a little 800 watt inverter generator that will power a 40 amp battery charger. It burns about a gallon every 12 hours and is pretty quiet. Figure if it rains for a week, and my big generator goes down, can still put some charge on the batteries.
https://generatorpowersource.com/rev...ble-generator/

[153stars]

Originally Posted by tfryman

Or you could buy and use a 2K inverter generator to place on the ground to help keep your batteries charged. Either connect it directly to the converter or in conjunction with a stand-alone battery charger. Then you won't need to worry about connecting welding cables to your DC generator.

Ding.ding .ding. Only burn gas needed to keep batts up . once running AC probably 8-10 amps

[twinboat]

Originally Posted by 153stars

Ding.ding .ding. Only burn gas needed to keep batts up . once running AC probably 8-10 amps

A 10 amp draw at 120 volts is 100 amps at 12 volts. Add the inefficiencies of the inverter and you need a large charger to maintain the battery bank.
That size battery charger may draw close to the max output of the 2000 watt generator ( depending on its effencey ). There goes the gas burn rate.

[ScoobyDoo]

Is your RV diesel powered? Rig Master ad claims 24000 BTU cooling, 6000 watts of 120V ac, and 60 AMPs for battery charging. And average fuel consumption of quart a hour...

[Wbago97]

Originally Posted by ScoobyDoo

Is your RV diesel powered? Rig Master ad claims 24000 BTU cooling, 6000 watts of 120V ac, and 60 AMPs for battery charging. And average fuel consumption of quart a hour...

No it's gasoline

[ScoobyDoo]

Originally Posted by Wbago97

No it's gasoline

Ok. But the idea of using the engine to drive the A/C compressor still stands. The compressor designed for auto use would work. Add a small alternator, to replace the 12V used to engage the compressor clutch, and the fans that move the air. Maybe a larger alternator, driven thru another e-clutch, to put a big charge in batteries if needed. If you set it up to run the big alternator or the compressor, you could design around a smaller engine...

[Soppy]

Originally Posted by Wbago97

I am curious if anyone has used a DC generator with an inverter instead of an AC generator. This can be as simple as a small gas (lawnmower) engine with an alternator.
I have a 5000W inverter than can run my roof air conditioners as long as the batteries (1000 AH AGM) have the juice.

If you can find a good direct drive DC generator that will produce around 200amps , it will work. If you are planning a vehicle alternator and belt driving it to a gas engine , it will work , but not very efficiently.

Running 1 A/C unit will require about 150 amps @ 12 volts. You will require very large heavy cables (3/0 copper) to connect the generator to the batteries as well to minimize voltage drop.
Your best bet is to get a small 2000 watt inverter generator and a charger/converter or inverter/charger that you can set the input amp limit to charge your batteries.

[ScoobyDoo]

Originally Posted by Soppy

If you can find a good direct drive DC generator that will produce around 200amps , it will work. If you are planning a vehicle alternator and belt driving it to a gas engine , it will work , but not very efficiently.

Running 1 A/C unit will require about 150 amps @ 12 volts. You will require very large heavy cables (3/0 copper) to connect the generator to the batteries as well to minimize voltage drop.
Your best bet is to get a small 2000 watt inverter generator and a charger/converter or inverter/charger that you can set the input amp limit to charge your batteries.

Back in the early '70s I had couple off gensets designed for jumpstarting mounted on my tow and service trucks. Have burned tons of illegal substances, before and long after, so I don't remember much. Each had 2 generators. I do remember that the old trucks that used series/parallel switches, started on 24 V hook to one pair, pull the caps off battery. In a few minutes, they would start to boil. Cut power, move cables to other batts, power on, hit the button.
Likely that would have the output meet OP's demand, but not trouble free or quiet IIRC...

[Wbago97]

Originally Posted by Soppy

If you can find a good direct drive DC generator that will produce around 200amps , it will work. If you are planning a vehicle alternator and belt driving it to a gas engine , it will work , but not very efficiently.

Running 1 A/C unit will require about 150 amps @ 12 volts. You will require very large heavy cables (3/0 copper) to connect the generator to the batteries as well to minimize voltage drop.
Your best bet is to get a small 2000 watt inverter generator and a charger/converter or inverter/charger that you can set the input amp limit to charge your batteries.

Thanks, I already have 2 each (both positive and negative) 2/0 cables attached to inverter/charger from the battery bank.

[twinboat]

Originally Posted by Wbago97

Thanks, I already have 2 each (both positive and negative) 2/0 cables attached to inverter/charger from the battery bank.

So your running dual 2/0 cables, for a total of 4 to the inverter ?

[Wbago97]

Originally Posted by twinboat

So your running dual 2/0 cables, for a total of 4 to the inverter ?

Yes sir