# Best way to charge batteries when no solar



## JohnP (Sep 1, 2010)

I've got a couple of options for charging the batteries when solar won't cut it due to cloudy days or on extra heavy load days. I'm wondering which would be best and how to go about it. I've got a small 6 amp Schumacher charger and the converter/charger that came with the 5th wheel. Either would be powered by a genny. I'm not sure which one would be best and there's no ratings on the converter/charger. I'm also wondering where in the system to connect one or the other. Directly to the batteries or through the charge controller? The 5th wheel charger jumps up over 16vdc when connected, the schumacher slowly crawls up over 15vdc so both will go above the bulk setting on the controller. I have a disconnect for the panels so I'm thinking the best way would be to go through the controller to get the safe, high tech, 3 stage charge. Just not sure if it's a safe thing to do. I don't see why it wouldn't work though. It's DC power and the C40 is rated up to 125vdc input. 

The 5th wheel converter has two outputs, one for charging and one 12vdc so that could be handy. I could put a transfer switch in there to power the house on the 12vdc instead of the batts and charge the batts quicker with no load on them via the 16vdc running thru the C40.

Eenie meenie minie mo, which way should I go?


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## 12vman (Feb 17, 2004)

Your C-40 will monitor the battery voltage for you. Just connect direct to your battery and watch the green LED. When it goes solid green, your battery is charged.


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## PD-Riverman (May 24, 2007)

JohnP said:


> I've got a small 6 amp Schumacher charger and the converter/charger that came with the 5th wheel. Either would be powered by a genny.


What size is your battery bank? Unless it is real small, I feel that a 6 amp charger would be way to small to run on a generator to charge a good size battery bank-----Would use alot of gas for a small charge. Example I have a 45 amp "switching" battery charger and it only draws around 5 amps and it takes hours to bring a bank of 6, 6 volt batteries back up to full charge. 

I would at least get a 20/30 amp charger. Just my opinion.


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## Windy in Kansas (Jun 16, 2002)

Along similar lines----could a C60 charge controller be used with a small gas engine driving a 40 amp single wire auto alternator to properly charge a small bank of several batteries?

How do watt hours consumed compare to replacing them via a charger? 
Ex: 360 watt hours used, input to replace---12 V X 30 amps going back in. I assume that the alternator would need to be run for a little over 1 hour because of loss due to inefficiency? I'm referring to the 360 watt hours as the total amount draw via an inverter, with actually used as less because of inefficiency in the voltage conversion. 

I've always wondered about that. Don't alternators produce higher amps when first charging an AUTO battery IN A CAR, after starting the engine is complete and then taper the charge off to lower as the battery becomes charged?

What I'm getting at ultimately it seems to me that for such recharging an alternator driven by gas engine would be better than using a generator and charging via a 110 volt charger.


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