Small Cabin

Small Cabin Forum
 - Forums - Register/Sign Up - Reply - Search - Statistics -

Small Cabin Forum / Off-Grid Living / can i connect a generator to 12 volt battery
Author Message
# Posted: 21 Jan 2011 01:39 - Edited by: farzan

I have a cabin that is 5x20 ft. On the roof there are five 68W Uni Solar panels that are connected to skyblue 1254XI charge controller. There are two six volt torjan gel batteries. there is a 3000w/12v pure sine inverter . There are 2 computers, printer attached to the inverter. We are going to install a coleman 13500btu air condition that works with generator. I like to use the generator also for backup energy for Torjan Batteries, in case the solars are not charging.
My question is what generator is good for this operation. Can I attach the generator directly to the batteries or i need another charge controller . What is regulated generator. PLease advice.

# Posted: 21 Jan 2011 02:05

Honda inverter generators have proven to be dependable and fuel efficient. I know several people on this board own them

You will need some sort of battery charger between the generator and the batteries to regulate the charge current. The ones from Iota get good reviews and are reasonably priced, get the IQ module

# Posted: 21 Jan 2011 10:15 - Edited by: MtnDon

As Rob_O stated, Iota makes great chargers. Also Xantrex makes a couple models that also have the ability to do the battery equalization charge, Iota do not. Some upper scale inverters have built in chargers; MTL yours does not, but check to be sure.

How much power does the A/C use? Most have a heavy start up draw and that unfortunately is not something that is rated on the spec plate. The generator must be able to supply the surge required to get it started.

You can buy a "start kit" which is an extra large capacitor basically. Talk to a refrigeration pro.

# Posted: 10 Feb 2011 02:14 - Edited by: TomChum

I have a little, quiet 1000W Honda generator, Honda EX1000. These are 'old school' Honda, available for $200-$300 on CL. For $500-$600 (Craigslist) you can get a Honda EU1000i which is pure sine-wave. Or the EU2000i for about $800-900. These sine-wave generators produce a clean output that can run your electronics directly if necessary.

Anyway I use the EX1000 with a microprocessor controlled 25Amp automatic charger. I have one 85W solar panel up un a tree. Just before leaving our cabin after 3 days of winter use, I decided to top-up my batteries. I connected the 25A charger direct to the 12v battery bank. The little Honda pushed 15.4A for about 3 1/2 hours, until the charger's display said "full"!

My Honda EX1000 (and the EU1000i and others) has a separate 12v battery charge output that produces 8.5Amps (but there is no information display telling you what's happening). I would have no idea if the batteries were left undercharged, (or overcharged). It is good to know, when you leave your cabin that your batteries have a full 100% charge. Batteries will last the longest when they are fully charged all the time.

Running the Black&Decker charger from the 110v outlet, I was able to charge at 15.4A (almost twice the speed at 8.5A) and get the additional benefit of the automatic charge controlling the rate; and also the charger will tell me when the battery is full. It was charging at 15.5volts at 15.4Amps which equals 238Watts, easily within the capacity of the little 1000W generator.

To charge faster, I bought the new 71227 Diehard 40Amp Microprocessor controlled automatic charger (it's $99 new!). You can see it here. I have not yet tested this new 40A charger.

You might check on the specs of your inverter, in case it includes a battery charge function. My 2000W inverter does charge batteries at the rate of 5.5A which is pretty slow and takes a lot of gas. Note that 5.5A is ~1/3 the rate of what my 25A B&D was able to push into the batteries (15.4A). This would take 3x as long to do the same charge. At 5.5A rate, I would have had to run the generator (3x) 3 1/2 hours = 10.5 hours to get to "full" charge.

To recap... I plugged the 110v, 25A Black&Decker charger into the 110v generator outlet, and connected the charger's clamps directly to the battery 12v terminals. My charger indicated 15.4Amps charge rate, for 3 1/2 hours until the display said "FULL".

# Posted: 10 Feb 2011 09:27

Now that's what I call double-duty! Cool idea.

Your reply
Bold Style  Italic Style  Underlined Style  Thumbnail Image Link  Large Image Link  URL Link           :) ;) :-( :confused: More smilies...

» Username  » Password 
Only registered users can post here. Please enter your login/password details before posting a message, or register here first.