Charging Your House Battery With 120v AC

My Vandwelling friend had a common problem.  They had 100 watts of solar for their house battery but needed to fix the Combiner that charges the house battery from the engine when solar is not possible.

On my way to meet my friend, I didn’t know what the fix would be for resolving the combiner (see separate post on how I fixed the problem), so I confirmed that they had a 120 v inverter first.

When I arrived to check the Combiner circuit, my friend had a small inverter like the one in the Amazon picture, above.

Since I needed to do some research on the Converter circuit, I had stopped at Harbor Freight in Tucson in the way to Ehrenburg, AZ and purchased an extension cord and small lead acid battery charger / maintainer that would work with a 4 amp 120v charger.

I bought this 12v lead acid battery charger, as seen in the Harbor Freight screen capture above.

I also bought a short 10’ heavy duty power cord to match the charger.  Again the picture above is a Harbour Freight screen capture photo.

The charger comes with SAE connectors so I chose the fused terminal lug adapter above, in the Harbor Freight captured photo, to connect directly to the battery terminal lugs.  

My friend plugged their inverter into the dash socket while running the engine and then plugged in the charger.  As it turned out the power cord and charging cord was long enough for the charger to plug directly into the inverter and the 10’ extension cord wasn’t needed.

So, what is my friend to do with the unused extension cord?  They offered to give it back but I said keep it.

See, I knew they visit a friend’s house in the summer and may not get enough solar but possibly they could plug the extension cord into the house wiring and feed the charger that way to keep the battery charged when parked and not driving if there is no solar due to trees, or clouds.  It’s a great backup even if you have a friend with extra solar to share.

With this setup my friend has 3 ways to charge their house battery.

1. Solar

2. Combiner once I fixed it.

3. 120v from inverter with vehicle or shoreline when parked at a friend’s house or campground with power.

This is how my 12v charging system works in my camper, only it’s for my LiFePO4 battery system using lithium solar charge controller, Lifepo4 120v Charger, and fixed voltage charger from engine specified by Bioenno, my LiFePo4 battery supplier.

Note: I am not affiliated with Harbor Freight, Amazon, or Bioenno.  My post is an unbiased look at how I solve small vehicle house battery charging problems.  There are more than one way to address charging and my suggestion is highly cost effective over damaging batteries prematurely due to under charging.

PS.  I have already written about fixing the combiner circuit for my friend.  This supplement blog was actually provided first while I researched the combiner circuit problem, and the days that went by before my friend and linked up our locations again.

Brent

macaloney@hotmail.com