House Battery Won't Charge Off Engine But Charges With Generator and Land Power

[squid]

I was wondering what the most likely explanation is for this? The house battery charges fine off generator or land power, but when I drive it's not charging. Is this most likely the isolator, disconnection or some other part? It's a 2012.

Also I was wondering how best to get solar and inverter setup. I have a harbor freight inverter and one new unopened 100W harbor freight solar panel, a 12V extra LiFePO4 battery, and the newused rig I bought has "solar setup" on the readout panel (but no solar currently). If I hire this out could they use the lithium battery somehow? I think it's not supposed to be put in parallel with a lead acid battery. Thank-you

 

[Weight]

The HF stuff is not worth the cost of time needed to mount to a RV. You could set the HF kit up on the ground by following the instructions. This would help you learn something about solar power. What size is the LFP battery? Is that your house battery? Not charging from the engine alternator is one or more of the problems you listed. Unless it is something else, related to the problems you list. Start by checking the wiring between engine and house battery.

 

[DLTooley]

You'll want a volt meter. Isolator's have the reputation of being failure prone, solenoids are the preferred tech - or just a hard manual disconnect. That technique would also work as a testing step, and an interim solution.

 

[highdesertranger]

you have a problem with your isolator/solenoid or whatever controls the house battery charge from the engine. could be a component failure or something as simple as a blown fuse. if we knew what system you have we could give you better info. time to get the multi-meter out and start troubleshooting. highdesertranger

 

[squid]

The 12V LiFePO4 is not in the system on the RV, it's a spare.

 

[squid]

OK I'll watch some youtubes on how to use one of those meters as I do have a new one in a box in the tool chest.  So I guess with the engine running it should detect current coming from the engine to the battery, so I'm guessing I'd unhook the wire to the battery from the engine and just put the red on the - and black on the + from the engine and see if it's charging or how much.  If it is charging...I guess I'll find where the isolator is (is it by the battery or by the engine?, must be along the wire somewhere?) and replace it with this "solenoid" (but which one/kind?  I'll ask as Schucks O'Reilly)....or I'll hire a mechanic if I hit a wall along this logic, don't want to mess up my rig.  She's got a lot of miles but runs perfectly.

Gotta get over my meter-hurdle.

 

[Weight]

Set the meter to the DC Volt scale. With engine (and everything else) off, measure the volts across the battery terminals. Both house and starter. Then do the same with the engine running at a fast idle. You should see an increase in voltage, from whatever about 12.5 volts when off to about 14.6 volts when running. Your volts may vary from that. If so, you are charging. If not, you can follow the wire back to where the volts do show charging. There you will find the problem. It is easier than it sounds.