Forum Discussion

truepath's avatar
truepath
Explorer
Jan 30, 2016

battery not charging from shore power

I have a house battery charging problem on my class B that I need some help with. Here is the situation: the house battery will not charge from shore power or from the generator, but it does charge when the vehicle engine is running (there is a solenoid connecting the vehicle charging system to the house battery). The generator will run, but only if the vehicle engine is running. The house 120 volt system works with either house power or generator power (until the generator shuts down). I think that either the power switch is not sending power to the converter, the converter is not functioning or there is some kind of continuity break in the wire from the converter to the battery. Suggestions on how to go about isolating the problem would be appreciated. Thanks.

6 Replies

  • Almot's avatar
    Almot
    Explorer III
    truepath wrote:
    I think that either the power switch is not sending power to the converter, the converter is not functioning or there is some kind of continuity break in the wire from the converter to the battery. Suggestions on how to go about isolating the problem would be appreciated.

    Yes :)

    Seriously though, what suggestions do you expect? It's either converter output, or converter-battery wiring. So go ahead and check both. (The "wiring" would include any fuses and switches btw converter and battery). Disconnect the battery and see if there is 13-14V output on converter terminals, with shore power on.

    Could also be wiring btw the shore input and converter, but, since 120V gets through, I would suspect things downstream.
  • Gjac's avatar
    Gjac
    Explorer III
    Check the simple things first. What does the battery read when converter is plugged in? Should be 13+ v what is the output of the converter? Should be 14+ v. Do you have a battery cut off switch or battery disconnect? Is power getting to the switch? Is it getting through the switch when on? If you post back you will get more accurate help.
  • You have it narrowed down. You now need to find the converter to see if it is Getting 110 volts so it can then convert to the 12 volts.

    You may have a 110 volt circuit breaker or GFCI breaker tripped.
  • I had the same problem with my MH a couple of weeks ago. It turned out that the manual disconnect switch in the battery compartment was bad and would not let any power go to the coach batteries.

    As DREWE said in a previous post, it could be the latching solenoid is bad, or a manual disconnect that I mentioned. You can bypass either one by connecting both of the heavy cables together on one terminal. If the coach batteries are being charged after doing that, then you know the switch/solenoid is bad.
  • Check the output of the converter. If your battery is dead or low you should 'hear' the converter trying to charge it.

    Or the simplest is the coach battery needs to be replaced.
  • Does the house 12V system work normally, particularly off of battery power? My guess would be no.

    Often there's a disconnect solenoid (a latching solenoid, so only energized to switch between on and off) between the house battery and the house 12V system. Maybe it's not working or not turned on. If there is one, there should be a bidirectional momentary switch to turn it on and off somewhere. If the solenoid is defective, it can be bypassed by connecting the two heavy power wires to the same terminal on it.

    It would also be good to check the main fuses on the 12V panel and/or the "reverse polarity protection" fuses on the converter. There may be a separate main fuse at the house battery connection or a self-resetting circuit breaker there that would be worth checking, too.