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Mikeborny's avatar
Mikeborny
Explorer
Apr 12, 2014

aux. batteries won't charge with shore power

I drained my aux. batteries and main battery last fall. The aux. batteries will charge after running the generator but not while connected to shore power. They actually drain completely after I connect to shore power.
I had a Ford dealer check the batteries and they replaced the main battery and said the aux. where ok. I had a full charge this morning, but after connecting to shore power, they are drained completely. Am I best replacing the batteries or is there another potential problem I am missing.

I have a 2011 Fleetwood storm 32bh. the Aux. are 2 6v batteries.

25 Replies

  • Mikeborny wrote:
    Yes, when i shut off the aux. power switch while connected to shore power all the lights go out? I am a novice when it comes to this, but I thought the shore power would bypass the aux. batteries.


    OK, you stated that when you run the APU (Generator) the Aux (call them Coach and call the Main chassis from now on), the Aux(coach) charge. But NOT on shore power. That does NOT make sense. The only difference between Shore and APU is WHICH is supplying 120 power to the RV, IF the APU supplies power to the RV and the Power Converter(the 12 volt charge appliance in your RV) is operating, then it will also on Shore Power. The APU does NOT charge anything. It has no charger, but supplies 120volts to the RV so your Charger (power Converter) does charge. Yes, you are missing something. Connected to Shore Power, (with bad or NO batteries) you will still have 12 volt power in the RV. How long did you run the APU to "charge" the batteries? It would take at least 6 hours or more to charge a dead or low battery bank, from the APU OR from Shore Power. Now, "some" RV's if connected to Shore Power (or APU), the "Aux Power Switch" (battery disconnect) if OFF, will still have 12 volt power to the RV(the power Converter), but the Battery disconnect will not allow 12 volt power to keep the Aux batteries charged and some OEM's connect the LP/Co detectors direct to the batteries and THAT load will drain the Aux batteries. A quick test to verify this is to unplug the Shore Power cord and IF the 12 volts goes dead in the RV, the Aux switch is indeed OFF. Doug
  • Your lights are connected to the 12V system and your aux batteries and converter supply power when the switch is on. If you have the switch off, no power is available for your 12V system and the converter must be disengaged also.
  • Yes, when i shut off the aux. power switch while connected to shore power all the lights go out? I am a novice when it comes to this, but I thought the shore power would bypass the aux. batteries.
  • Do you have the battery disconnect switch on?
    Usually by the entry door.
  • hummmmmmmmmm......I had the same type of problem and it turned out to be a circuit breaker that had been tripped. The breaker was found hidden up in the corner of one of the outside storage bins. hope this helps

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