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John_S2's avatar
John_S2
Explorer
Jun 20, 2013

Both Batteries went down on me??

I was just using my Class C coach battery on extremely light load, refrig starter, and detectors and water pump.... for one day and I noticed I was at the low point on my charge indicator.... got through the next day okay with refrig, etc. but then went to start the motorhome to go home and the battery on the Ford V10 was also wasted. Just got a clicking sound.

Tried the emergency start routine but that did not help as both batteries were down. Had to call Good Sam ERS for a jump start. First time for this...

What happened ? I figure I may have damaged my coach battery over the winter by hooking up the trikle charger improperly but did not expect a problem with the chassis battery. I did not think that the coach would draw power from the chassis battery when the coach battery got low. Am I wrong?

8 Replies

  • enblethen's avatar
    enblethen
    Nomad
    Jun 20, 2013
    Why did you use a trickle charger? Your converter should be keeping coach batteries charged. A trickle charger would be normally connected to the chassis battery to keep it up. Older converters can over charge the battery causing loss of water in battery. Check to see what make and model of converter.
    Some coach manufactuers use the Ford trailer power to isolate the different systems. You need to see what isolation unit was used on your rig. Many diode based are in a blue or silver colored box about 4X5 inches with any where from 3 to 5 terminals.
  • John_S2's avatar
    John_S2
    Explorer
    Jun 20, 2013
    To clarify.. the refrig was running on propane. Only used the battery for the periodic ignition needed. The chassis is a Ford V10 1999. I only had the coach battery hooked up to the trickle charger in the basement over the winter. The chassis battery was left in the vehicle and appeared to be working fine up to yesterday. The two batteries have not been hooked up together. The coach battery is hooked up under the step going into the class C. I just checked it and found it and found that it was really low on water which is strange as I had topped it off in the early part of May. Do not know why the
    water disappeared??

    I have added a lot more distilled water and am charging the coach battery overnight to see how it is tomorrow.
  • MrWizard's avatar
    MrWizard
    Moderator
    Jun 20, 2013
    I was just using my Class C coach battery on extremely light load, refrig starter, and detectors and water pump.... for one day


    what is a fridge starter

    the electrical 'Control' system draws milli-amps

    how ever the DC 12v mode draws 30amps
    never run the fridge on DC unless your engine is running

    always use LP
  • HiTech's avatar
    HiTech
    Explorer
    Jun 20, 2013
    weathershak wrote:
    If you have the trickle charger wires hooked to both the coach and chassis battery, then they are no longer isolated.


    This is a very good point - was the trickle charger wired to both the house and chassis batteries in parallel? Is it still wired in even if not plugged into AC power? It is pretty easy to unintentionally bridge the two banks and discharge both doing this.

    Jim
  • enblethen's avatar
    enblethen
    Nomad
    Jun 20, 2013
    You need to identify what type of battery isolator system your rig has. A Diode based unit could have bad diode allowing current flow from chassis battery to feed coach system.
    There is a problem in the system. What chassis is your rig on?
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Jun 20, 2013
    Group 65 batteries are not noted for their robustness. We figured a lifespan of 4 years was about it. Even a 200 ampere battery tester is better than nothing to do a checkout before each season or you detect or sense something isn't normal.

    Assumptions lead to service calls or a sunburned thumb.
  • weathershak's avatar
    weathershak
    Explorer
    Jun 20, 2013
    If you have the trickle charger wires hooked to both the coach and chassis battery, then they are no longer isolated.
  • donn0128's avatar
    donn0128
    Explorer II
    Jun 20, 2013
    Bad isolator could have caused the mo start problem. As for the batteries, how old are they? Take them out, fully charge them then take them for a load test. That way you will know for sure what is going on.

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