Forum Discussion

flysar's avatar
flysar
Explorer
Nov 23, 2013

Power fluctuation when plugged into AC

9pm last night I saw my neighbor out with his flashlight crawling around his trailer. I asked if he needed any help and he said he hadn't winterized yet (mid 20's the couple days) and he was having electrical problems.

- 1 on board battery completely dead, not a hint of light
- Plug into 110 AC and there is one LED when checking battery health.
- Microwave timer light is on so we know there is AC power.
- Lights are very very dim.
- When he turned the furnace on the lights got brighter and then the blower and lights began to surge/fluctuate.
- Water heater electrical element is working because the water was hot when we drained his tank.

I told him I would help him troubleshoot today with a multimeter not sure where to begin.

Will a bad battery, dead cells, cause this kind of problem?

Any other ideas?
Truck Campers
  • flysar's avatar
    flysar
    Explorer
    Nov 24, 2013
    Not only was the battery bad but the converter also. We got it all heated up and last I know he was going to complete winterization today and tackle the electrical issues when things thaw out in the spring.

    Thanks to all for the guidance, he appreciated it.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Nov 23, 2013
    Don't be surprised that the converter is the problem.........battery is dead because charger section of converter isn't putting out proper voltage to charge/maintain battery and the lights dimming/getting bright is the converter struggling to produce needed voltage.


    With battery disconnected......trailer plugged into 110V AC.....check that converter is getting AC power (outlet it is plugged into or at circuit breaker if hardwired) then check converter output at terminals on converter where battery cables connect........output voltage should be 13.6V DC

    If converter isn't putting out 13.4-13.6V DC it is in trouble.
  • flysar's avatar
    flysar
    Explorer
    Nov 23, 2013
    I don't know how old his rig is but it has the same converter as my 2012 Chalet so it must be pretty new.

    Thanks for all the info and I'll be sure to report back so others might learn something.
  • RoyB's avatar
    RoyB
    Explorer II
    Nov 23, 2013
    For many of the older trailers the on-board converter were of poor design and needed the battery to be connected to stabilize some DC VOLTAGE regulation. Some converters actually were installed with a battery operated relay that would shut it down if the battery became disconnected. With today's Converters and better circuit regulation the 12VDc Battery is not required per say.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Nov 23, 2013
    Most but not all chargers will be OK w/o the battery. A great first step would be to charge and load test the battery. If it's a battery problem all kinds of strange problems are possible.
  • flysar's avatar
    flysar
    Explorer
    Nov 23, 2013
    He had a quick disconnect next to his tongue mounted battery can we just use that or should we remove the battery?

    So technically the battery doesn't even have to be mounted to use AC power, I always thought it did... learned something new.
  • enblethen's avatar
    enblethen
    Nomad
    Nov 23, 2013
    Yes, a shorted battery will cause strange activity.
    Disconnect the battery and see what happens.
    Check the battery for water. It could be dry.

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