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rastaman33609's avatar
rastaman33609
Explorer
Aug 20, 2014

TC Battery infomation over load

I have just spent the past 3 hours researching wiring info to charge the TC battery from alternator. I have already wired the truck a Dodge 3500
using #8 wire which some info suggest is 'good enough'. I only have 2 6 volt batteries. If I use 40 amp fuses that are rated for #8 wire I am wondering if they will blow because of higher amp draw by the TC batteries.
ALSO..my solenoid is wired to activate when the key is switched on...what is going to stop the starter from trying to draw from the TC battery to start and blow the fuses???
I am totally confused now. I know #8 wire is not as good as #2 however I have read in several posts that the difference is minimal.
Using #8 wire what fuses should I use at each end?
Will I need to wire the solenoid differently?
Thanks
Truck Campers
  • rastaman33609's avatar
    rastaman33609
    Explorer
    Aug 20, 2014
    If I put a light on the camper side of the solenoid to indicate charging, wouldn't that light get feed back from the TC battery even if the fuse on the truck side of the battery is blown?
  • time2roll's avatar
    time2roll
    Nomad
    Aug 20, 2014
    How much charge do you expect? I think you will be lucky to get 20 amps so you need a 5+ hour drive to really bring a low battery up to 80/90% charged.
  • AnEv942's avatar
    AnEv942
    Nomad
    Aug 20, 2014
    Fused at wire rating-
    mine, 10ga, is fused at 30amps-never blown a fuse.
    Batteries are not going to 'pull' higher amps.
    What youve planned should work.
    I would though recommend adding a toggle switch to the ignition control wire feeding solenoid. So that you can manually disable/enable.
    I dont engage mine until Ive been driving a while after starting-my primary want is truck charges its batteries-then camper. I have an amp gage on my aux charge line - after starting, if solenoid is engaged, Ive seen the reverse flow camper to truck, but only within the first few minuets after starting.
  • enblethen's avatar
    enblethen
    Nomad
    Aug 20, 2014
    The relay should not be energized in the start mode, only in the run so it should not be pulling off the camper battery.
    It is going to be toss up to me on fuse versus auto-resetting circuit breaker. If the circuit breaker is tripping and then trying to reset you will not know about it and arrive with dead battery. This is true with a fuse as well. Only way to tell is to install a lamp on the camper side of the circuit breaker/fuse.
  • ScottG's avatar
    ScottG
    Nomad
    Aug 20, 2014
    I would use an auto-resetting breaker instead of a fuse.
    As far as the starter pulling current out of your TC batteries, it won't have much effect because there's ample current available from the trucks batteries and even if they were low, that 8 awg wire is going to perform as a current limiter.
    I ran the same setup with my Ram and a TC and never had any problems.

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