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rbpru's avatar
rbpru
Explorer II
Jul 21, 2017

Battery boomdocking dlemma.

We have been considering doing a bit of boon docking. We have noticed several opportunities in our travels.

Unfortunately we barely get two days use out of our battery even though we have installed LED lights, and the frig, water heater, run on propane. The furnace is a big draw so we seldom use it, that leaves only the pump and phantom loads. I even shut off the TV booster and pulled the fuse for the radio/DVD player.

According to the battery information I have gathered, my 100 A/hr. battery would like to be charged at C/10 or 10amps for 10 hours.

So, I have three questions.

1. If the battery is half depleted, does it only take 5 hrs. at 10 amps?
2. If I park in the sun with solar panels on the roof, the TT heats up like an oven. If I park in the shade the solar panel lose their output; unless I move the panels off the TT roof to the ground. But, then I must leave them unattended while we tour the local tourist traps. What am I missing here?
3. I could buy a small generator to provide the 10 amp charge but then I would have to leave it running unattended for 10 hours when I am not there or run it at night when we are in camp. These sound like poor ideas.

At this point I am curious what others do to keep their battery charged up.

37 Replies

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  • ktmrfs's avatar
    ktmrfs
    Explorer II
    Jul 21, 2017
    yes, the ideal charging current is around C/10. but with a flooded cell lead acid you can exceed that by a great deal without any issues.

    First thing is to get a charger that can actually charge at a high rate. If you have a WFCO charger, common on many trailers the short answer is it won't. not even close. get a PD or iota 60A or so charger.

    yes, 60A is well over C/10, but it won't hurt them a bit for the number of cycles you will use them for when dry camping.

    I have often charged a bank of 2 GC, 250AH at 60A, C/4 and occasionally at over 100A C/2 at the start no issues.

    next, stop charging when the batteries are around 80 -85 percent charged. or rely on solar to top off. by that point charging current is very low, and it will take longer to get to 100 percent than it took to get from 50 percent to 80 percent.
    as for solar, we have portable panels. leave them in the sun day and night. yes, they could grow legs, but in 10 years haven't had any issues. That way the trailer is in the shade, panels in the sun. best of both worlds.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jul 21, 2017
    I camp in the sun and use 2 Honda generators to run air.
  • wildtoad's avatar
    wildtoad
    Explorer II
    Jul 21, 2017
    If you're going to boondock you might think about more batteries then do what others suggest regarding recharging.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Jul 21, 2017
    Increase the size of the battery bank as much as is possible.

    Battery charging is not linear. It slows down as the battery bank gets closer to full.
  • gmw_photos's avatar
    gmw_photos
    Explorer
    Jul 21, 2017
    I think you are going to find the real answer is: "it depends".

    The most important comment I have seen from folks who do a lot of off grid camping is, put as much solar on your roof as you can stomach to spend. And don't cheap out. Get the best batteries, solar panels and charge controller you can. It ain't gonna be cheap. I saw one guy had spent $16K on a big setup, although that is the extreme end of it from what I have researched.
  • mbopp's avatar
    mbopp
    Explorer
    Jul 21, 2017
    I disconnect the factory WFCO converter and use a deck-mount IOTA-55 w/ charge controller to charge off a generator. Since it's a smart controller I get away with an hour a day of generator time & could probably go 1/2 hour a day. I'm running dual G27 12V batteries.

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