Mod: adding a second battery in parallel on the tongue

Discussion in 'My Favorite Mods, Tips, Tricks (and Blunders!)' started by PopUpLarge, Jul 11, 2018.

  1. PopUpLarge

    PopUpLarge New Member

    Jul 10, 2018
    I want to run two batteries in parallel on my new camper but I'm currently a little short on tongue space. Currently the spot for the battery is on the passenger side tongue arm. Since the two deep cycle batteries I have run about 60 LBs each, is it important to balance both sides of the tongue? I can re-arrange things to make this happen (previous owner moved spare to the tongue and also replaced the original roller jack with a bolt-on one). Or can I get away with centering the second battery in front where the stock jack used to be?

    Why do I have two deep cycle batteries? I was talking to a guy I know about how excited I was to get my first camper, and how I needed to find a good deep cycle or marine battery. He said, "Well, the place I work gives us deep cycle batteries for free because they rotate them out of their Universal Power Supply applications after a year or so. Have two I have laying around."

    So I got two batteries for nothing.
  2. PopUpLarge

    PopUpLarge New Member

    Jul 10, 2018
    Also, here's your opportunity to tell me why running two LP cans is better than two batteries.
  3. Wrenchgear

    Wrenchgear Near Elmira, Southern Ontario

    Aug 5, 2010
    5 Star Eagle Camper
    Because you can't run heaters off of batteries. If you're camping in cold/damp weather, you'll want that extra propane to run your furnace all night long for 2 weeks.
    If running your fridge on batteries, the batts be dead in no time. Run that fridge on propane and it will cool quicker, get colder, and run forever on that propane.
    emoney, kitphantom and nineoaks2004 like this.
  4. nineoaks2004

    nineoaks2004 Every meal is a picnic and every Day is a holiday

    Oct 15, 2006
    Graceville, Florida
    adding another 60 lbs to the tongue might cause a problem with the hitch weight
    which should be 10-15% . You may have to add weight to the rear to compensate
  5. giadiep

    giadiep Active Member

    Sep 5, 2015
    Syracuse, NY
    Your single battery will die in 2 days running the furnace blower motor. A single propane tank will outlast a single battery unless you have a way to recharge. If tongue weight or space is a concern, then just carry the extra battery in the pup and swap when needed.
  6. neighbormike

    neighbormike Well-Known Member

    Oct 6, 2012
    On my pup I had only enough room for one battery and one lp tank.... so I installed a 30lb tank and group 31 battery. I could consistently go 3-4 nights with heat (with conservative useage obviously).
  7. kitphantom

    kitphantom Well-Known Member

    Dec 26, 2009
    Albuquerque, NM
    A photo of the a-frame might help, so we can see the space that you're dealing with. Do consider tongue weight. Are the new batteries 12v or 6v? 6v deep cycle batteries are taller than 12 v, so that is a consideration too, in some cases. [We went to dual 6v golf car batteries on our small TT, and my husband had to get creative, since the cure of the front wall made it impossible to use the double battery box we found.]

    For the other comments - when we finally got a pup with a battery, we made sure to have a way to recharge the battery by the first full season. In our case, solar works well. On the one trip we took before we had solar, when we knew it would be chilly, we got a site with power. (Since the lows hit the teens F, and the highs were in the 30s, for a week, that was a good thing.)
    We had two LP tanks on that pup, so that we didn't have to worry about running out of heat on longer, colder trips - we also added an auto-changeover, so there's no need to change connections from one tank to the other. (I'm convinced the tanks are going to run out in the middle of a cold, stormy night - on the pup the issue would also have been trying to change connections while crouched under the bunk.)
  8. GrueMaster

    GrueMaster Active Member

    May 22, 2013
    Saint Helens, Oregon
    On my pup I have 2 tanks and 1 battery. Tanks will last over a week heating the trailer, and the battery can survive the night with heat and CPAP. For recharging, I have a 100w solar array from Harbor Freight (I know, quality etc). But this set does a decent job recharging the battery. Worst case, I spin the truck around and hook up jumper cables to the tongue battery and run the truck for a little while to recharge it.
    BillyMc likes this.
  9. leningradka

    leningradka Spending a small fortune to live like homeless guy

    Apr 26, 2016
    Phoenix AZ
    GrueMaster, how can you run CPAP off battery?
  10. jmkay1

    jmkay1 2004 Fleetwood/Coleman Utah

    Oct 10, 2013
    Northern Virginia
    Everyone's style of camping is different. If you find you camp with hook up's 90% of the time than the second propane tank will be more useful than the second battery. If you dry camp (camp with no hook ups) then the battery bank will be more Benificial. in the summer you probably won't even break into the second propane tank because it's the furnace that is the propane hog. So you can probably get away with only one propane tank until it starts getting cold. If your camping with hookups more often than not one battery is more than sufficient. Currently I have two propane tanks and only one battery. I do dry camp occasionally And even when using the furnace in the 50s then I can make 3 nights with conservation efforts on my group 24 battery. If I didn't need my furnace, with conservation efforts I may be able to make it 5 nights. That means LED lights, water pump once a day for dishes, turning everything off when not needed etc. phone is charged in the car or a separate battery bank I have for it. if I camp longer off grid I may consider adding a second battery or get a group 31. So best to really look at how you camp more before going through all the trouble.
  11. xvz12

    xvz12 Well-Known Member

    Apr 6, 2017
    New Plymouth, ID
    My pup originally came set up for two propane tanks, with a single battery centered just in front of them. I found the rails that the tanks sat on were just the right width for battery boxes, so I mounted 2 batteries side by side on the rails originally meant for the propane bottles, & went to a single bottle in the front where the battery originally sat. We very rarely use the furnace, & the bulk of our cooking is done outside on a Coleman 3-burner stove, or on a Blackstone griddle, so a single propane bottle generally lasts us all summer. I have two Renogy 100 watt panels mounted on the roof in tilting mounts, & they've done a good job of keeping our batteries topped off.
  12. kitphantom

    kitphantom Well-Known Member

    Dec 26, 2009
    Albuquerque, NM
  13. GrueMaster

    GrueMaster Active Member

    May 22, 2013
    Saint Helens, Oregon
    I have wired 12v accessory sockets (car cigarette lighter jacks) into my pup and bought a 12v adapter for my CPAP on Amazon. It doesn't take much to figure out the draw for a 12v 6amp (max) unit, and then getting battery power suitable for that load. I also decreased the load of other components (switched to LED lighting, run fridge on propane only, etc), so that during the day the solar panels will recharge the battery easily (they were putting out ~14.4v last weekend sitting on the roof of my pup all day).
    leningradka likes this.
  14. roybraddy

    roybraddy Well-Known Member

    Mar 23, 2016
    King George, Virginia
    My batteries are mounted on a rail that runs across the top of the tongue area. I have had four batteries installed lined up end to end across my trailer tongue.... It has a small right angle metal welded to the the tongue area. This has two Propane Tanks in front of that and the trailer jack in front of that. The batteries are next the trailer box (or front deck in my case)

    Roy's image

    When I was using four batteries end to end I installed a second right angle strip inside the one welded to the frame as shown. Using four batteries they extended our over the tongues a few inches on both side...

    If you can get angle strips welded across the tongue then you can add several different ideas you may come up with for holding your batteries...


    Maybe a TOOLBOX from auto store with lid like this...

    Or do what i am going to do for my new upgraded battery bank using a TORKLIFT BOX A7710RS with a slide off lid with a couple of 10WATT solar panels on it to keep the batteries topped off during high sun days...

    Since i will have two groups of batteries installed I want a second 10WATT Solar panel on the opposite end... One for each battery group. I will be using two groups of 6VDC batteries in series and will be able to add them together with a BLUE SEA high current switch...


    My upcoming new Batteries Plans at any rate...

    Roy Ken
    Garrity likes this.

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