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mclaned1's avatar
mclaned1
Explorer
Apr 23, 2015

Battery size question

I think I have decided to change over to a 6v system.I currently have a single 12v group 24. Most likely going to get them from Costco.
My questions are
What size 6v is close to the same size(I don't have a lot of space between the trailer MD the propane tanks)
Will my WFCO 35amp power converter work with the new battery system.
Do I need an additional battery charger when its sitting in my driveway (its always connected to shore power when sitting at home)
Trailer is a 2005 prowler 24bh

Thanks
  • If you check the Trojan site, you can probably find the measurements of the T-105 Golf cart batteries or google "gc2 battery size (or measurements)" You will wire them in series to produce 12 volts so the charger won't care.
    If you want to upgrade your controller, this is what I used and changes it from 3 stage to 4 stage plus more modern output.
    WFCO upgrade to PM Boondocker
  • What size 6v is close to the same size(I don't have a lot of space between the trailer MD the propane tanks)
    You should contact Costco & get exact dimensions of the 6-volts you want.

    Will my WFCO 35amp power converter work with the new battery system.Yes, It will work.

    Do I need an additional battery charger when its sitting in my driveway (its always connected to shore power when sitting at home)No, you do not, but you should verify the exact model of the converter & it's charging profile & maintain water levels in the new batteries.

    READ THIS
  • Just to be clear, you aren't really changing to a 6V system. You're replacing your existing 12V battery with a different 12V battery that is made up of two separate sections in series (each of which is nominally 6V).

    This means, of course, that you need to have two 6V batteries. If you don't have space for two batteries, you can't use the 6V batteries, and need to find a 12V battery instead. From the pictures I can find, I assume you're constrained mainly by the width of the batteries but not so much by their length and could readily fit the two 6V batteries end-to-end across the tongue A frame.
  • Converter specs
    model WF-8835
    Input 105-130VAC, 60hz, 600watts
    Output 13.6VDC, 35amps

    Battery area
    23 1/2 wide
    8" wide
    Because of the angle of the trailer the max height is 9".
  • My Costco GC batteries had the same footprint as a Group 24 but were a little taller. I eventually replaced my battery boxes with 6V ones. If height is an issue with the 12V you have, the 6V batteries might not fit.
    6V battery boxes from Amazon
    A response to a question for these items says that the boxes are "Measurements are approximate as the boxes are on the trailer. With top on 12 1/2" high x 10' wide (top) x 14 1/2 " long, Bottom of box is 7 1/2' x 10 3/4""

    As DrewE pointed out, you'll need 2x6V batteries. 2 batteries are a tight squeeze for the tray on my TT tongue, but they do fit.
  • Hi,

    The wfco is known to have a problem going to boost mode.

    This is what is balanced and best for twin twelve volt batteries. Unless you wire this way the battery bank combined with a rather poor converter will lead to early failure.

    My 12 volt jars are over nine years old and starting to show their age.



    As it often doesn't cost a dime more to do this, I think it is worth the trouble.

    If you wish to understand the "why" surf here:

    correctly interconnecting multiple twelve volt batteries

    Others may say it doesn't matter--but unless there is a compelling reason to not optimize charging and discharging why not do it the best possible way?

    Here is a video of 3 twelve volt batteries that have been wired in an unbalanced manner for 2 years. They have been equalized. The test shows how CCA has been adversely affected.

    unbalanced for 2 years
  • Two six volt batteries connected in series equals one big 12 volt battery. In general six volt batteries are taller than type 24 batteries - may not be an issue if the batteries is located outside.
  • mclaned1 wrote:
    Will my WFCO 35amp power converter work with the new battery system.
    Do I need an additional battery charger when its sitting in my driveway (its always connected to shore power when sitting at home)
    Trailer is a 2005 prowler 24bh

    Thanks
    Maybe

    Big issue with WFCO is not switching modes when expected. Many just charge at 13.6 volts. This would be a slow charge resulting in extended generator run time and possibly chronic undercharging.

    So monitor the 35a WFCO voltage to see you are getting what you expect. Low battery starting at 12.1 volts or less should kick the converter into boost and you will see voltage steadily climb to 14.4 volts and hold for close to four hours. Then 13.6 normal mode for a few days before it drops to 13.2 volts for storage.

    No other float maintenance is needed if your WFCO actually works.

    Please post for recommended replacements if your WFCO is doing something else.
  • One item my dealers head mechanic recommended. If you are going to use the on board system for charging, because of the greater capacity (whether 2 6v or a really big 12 v) the installed wiring/fuse systems may not be able to handle the initial current sent to charge deeply discharged batteries. A fuse will blow. They recommended to replace the charge line fuse with a self resetting circuit breaker. It may be a little slower to get everything up to 100%, but you don't have to replace the wiring, etc. to accommodate the additional current.

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