[email protected] Dual Battery Conversion

lightningdonlightningdon Member Posts: 119 ✭✭✭
edited June 2017 in Conversions & Upgrades
So I converted my rig from the single 12 v battery to a dual 6V battery set-up. As I posted earlier, I picked up 2 Duracell 230AH batteries from Batteries and Bulbs for $98 each. I do not have time to do a more permanent solution as I have a run scheduled in just a couple weeks. This conversion is quick and easy, maybe 1 hour.
First photo shows the stock [email protected] tub once battery and 20lb propane tank are removed. Notice there is a spot for a battery under the tank mount. Next I used a grinder to cut loose the tank bracket.

Here you see the tank bracket removed. Touched up the cuts with paint to prevent rust.

Here both batteries are set in place and wiring done. Yea, I will restrap the right side battery. I drilled 4 holes in the bottom of each battery box. I did not use the lids as the boxes sit too far to the rear and the lids hit the camper.

Here is the propane tank adapter installed. This will allow me to use 1lb throwaway canisters rather than the 20lb tank.

Here you can see the 1lb tank installed and sitting pretty between the batteries. Oh...the battery slot on the left was a little larger than the one on the right so I just used a piece of 3/4" pine to hold the battery box to the outside to clear the gas pressure regulator.

I may eventually reconfigure to allow placement of a slim 5lb tank. Will probably need to move the batteries outboard and rearward a bit. The slim 5lb tank is 9" diameter, so will be a tight fit. May even need to eliminate the battery boxes.


  • Michigan_MikeMichigan_Mike Member Posts: 8,776 ✭✭✭✭✭
    edited June 2017
    Good looking set-up and obviously a huge boost in your power to the trailer!  I love my 6V batteries as they nearly triple my capacity and I am able to keep things topped off with my 200W Zamp portable charge system.  

    In looking at your photos however I am wondering whether or not the batteries could be re-positioned inside the tub differently to gain more room and allow for a larger propane tank to be added in with them?  I know that you have your brackets welded securely in place to accommodate both batteries, but if you made a template of the tub, cut lets say a piece of treated lumber to (be dropped down into the tub area) utilize all surface areas between the front of the trailer, the side tub areas and fit it inside the tub and be bolted it down, whether or not you'd gain additional placement area for both batteries and a larger propane tank?  If the batteries could be placed end to end lets say or even in an "L" configuration the additional space gained might be just enough to allow the 20# tank (or even a 10# tank) to be set in with the batteries?  I also am aware that the tongue weight changes here, but believe you could figure it out and adjust the cargo weight accordingly to allow for the added weight.  

    It's just a thought and would allow you to gain and use all space within the tub and allow a larger propane tank to be added in.  
  • lightningdonlightningdon Member Posts: 119 ✭✭✭
    I plan to do just that. I needed a quick and dirty solution for my Independence Day trip. After I return from that trip, I will be digging in to a more permanent solution. I don't really need the capacity or weight with the 20 lb cylinder but would like a 5 lb tank. Thanks for your feedback. I wanted everyone to see this process as no one seems to have any in process pictures just the finished shot.
  • gadgetzzgadgetzz Member Posts: 160
    as I recall my stock battery holder only allowed for one battery unlike yours. I was able to to lay my two batteries parallel to the body and still squeeze in my stock propane tank but it was very tight so I opted for new tongue box. If at the time I thought I could get by with 1lb propane bottles I would have done what you did.
  • Gypsy222Gypsy222 Member Posts: 101 ✭✭

    lightningdon, a big thanks for posting as I have the same battery tray(s) in my tub.

    I'm still getting by on my original battery  with the help of my 80 Watt Zamp. When the stock interstate starts to get too weak, I will need to commit to what type of upgrade, this setup (2-6volts) or a larger group 27.

    Thanks again for posting, very helpful.

  • iamlucasiamlucas Member Posts: 1
    I have a 2016 [email protected], and the long side of the welded battery frame on my unit is 11".
    I looked at an interstate SRM-27, and it's dimensions are: SRM-27: 12 3⁄4 x 6 3⁄4 x 9 1⁄2
    (from http://www.interstatebatteries.com/m/category/rv/rv-deep-cycle )
    So, it's not going to fit without modification.

    However, the SRM-24 dimensions are the same as the stock HD24-DP that came in my unit, but 40% larger runtime.
    I don't feel that is sufficient battery reserve. Even the single SRM-27 would only be a 60% increase in Amp hours. 

    My dilemma is as follows:
    Even with 2x6V setup, you are only looking at 3 summer days with the norcold NRF-30.
    (I just rewired my NRF-30 with 10 gauge wire direct to the inverter, and am able to get about 24 hours on a fully charged HD24-DP. (I'm about to redo my test with a battery monitor to get actual consumption details vs temperature)

    3 days (with the dual 6V system) is sufficient for a weekend event, but not anything longer.
    That means doing one of three things: generator, solar, charging via tow vehicle.

    I am just ordered a Renogy 100 watt suitcase kit. From reading and watching reviews, it seems this kit will easily provide 550 watt hours per day. (Longer for summer days here in the northwest). I don't think that would be sufficient to fully recharge the battery every day, but I think it would be enough to extend battery life on the stock battery. The question is how much additional time would it gain? The norcold nrf-30 draws 50 watts. 550 watts from solar would be 11 hours of full time reefer usage, 22 hours if it it was using a 50% duty cycle.

    It is likely the reefer will require the most energy when it is the sunniest, so my expectation is that solar would fully satisfy the reefer requirements during the day, while adding some small surplus to the battery for charging. The reefer would rely on battery at all times when there is no solar, so eventually the battery would deplete. Any guesses to how long that would take? (assuming the refer was the only significant source of battery usage)

    My thinking is that investing the money in the solar kit is more effective than modifications and new batteries. Realistically, I really want both solar and dual 6V, but I'm going to wait to mod until I test the solar kit with existing battery. :)

  • Michigan_MikeMichigan_Mike Member Posts: 8,776 ✭✭✭✭✭
    You might also experiment with power consumption by unplugging the Norcold at bedtime, firing it back up in the AM as I do this with my ARB in an effort to eliminate battery drain and conserving energy.  Unless it is boiling hot at night you will find out that this works and if the unit is sealed up and unopened you will only see a few degree drop in temperature too.  My 200 watt Zamp panel tops off my two 6-volt batteries in optimum sunlight and via conserving energy I can run off grid for quite a while.  It does take an acute awareness, vigilance and practice!  
  • lightningdonlightningdon Member Posts: 119 ✭✭✭
    I have been able to do 5 days, full time fridge, occasional lights and a couple movies and pull out at 12.1 volts. That was with moderate temps, not blazing hot days. With my original 12V battery it was a struggle on simple weekend trips. Now those weekend trips I can run everything and not be concerned at all about my power needs.
  • stargazer7467stargazer7467 Member Posts: 269 ✭✭✭
    Would i be too much of a bother asking for measured tongue weight? Id like to do this to my shadow.
  • stargazer7467stargazer7467 Member Posts: 269 ✭✭✭
    i went to work and weighed them. Theyre about 70lbs each.
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