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Tiggs's avatar
Tiggs
Explorer
May 21, 2013

Adding a second battery?

My new to me TT has a 12V Interstate deep cycle marine/rv battery, spm-24. Looked on line and it offers 140 min. at 25A and it looks like I'm could use as much as 10 amps an hour without the furnace when dry camping, which is what I mostly do. This is probably why my battery is dead in the morning so I want to add a second battery. I would like to add a bigger battery, offering more amp hours but not sure if I have to pair the battery with a similar sized one or if I should replace this battery and convert to a 6V system.

I would like to get to the point where I have enough power at night to run my frig, a light or two, the furnace and the TV for a few hours. Many folks seem to be happier with their 6V power set up over the 12V, but not sure exactly why this is so.

Wonder if I shouldn't go to a 6 Volt system for the general house service and isolate the 12V battery, put it on an inverter and use it only for the TV, thinking if I over did the TV use, I wouldn't compromise my power for the "necessities".

Thoughts?

Carolyn

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  • EsoxLucius's avatar
    EsoxLucius
    Explorer
    May 21, 2013
    You won't convert to a 6 volt system although you can convert to 6 volt batteries. Two 6 volt batteries in series provide 12 volts at the same AmpHour rating as one of the batteries. Two 12 volt batteries in parallel provide 12 volts at double the AmpHour rating of one battery. Four 6 volt batteries in series/parallel provide 12 volts at double the AmpHour rating of one battery. Your TT operates at 12 volts. If you have abused your existing 12 volt battery (the word "dead" indicates abuse) you will have to replace it if you want to add an additional battery, even if it was the same as the one you have now. How much room do you have for batteries? Is that area isolated from the TT interior and vented to the outside?

    I would see how much room you have and get a pair of the biggest 6 volt true deep cycle batteries you can find and fit. 220 AH (two 6 volt batteries) should be enough for your described usage, although what do you have or plan for a charging regimen? Four batteries would give you more than enough power for the use you describe.

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