Rv Batteries

Unless I missed an RV section, I'm posting this question here......:)

My Motorhome now has two sears deep cycle 12 volt batteries that are not yet a year old. They don't seem to hold up well at all. After dealing with some of the
"greatest" on this site concerning my home solar issues, this came to my mind.(and believe me this does not happen very often). What if I were to get rid of the two "low amp" sears deep cycles and switch to a pair of series wired 6volt t105 Trojans? :confused:


  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Rv Batteries


    The problem you’re seeing is common in RVs. It might be a problem with the batteries themselves, but it could be a problem with the RV’s electrical system. Specifically, the alternator and regulator may not be supplying the correct voltage and/or enough current to properly charge the batteries. If this latter issue is a/the problem, then new batteries probably won’t help.

    It would be worth checking the RV’s charging voltage by measuring the voltage at the house battery terminals. If it’s below 14.4 V, then that’ll be a problem for just about any battery except for VRLA gel types. If it’s ~14.4 V, then it’s OK for “deep-cycle” batteries like those from Sears, Interstate, or Wally World. But, those great T-105 batteries need 14.8 V, and all of these flooded-cell batteries require periodic equalization at ~15.5 V.

    One solution might be to figure out what batteries you want, and then charge them from a good three- or four stage charger (plug-in or solar) while you’re at home.

    A series pair (12 V nominal) of Trojan T-105 batteries would work well if regularly charged from something like the Xantrex TC-20+ set for cold flooded-cell batteries.

    See: http://www.xantrex.com/web/id/69/p/240/pt/7/product.asp
    and: http://store.solar-electric.com/tc-20-.html
    and: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance/ChargerSelection.aspx
    and: http://www.trojanbattery.com/Tech-Support/BatteryMaintenance/Charging.aspx

    Jim / crewzer
  • backroadbackroad Solar Expert Posts: 185 ✭✭
    Re: Rv Batteries

    Crewzer, it's like you're my own personal solar/battery guru. I ask and you answer...thanx again.

    I will get out and check the Coach voltage.

    I do have an awesome leftover (from my 24volt solar battery swap) that probably might, could be too much. It's an Iota 12 volt 90 amp charger. If'n I were to upgrade to 4 of the t105's, could it be used or is it way too much.:cry:
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Rv Batteries


    Following Trojan's guidelines of charge current equaling 10% to 13% of battery capacity, and appropriate charge current for four T-105's configured as a 12 V x ~450 Ah bank would be 45A to 58 A. Accordingly, I think the 90 A charge would be too big.

    Always glad to help where I can!
    Jim / crewzer
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