MIxing AGM/FLA in the same RV

icarus
icarus Solar Expert Posts: 5,436 ✭✭✭✭
in General Solar Power Topics #1
Quick question about AGM's

What are the consequences of using AGMS for house batteries, coupled to a RV with a FLA, and using traditional alternator as a charge source?

Tony
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: MIxing AGM/FLA in the same RV

    the mixing of the 2 types is not recommended unless one may need to give a small boost in the charge levels of one of them temporarily. it is probable that neither may reach a full charge and each have differing voltage characteristics and not just for charging.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #3
    Re: MIxing AGM/FLA in the same RV

    If you're not drawing from both for loads it is not that bad.

    I have some AGM I got for free on a UPS change out that I parallelled with my stock of flooded cells. During discharge there is about as much variation between the AGM and flooded as there is between series strings in parallel of the flooded. Things tend to even out over the discharge cycle.

    During charging the same thing happens. During phase one there may be more current initially pushed to AGM but later the flooded take more of the current. Once they reach float or absorb you are on voltage regulation so each string is independent.

    If you repeat shallow cycle, the AGM's will carry most of the work.
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  • dmiller
    dmiller Solar Expert Posts: 68 ✭✭✭✭
    #4
    Re: MIxing AGM/FLA in the same RV

    Your really not talking about one bank. Do you have a separator or an isolator between batteries? Generally these would not be simply connected with a cable.
    The issue with the alternator is getting enough but not to much voltage on the AGMs.
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #5
    Re: MIxing AGM/FLA in the same RV

    Reminds me of a problem that I have been wrestling with but have tabled for the time being.

    My camper was delivered with a Group 24 FLA mounted on the tongue of the trailer. It is charged by the tow vehicle's alternator. It is uninstalled at this time. I don't know the wire gauge that is used from the alternator (HD 100A) to the 7 pin trailer connector. I had the "kids" at U-Haul install the hitch (and proportional electric brake controller) and I cannot guess where they drew the 12V line to the trailer from. I can't imagine that they installed #8 from the engine to the tailgate.

    So, no battery in the trailer will get anything close to charging volts (due to cable voltage drops) nor will the 3-way fridge get enough power to cool much at all.

    The AGM house batteries are charged (in my persistently parked mode) by solar or genny.

    When I take this issue off the table I'll post anew.

    Enjoy!

    K
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #6
    Re: MIxing AGM/FLA in the same RV

    Thanks one and all.

    I am doing some work on an RV for some folks, and have been reading a number of forums, and it is amazing how ignorant of basic battery stuff Rv'ers tend to be!

    Tony
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  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    #7
    Re: MIxing AGM/FLA in the same RV

    YEAH! Tell me about it!

    I mean don't.

    K
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #8
    Re: MIxing AGM/FLA in the same RV
    icarus wrote: »
    Quick question about AGM's

    What are the consequences of using AGMS for house batteries, coupled to a RV with a FLA, and using traditional alternator as a charge source?

    Tony

    Shouldn't be any big problem. I guess it would depend on what the voltage regulator is set to and what the FLA and AGMs like for optimum voltage.

    It won't be a perfectly optimum setup, but will probably be "close enough"




    Well, while researching this, I ran into what looks like a direct ripoff of the NAWS battery FAQ:

    http://www.solarnavigator.net/battery_charging.htm
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