Switching between seperate battery banks?

System
System Posts: 2,511 admin
in Solar Beginners Corner #1
Does anyone know how I could, (or if I should), incorporate some kind of switch so that my 135 watt PV panel/charge controller can charge 2 separate 12V 1100AH battery banks?

anybody know a brand/kind of switch that would work for this?

And then, if its possible, a switch between the battery banks and the inverter?

Or is this a bad idea?:blush:
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  • tallgirl
    tallgirl Solar Expert Posts: 413 ✭✭
    #2
    Re: Switching between seperate battery banks?
    goodhustle wrote: »
    Does anyone know how I could, (or if I should), incorporate some kind of switch so that my 135 watt PV panel/charge controller can charge 2 separate 12V 1100AH battery banks?

    anybody know a brand/kind of switch that would work for this?

    And then, if its possible, a switch between the battery banks and the inverter?

    Or is this a bad idea?:blush:

    Can you even charge 1 of those banks properly? 135 watts @ 12VDC is about 11 amps. 1100AH / 11 amps is a 100 hour charge rate.

    You can do it, but then you'd be at an even lower rate of charge -- 200 hours.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #3
    Re: Switching between seperate battery banks?

    For a switch--this one should meet your needs. One for the charger selection, a second for inverter selection.

    wind-sun_2069_19350882

    Power wise--Tall Girl is correct that you have way to much battery bank for the amount of solar array you have.

    You may not even have enough to just trickle charge your two banks.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #4
    Re: Switching between seperate battery banks?

    This http://www.smartgauge.co.uk/smartbank.html might also work. (I have no experience with it, just found it on dem intawebs)
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  • tallgirl
    tallgirl Solar Expert Posts: 413 ✭✭
    #5
    Re: Switching between seperate battery banks?
    BB. wrote: »
    For a switch--this one should meet your needs. One for the charger selection, a second for inverter selection.

    wind-sun_2069_19350882

    Power wise--Tall Girl is correct that you have way to much battery bank for the amount of solar array you have.

    You may not even have enough to just trickle charge your two banks.

    -Bill

    Thanks for the pointer to that switch. I'm looking at some electrical cleverness for battery-backed grid tied systems and might just have to use that.

    As regards trickle charging the batteries, they MIGHT be able to be kept charged once they are fully charged, but after that, forget it.

    I use a 25A battery charger to perform the initial charge on 48V banks I assemble. These are 215AH @ 48V banks, wired as 860AH @ 12 volts to perform an initial charge. The charger lowers to well below the 135 watts of the OP. But that's after many, many hours well above 135 watts.
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