6.4KW pv System 90% installed-question

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Gitchee Gumee Kid
Gitchee Gumee Kid Registered Users Posts: 19 ✭
in Solar Beginners Corner #1
My 6.4KW pv system is about 90% installed.
Components:

30 Kyocera 215W panels ( two pole mount )
Xantrex XW6048 Inverter
Xantrex MPPT 60 ( two )
Sm battery bank -->four 200AH AGM's
8KW diesel generator 120/240 vac

Location NW Wisconsin

Question-->At a 25 % max depletion of the batteries could I power let's say a freezer thru the night?

I'm seriously thinking of going the extra mile and get 8 more batteries.

TIA

GGK
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #2
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    Re: 6.4KW pv System 90% installed-question

    What is your daily load (Watt*Hours per day)?

    We usually suggest people not get too many batteries unless they have a specific need (for example, fuel is hideously expensive and/or difficult to get to the site).

    Even then, when adding "more batteries"--frequently more solar panels are needed to really recharge the bank well...

    Then there is the whole cost of replacement 5-8 years or so down the line (or, heaven forbid, somebody takes out the entire battery bank a year later when some heavy loads where left on during winter).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
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    Re: 6.4KW pv System 90% installed-question

    Let's see ... 200 Amp hours @ 25% DOD is 50 Amp hours. Times 48 Volts nominally is roughly 2400 Watt hours. Or about what I use to run the whole cabin daily, including refrigerator.

    That much panel would support 800 Amp hours or so of battery.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #4
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    Re: 6.4KW pv System 90% installed-question

    Also, what is your peak load/surge load?

    If that is a 200ah 48 volt battery bank, that would support about 2,000 watts peak and 4kW surge loads.

    With a 6kW array, you should have a minimum 600ah 48 volt battery bank--otherwise you are probably going to have over voltage issues at the battery bank (I think is a F49 inverter fault)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #5
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    Re: 6.4KW pv System 90% installed-question

    the simple answer is yes it could power it over night and will drop the battery capacity further even though it most likely would not exceed the 50% dod point.

    i would recommend 4 more batteries for as it is you are pumping quite a bit of power into those present 4 batteries at around 100a give or take. if they are concordes they can take it, but i would not be comfortable with that arrangement. any large total loads to the inverter may also bog down the batteries so that aspect has to be kept in mind too.
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