Do I care about rate of charge..if.

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Uncle Dave
Uncle Dave Registered Users Posts: 24 ✭
in Off Grid Solar & Battery Systems #1
All I'm using solar for is a strategy to reduce my current depth of discharge - not fully charge my bank?

Another 7-10% reduction in my daily DOD will mean a lot over 7-10 years of commercial use.

My system gets fully charged every night regardless of what I get from solar so that isn't a concern.

Thanks guys.

Uncle Dave
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Do I care about rate of charge..if.

    If the batteries are receiving their charge from a source other than the solar it does not matter how much solar contributes.

    There are many RV installs where there is not enough PV to do full charge from solar so it just slows down the rate of discharge. As long as they do get charged properly and in time, that's all the batteries care about.
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  • Uncle Dave
    Uncle Dave Registered Users Posts: 24 ✭
    #3
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    Re: Do I care about rate of charge..if.
    Cariboocoot wrote: »
    If the batteries are receiving their charge from a source other than the solar it does not matter how much solar contributes.

    There are many RV installs where there is not enough PV to do full charge from solar so it just slows down the rate of discharge. As long as they do get charged properly and in time, that's all the batteries care about.



    This is a work van scenario and Im looking to coddle my expensive bank with a shot in the arm from the sky.

    I have an onboard genset and and plug in every night, but do as much work off the inverter as I can get away with.

    The system gets regular charging from the genset in 20-30 minute chunks 5-6 times a day and when driving , or when the air conditioner is running

    This will help me out most in the winter when Im not running the genset much.

    Thanks!

    Uncle Dave
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #4
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    Re: Do I care about rate of charge..if.

    Sounds like a good plan, and opportunity charging will help keep the overall daily DOD down.

    I'd just be careful not to go too far with it. You want the batteries to get *some* exercise, ie at least about 10 - 15% DOD, otherwise there is a tendency for the natural formation of sulfate to clump, and not spread evenly during discharge. And for stationary flooded batts, you want enough charging to take place to help avoid stratification.

    In other words, without enough of a discharge, you can end up in a no-mans land between a cyclic and float application, and may be subjecting your bank to more time spent in absorb than necessary. One also wants to weigh the cost of fuel, poco power etc vs keeping a bank topped up - I'd aim for at least 10% DOD each cycle.

    Sounds like you are on top of it already.
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  • Uncle Dave
    Uncle Dave Registered Users Posts: 24 ✭
    #5
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    Re: Do I care about rate of charge..if.
    PNjunction wrote: »
    Sounds like a good plan, and opportunity charging will help keep the overall daily DOD down.
    I'd just be careful not to go too far with it.
    You want the batteries to get *some* exercise, ie at least about 10 - 15% DOD
    Sounds like you are on top of it already.

    Im still expecting between 30 to 40% DOD daily. Its going to keep getting a workout.

    Id just like to keep from going to 50.

    Based on my battery specs that little bit of daily amperage should buy me an extra 500 to 1000 cycles. It could add another year or more of life to my bank.

    Over ten years which is the expected lifespan of the vehicle - spending a little now will ultimately mean a lot of savings as batteries will likely continue to rise in cost.

    Uncle Dave
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