Maximum battery charging current

Nabiru3
Nabiru3 Registered Users Posts: 13 ✭✭
in Off Grid Solar & Battery Systems #1
so I have 2 flooded lead acid (153Ah each) batteries (which their datasheet states that the maximum charging current is 13% of C20) both connected in series, meaning in my case I should charge the batteries with a current less than 19A. But I have solar panels producing around 27A per hour. Does this mean the solar charging will damage the battery's health ? and can/should I limit the charging current of my solar panels ?.

Arigatou everyone 😊.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    Nabiru3 said:
    so I have 2 flooded lead acid (153Ah each) batteries (which their datasheet states that the maximum charging current is 13% of C20) both connected in series, meaning in my case I should charge the batteries with a current less than 19A. But I have solar panels producing around 27A per hour. Does this mean the solar charging will damage the battery's health ? and can/should I limit the charging current of my solar panels ?.

    Arigatou everyone 😊.
    Likely not enough information. 

    You have 2 batteries in a 24 volt configuration for a battery bank of 24 volts at 153 amps?

    What are your solar panels? and type of charge controller? And how are you determining the 27 amps?

    An MPPT type charge controller can often limit the amount of output. 
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    edited July 2018 #3
    And what is the array configuration (series/parallel connections of the panels)?

    Also, just a quick note... Amps per hour---It is just Amps.

    Amps is a "rate" already.  One coulomb of charge going past a given point per second.

    1 C =     6.2415093×10^18 protons or electrons (or other charged particles) [fixed]

    We use Amps as the flow (like gallons per Hour) and Amps*Hours (AH) like an amount (total gallons pumped).

    Watts is similar... Watts is a rate of energy usage. Watt*Hours is the total amount of energy usage.

    In normal day to day usage around here, Amps per Hour and Watts per Hour are not used.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jonr
    jonr Solar Expert Posts: 1,386 ✭✭✭✭
    edited July 2018 #4
    Sticking to the datasheet is the proper, safe thing to do.    While I suspect you could go a bit higher, I've also heard that faster charging requires longer absorb - so you don't get a proper full charge much faster.

    If you don't have a MPPT controller with current limiting, you might use a clamp on ammeter to see what you are actually getting (perhaps less than you think).

    I am available for custom hardware/firmware development

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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited July 2018 #5
    BB. said:

    Amps is a "rate" already.  One coulomb of charge going past a given point per second.

    1 C = 6.2415093×1018 protons or electrons (or other charged particles)


    -Bill
    Sure a typo or something, formula should read 6.2415093 × 10 to the power 18 or 1 000 000 000 000 000 000,  6.24 quintillion

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #6
    I forgot this forum software does not handle sub/superscritps...

    1 C = 6.2415093×10^18 

    Just a cut and paste from a Wiki...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #7
    Did the copy paste with same results, hence the manual input. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
    · Share on Twitter

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