Charging individual lithium04 battery packs in a bank

spacebass
spacebass Registered Users Posts: 87 ✭✭
edited December 2019 in Solar Beginners Corner #1
I have 4 12v lithium 04  pre made plastic battery packs in a 48 volt bank can I charge each battery separately with the supplied 12volt charger obviously using the charge socket on each battery while connected as a bank or do I have to separate them. 
I have just run them overnight and they ran out of juice any tips on getting them charged up ?
The individual batteries are not at the same state of depletion . Do I need s BMS type device to balance the 4 battery packs if so what?
I also have a 24 volt system that I intend to switch to on the depletion of the 48 volt system (I hope) but have not put the switch in yet. I do that tomorrow .
Thank You.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #2
    What is the Amp*Hour ratings of your batteries? And what are you overnight loads (Watts/Amps@48 volts/etc.)?

    Are those batteries (wth some sort of BMS) rated to run 4x in series @ 48 volts?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • spacebass
    spacebass Registered Users Posts: 87 ✭✭
    #3
    BB. said:
    What is the Amp*Hour ratings of your batteries? And what are you overnight loads (Watts/Amps@48 volts/etc.)?

    Are those batteries (wth some sort of BMS) rated to run 4x in series @ 48 volts?

    -Bill

    Hi Bill ,
    The batteries are 120ah, it says on the battery has advanced protection (in Chinese).
    I don't know if they are 'rated to run in series at 48 volts' , I have run two pairs at 24 volts for a couple of weeks with no problems. One pair runs my big fridge for 14 hours.
    I am measuring tonight 12 hours main load which is 2 inverter fridge freezers one 7.7 cu ft one 14.2 cu feet. I also have two fans about 28'watts each and modem / router internet.

    I will post tomorrow consumption of two fridges 12 hours overnight

    Thank You.




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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #4
    Without knowing the chemistry it's impossible to answer a question with such vague details. The purpose of a BMS is to keep cells within a battery (a group of cells in series ) within  safe parameters, there is no BMS which monitors batteries connected in series, parallel or otherwise,  each would have its individual BMS unless it an engineered system with communication capabilities.

    Be very careful when dealing with lithium batteries, some are very unforgiving should one venture outside safe parameters, if in doubt, don't, is the best advice I could offer at this stage.


    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.  
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  • Raj174
    Raj174 Solar Expert Posts: 795 ✭✭✭✭
    #5
    I would advise charging them individually to 100% then connect them in the series configuration. It's important that they all have very close to equal voltage.
    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
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  • spacebass
    spacebass Registered Users Posts: 87 ✭✭
    #6
    Raj174 said:
    I would advise charging them individually to 100% then connect them in the series configuration. It's important that they all have very close to equal voltage.

    I have been doing that so far and will continue Thank You.

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  • spacebass
    spacebass Registered Users Posts: 87 ✭✭
    #7
    mcgivor said:
    Without knowing the chemistry it's impossible to answer a question with such vague details. The purpose of a BMS is to keep cells within a battery (a group of cells in series ) within  safe parameters, there is no BMS which monitors batteries connected in series, parallel or otherwise,  each would have its individual BMS unless it an engineered system with communication capabilities.

    Be very careful when dealing with lithium batteries, some are very unforgiving should one venture outside safe parameters, if in doubt, don't, is the best advice I could offer at this stage.

    The question has become redundant as I have just ordered a 48 volt 5amp Lp04 charger .

    As. a matter of nterest my 2 inverter fridge freezers 7.9 and 14.2 cu. ft used 11.5 kWh over 7 days.


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