Got me the Eve 280ah LiFeP04 cells. Bought 2021 thru 2023

tampasolar
tampasolar Registered Users Posts: 90 ✭✭
edited May 27 in Old Battery Tech Discussions #1
Haven't been able to find solid info on how to balance and top off these Eve 280ah cells.
The bank has 17 cells.  Got the jkbms 2 amp balancer to monitor each cells voltage.
What I don't know is the right time to let the balancer run.
I heard to wait until cells are above 3.45 volts.
We are told not to do the Lead Acid Equalize function, ever.
What voltage do I take the top cell to ?  3.65 volts ?
Do I allow 3.9 volts if the lowest cell is below 3.65 volt ?
If anyone can link to a really good webpage with all this info it would be great.

hybrid: two xw6848 pro with five mppt60, 13 kw pv
17 cell Eve 280ah LiFePO4 storage  14 kw (now at 3 banks) total 40 kw
gridtie: sunny boy sma 2x 5k
Gateway / Insight Local

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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,196 ✭✭✭✭✭
    #2
    You only use 16 cells for a 48 volt battery bank you need to bring them up individually to 3.65 volts and no more ever and you do this generally with a bench power supply 16 of those cells will give you 51.2 volt nominal One extra cell Would be good in case you find a bad one
    https://www.youtube.com/watch?v=x5ABvbbics8

    When you open this link click on the orange Rectangle the top right of the page For the PDF
    https://diysolarforum.com/resources/top-balancing-lifepo4-cells-using-a-low-cost-benchtop-power-supply.65/

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • SumPower
    SumPower Registered Users Posts: 141 ✭✭
    #3
    Added the pdf from the link so you don't have to sign in to get the information.
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  • SumPower
    SumPower Registered Users Posts: 141 ✭✭
    edited May 28 #4

    The following is based on a 16s battery, not 17.
    3.55V is a conservative max charge voltage and a top balance start voltage of 3.45V is reasonable. 


    So basically you start balancing in the knee of the voltage curve. Which the 3.45 volts is the starting point for this. 
    You need to be in the knee to top balance.

    Edit: you may need to charge at a higher voltage to get balanced, but 3.65 Volt range is time to watch closely, I have very little experience with this, but I would not leave the batteries unattened at this voltage and I wouldn't let them sit to long at a voltage of 3.55 or more. They need to go to float so they can settle to float voltage, float should be around 3.375V. Follow the manufacturers guidelines for charging voltage.

    Getting the batteries balanced at the beginning of installation is the starting point and takes some patience.




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