How do you get LiFePO4 matched prismatic cells?

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MontyYoung
MontyYoung Registered Users Posts: 12 ✭✭
edited March 2020 in Solar Beginners Corner #1
I'm looking to get some CALB, SP, or winston 180AH cells for 4 4S batteries in parallel for a small 12V cabin setup, & I hear guys getting these well matched cells but how exactly? I also don't wan't a balancing BMS at all and prefer to manually balance. As I read some sources of info online, matched means AH capacities within under 1% of each other, isn't this asking too much?
Can I buy online from places like ev works & gwl & expect to get macthed cells? what about ebay or alibaba?

edit: I meant ev works, not ev power.

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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
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    The better the matching, the less babysitting you do on the bank.   And if you had a 300ah bank, and one cell was 20% low, you now have a 240ah bank.  Or they may be only 5ah different.  Your guess is as good as mine

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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    #3
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    Being like lot numbers would likely be the best, the capacity variables  of 1% would be of little concern since when in operation they shouldn't be charged or disharged completely to to extend service life.

    Typically 90 to 20% state of charge is recommended, once ballancing is performed by charging all cells in parallel to 3.650 V, the maximum   thereafter  would be limited to~3.500V per cell bulk for a short duration, <10 minutes, then float at ~ 3.375 V per cell by the charge controller. With these settings a BMS with ballancing would not be able to ballance due to the limited charge voltage, having a means of disconnecting the load automatically to prevent over discharge is more important, which is what a good BMS should do.
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  • Battery_Man
    Battery_Man Registered Users Posts: 6 ✭✭
    #4
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    MontyYoung said:
    I'm looking to get some CALB, SP, or winston 180AH cells for 4 4S batteries in parallel for a small 12V cabin setup, & I hear guys getting these well matched cells but how exactly? I also don't wan't a balancing BMS at all and prefer to manually balance. As I read some sources of info online, matched means AH capacities within under 1% of each other, isn't this asking too much?
    Can I buy online from places like ev works & gwl & expect to get macthed cells? what about ebay or alibaba?

    edit: I meant ev works, not ev power.

    Hi, the cell matching should reply on the supplier in terms of IR difference, volt. difference and capacity difference based on your PACK configuration, such as how many cells in parallel and how many cells in series. There may be some good cells in ebay or alibaba, while also mixed with lots of bad cells there. So better to buy from supplier with factory support and never buy from battery trader, no matter what kind of cell brand you are looking for.
    Who am I?
    → Officially and exclusively authorized agent of CALB battery in China. CALB is a leading battery manufacturer in China and the leading brand in the world.
    Contact mail?
    → Alvinsun02@hotmail.com or Alvin@fj-calb.com

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