Hello! Thanks already for the info! I got a bit lost in the forum I don't find any example for my system. I got 12 winston 100ah, 3,5v Lifepo4 cells. I'm now top balancing them. The idea is to make a batterypack of 300 ah. I got one (250A)daily bms 3p4s. Anybody knows how to order the cells and how to connect my bms? Kind regards pieter
300ah lifepo4 battery with 12 winston lifepo4cells of 100 ah
- Thread starter Pie
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3.5V? Are they LiFeYPO or LiFePO4? You need to set the BMS properly for the selected chemistry
For connection: What is not clear? Using a single 4S BMS makes you need to do 3P4S. Just wire the balance leads to all 4 sets of cells as you would if it was a single string
For connection: What is not clear? Using a single 4S BMS makes you need to do 3P4S. Just wire the balance leads to all 4 sets of cells as you would if it was a single string
Daly provides schematics with their BMS.
You only need to use the correct diagram depending if you have a common or seperate port BMS.
But you first need to clarify the cells. There are NO 3.5V LiFePO4 cells. It's either 3.2V (LiFePO4) or 3.3V (LiFeYPO), Winston makes both afaik.
If they cells do require different voltage you need to adjust the BMS to match the cells, so please provide a datasheet of the cells.
You only need to use the correct diagram depending if you have a common or seperate port BMS.
But you first need to clarify the cells. There are NO 3.5V LiFePO4 cells. It's either 3.2V (LiFePO4) or 3.3V (LiFeYPO), Winston makes both afaik.
If they cells do require different voltage you need to adjust the BMS to match the cells, so please provide a datasheet of the cells.
Why topbalance to 3.3V? LiFeYPO tends to be more towards 3.8-4V on the top side
Just check the datasheets of your specific cells.
Since it looks you're not familar with chemistries and cell balance voltages, i'd highly recommend upgrading your knowledge first before starting any topbalancing at all. (or any work in generic for this battery project). It's the recipe for disaster or damaging your expensive cells.
Also, some basic knowledge is required or at least highly recommended.
Remember, getting a nice DIY bank for $2000 instead of $4000 for a commercial is a huge saving.. But if you're messing up and pay $2k for scrap in the end... it's still a $2k loss and you would have been better of spending that initial $4k without all the DIY hassle
It's either spending money, or time/knowledge on DIY and confidence in your own skills. Its up to you what of these 2 you have the most.
Just check the datasheets of your specific cells.
Since it looks you're not familar with chemistries and cell balance voltages, i'd highly recommend upgrading your knowledge first before starting any topbalancing at all. (or any work in generic for this battery project). It's the recipe for disaster or damaging your expensive cells.
Also, some basic knowledge is required or at least highly recommended.
Remember, getting a nice DIY bank for $2000 instead of $4000 for a commercial is a huge saving.. But if you're messing up and pay $2k for scrap in the end... it's still a $2k loss and you would have been better of spending that initial $4k without all the DIY hassle
It's either spending money, or time/knowledge on DIY and confidence in your own skills. Its up to you what of these 2 you have the most.
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Topbalancing is usually done at the (near) highest allowed voltage of your cells.
For regular LiFePO that's 3.65V, so that is why people use that for topbalancing. 3.6V will work also.
Recommended regular working voltage is lower, while using 3.65V for topbalancing, its generally recommended to use lower voltages for regular use
LiFeYPO has a slightly different voltage curve, if I remember 3.8V. But without the datasheet of your specific cells no-one can recommend you a safe voltage.
Also, topbalancing: Don't make the common mistakes: Adjust PSU before connecting the cells to the proper voltage, use proper leads (many included leads with cheap chargers are crap), double check with a multimeter, never readjust voltage once cells are connected
For regular LiFePO that's 3.65V, so that is why people use that for topbalancing. 3.6V will work also.
Recommended regular working voltage is lower, while using 3.65V for topbalancing, its generally recommended to use lower voltages for regular use
LiFeYPO has a slightly different voltage curve, if I remember 3.8V. But without the datasheet of your specific cells no-one can recommend you a safe voltage.
Also, topbalancing: Don't make the common mistakes: Adjust PSU before connecting the cells to the proper voltage, use proper leads (many included leads with cheap chargers are crap), double check with a multimeter, never readjust voltage once cells are connected
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