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Battery still taking charge AFTER hit 100% SOC ?

new off grid

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Jan 27, 2020
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Hello every one,
Just finished my 48V off grid system , so far so good, the only thing I'm not sure is that , the battery looks like still taking charge after it hit 100% full
Anyone ever been thru this situation ? Thank you so much for all your help. Attached is the BMS screen shotSTILL CHARGE AFTER HIT 100%.PNG
 
Initial SOC when you just commissioned a new system means nothing, it's just a number stored in BMS memory, it has nothing to do with actual battery SOC. When you finish your first full charge by actually reaching target voltage with a short absorption stage at the end, that is when actual SOC will be in sync with calculated or estimated SOC in BMS's "brain". From that point on BMS will track AH in and out of the battery and adjust the estimated SOC to try and match with real SOC. It's called Coulomb counting.
 
Wow, thank you so much Electric, it's all clear now.This's just my 2nd cycle of the brand new system battery !!!. So I think I'll discharge it all the way to Zero, and charge it back all the way to 100% to help the BMS " learn" how to do its job, hopefully everything is OK. Thanks again Electric,
The rest of my setup :
- 375w REC solar panel x 9 ( Total 3325 w )
- Midnite Classic 150 Charge controller
- Meritsun 48v/200AH Lifepo4 battery Powerwall ( Total 10Kwh )
- 48v/7000w/120ac Reliable Inverter
So far test running around 4500-5000w simulaneously for around 1 hour is very smooth and stable
 
a cell is charged at 3.65V , but you can push it to 4.1V (while the benefits of doing that seems less than the wear your put on the battery).
so if you apply conservative charging, your cell is actually not charged 100%.
 
a cell is charged at 3.65V , but you can push it to 4.1V (while the benefits of doing that seems less than the wear your put on the battery).
so if you apply conservative charging, your cell is actually not charged 100%.
A cell is charged at 3.40V, or anywhere from 3.40V to 3.65V. The only difference is a time factor and the charge rate.
Also, 100% is a number that only has meaning to whoever designed the battery system and configured the SOC gauge. You draw a line in the sand and state - this is my 100%. Obviously at or below the actual physical charge limit of your cells.
 
Wow, thank you so much Electric, it's all clear now.This's just my 2nd cycle of the brand new system battery !!!. So I think I'll discharge it all the way to Zero, and charge it back all the way to 100% to help the BMS " learn" how to do its job, hopefully everything is OK. Thanks again Electric,
The rest of my setup :
- 375w REC solar panel x 9 ( Total 3325 w )
- Midnite Classic 150 Charge controller
- Meritsun 48v/200AH Lifepo4 battery Powerwall ( Total 10Kwh )
- 48v/7000w/120ac Reliable Inverter
So far test running around 4500-5000w simulaneously for around 1 hour is very smooth and stable

Since this is a new system pay close attention to your bottom (ZERO) and make sure you do NOT go past the minimal discharge rate for your battery ... There is really no need to run it to zero at all ...
 
Thank you, everyone ! Understand some more now, Just down to 0% SOC once , and now the BMS says " Low Capacity " @ 11% SOC. It did not Alarm that before, so I think the BMS woke up and do what it supposed to do.
You guys are so great, have a very nice day !!
 
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