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electrical:12v:drop-in_lifepo4

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electrical:12v:drop-in_lifepo4 [2022/06/16 23:08]
frater_secessus [myth: you have to charge Li to 100%]
electrical:12v:drop-in_lifepo4 [2022/06/16 23:16] (current)
frater_secessus [cell balancing]
Line 386: Line 386:
     * cell 2 = 3.400v     * cell 2 = 3.400v
     * cell 3 = 3.400v     * cell 3 = 3.400v
-    * cell 4 = 3.**500v** <-- balancer will try to slow this one down+    * cell 4 = 3.**500v** <-- a "passive" balancer will try to slow this one down((an "active" balancer would steal from the rich (#4) and give to the poor (#1))
  
 In both cases the overall battery voltage is 13.6v, but in the unbalanced battery cell #1 is lagging (reducing capacity) and cell #4 is too high.  The balancer will attempt to rein in #4 but the effect is tiny.  Using a typical balancing current of 50mA, if you are charging at 20A that means the cells are receiving 5A except cell #4 which gets only 4.95A, about a 1% difference.  Tiny balancing currents and the propensity of cells to race away explains why balancing is so gradual. In both cases the overall battery voltage is 13.6v, but in the unbalanced battery cell #1 is lagging (reducing capacity) and cell #4 is too high.  The balancer will attempt to rein in #4 but the effect is tiny.  Using a typical balancing current of 50mA, if you are charging at 20A that means the cells are receiving 5A except cell #4 which gets only 4.95A, about a 1% difference.  Tiny balancing currents and the propensity of cells to race away explains why balancing is so gradual.
electrical/12v/drop-in_lifepo4.txt ยท Last modified: 2022/06/16 23:16 by frater_secessus