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opinion:frater_secessus:charging_faster [2020/06/07 18:55]
frater_secessus [lead-acid]
opinion:frater_secessus:charging_faster [2023/07/15 11:05] (current)
frater_secessus [lithium]
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   * charging AGM at C/5 (min rate) resulted in the battery being 77.4% "full" at Vabs and being fully charged in **5hrs, 42 minutes** (76min Bulk, 4hr 26mins Absorption)   * charging AGM at C/5 (min rate) resulted in the battery being 77.4% "full" at Vabs and being fully charged in **5hrs, 42 minutes** (76min Bulk, 4hr 26mins Absorption)
  
-Note that the **using 2x the charging current only sped up the whole process by 12 minutes (3.6%)** due to Vabs starting earlier but taking longer. Getting to Vabs faster could be [[electrical:solar:pwm_tweaking|preferable on PWM controllers]]+Note that the **using 2x the charging current only sped up the whole process by 12 minutes (3.6%)** due to Vabs starting earlier but taking longer. 
  
-Also note that for simple, timer-based Absorption configurations((like 180 minutes)) the slower charging regiment would actually complete more Absorption.((180/266mins rather than 180/310mins))+  * **Getting to Vabs faster** could be [[electrical:solar:pwm_tweaking|preferable on PWM controllers]]as the system would be making max power for a longer period of time. 
 +  * **Getting to Vabs slower** could be preferable on timer-based Absorption configurations((like 180 minutes)), as slower charging regiment would reduce the required Absorption duration.((180/266mins rather than 180/310mins))
  
  
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-**Lithium batteries** can slurp up current wildly, but shouldn't for their own health.  Lithium lasts longest in sub-C use (ie, less than 100A for a 100Ah Li bank).  C/2 (50A) is a more common limit to keep from stressing them. In commercial examples the BMS will limit current to protect the cells.  A small [[electrical:12v:b2b|DC-DC charger]] can help protect bare cells from their own greediness.+**Lithium batteries** can slurp up current wildly, but shouldn't for their own health.  Lithium lasts longest in sub-C use (ie, less than 100A for a 100Ah Li bank).  0.5C (50A) is a more common manufacturer recommendation, and folks [[electrical:12v:drop-in_lifepo4#an_approach_to_greater_longevity|striving for added longevity]] might limit it to 0.2C (20A). There is some evidence that 0.4C rates are acceptable for long life when combined with gentle charging voltages like 3.45Vpc.((FIXME  - insert Rod's testing of 2011 bank here)) 
 + 
 +In commercial examples the BMS will limit current (typically to 1C) to protect the cells.  A small [[electrical:12v:b2b|DC-DC charger]] can help protect bare cells from their own greediness. 
 + 
 + 
 + 
 +Limiting charging  current also makes it easier on alternators when they are used to charge Li.  
  
  
opinion/frater_secessus/charging_faster.1591570522.txt.gz · Last modified: 2020/10/11 19:48 (external edit)