I am charging a 12V LifePo4 battery with a 14,6V LifePo4 charger (2 Amps). The battery has 4 LifePo4 cells (60Ah) hooked to a Daly smart BMS and a solar charge regulator PWM (battery connections). In the same battery connections of the PWM I have connected the charger which therefore can supply energy directly into the battery. PWM is intended for battery discharge and voltage visualization without Daly BMS app.
The charging goes smooth and whenever the voltage difference of the cells reaches 0,05V, the auto-balance function kicks in and reduces it to 0,01V.
When the battery reaches charge of 99% it stays there for a couple hours and then the behavior of the system changes.
After 2 hours of constant charging at 99% SOC, charging begins to be intermittent; furthermore, while the SOC remains at 99%, the battery voltage difference keeps growing over time regardless of the balancing function being activated. Eg. Voltage difference overserved = 0,12V.
I think that the SOC remains at 99% because the battery voltage according to Daly app is 14,2V; it remains under the SOC 100% voltage of 14,6V; but why does the last 1% of charging goes so slow? (Battery stayed 3 hours at 99% in which 2 the charging was constant and at 19W)
Then, why does the voltage difference keeps increasing over time? Is the voltage of full cells more difficult to balance? Could this have something to do with the fact that the cells are from Litokala Aliexpress and probably have been used already?
After one hour of intermittent charging and the voltage difference getting as high as 0,12V I have stopped the charging afraid of "destabilizing" the battery. Two cells were around 1,6V and two around 1,5V; charging just kept increasing its voltage slowly.
Since in the theory cell voltage can go as high as 3,65V I though that maybe I could let the charging process continue. But then I was concerned about voltage battery being 14,2V in the Daly app and 14,7V in the PWM display. At which charging voltage can I start damaging the LifePo4 cells? I think however it is just the PWM measuring bad.
When I disconnected the charger, the voltage of the battery and cells went way down to 13,3V (3,35V per cell) and the voltage difference became as low as 0,005V which got me thinking that maybe I could have safely left the charging ongoing to reach the 100% while ignoring the voltage measured by the PWM. The PWM seems to measure always a higher battery voltage. The charger I have should stop charging at 14,6V as it is made for LifePo4 battery charging.
Some volunteer to give me green light on 100% SOC charging despite the observations?
The charging goes smooth and whenever the voltage difference of the cells reaches 0,05V, the auto-balance function kicks in and reduces it to 0,01V.
When the battery reaches charge of 99% it stays there for a couple hours and then the behavior of the system changes.
After 2 hours of constant charging at 99% SOC, charging begins to be intermittent; furthermore, while the SOC remains at 99%, the battery voltage difference keeps growing over time regardless of the balancing function being activated. Eg. Voltage difference overserved = 0,12V.
I think that the SOC remains at 99% because the battery voltage according to Daly app is 14,2V; it remains under the SOC 100% voltage of 14,6V; but why does the last 1% of charging goes so slow? (Battery stayed 3 hours at 99% in which 2 the charging was constant and at 19W)
Then, why does the voltage difference keeps increasing over time? Is the voltage of full cells more difficult to balance? Could this have something to do with the fact that the cells are from Litokala Aliexpress and probably have been used already?
After one hour of intermittent charging and the voltage difference getting as high as 0,12V I have stopped the charging afraid of "destabilizing" the battery. Two cells were around 1,6V and two around 1,5V; charging just kept increasing its voltage slowly.
Since in the theory cell voltage can go as high as 3,65V I though that maybe I could let the charging process continue. But then I was concerned about voltage battery being 14,2V in the Daly app and 14,7V in the PWM display. At which charging voltage can I start damaging the LifePo4 cells? I think however it is just the PWM measuring bad.
When I disconnected the charger, the voltage of the battery and cells went way down to 13,3V (3,35V per cell) and the voltage difference became as low as 0,005V which got me thinking that maybe I could have safely left the charging ongoing to reach the 100% while ignoring the voltage measured by the PWM. The PWM seems to measure always a higher battery voltage. The charger I have should stop charging at 14,6V as it is made for LifePo4 battery charging.
Some volunteer to give me green light on 100% SOC charging despite the observations?