Hello,
I have been researching the best way to top-balance my cells (4x 280A) and came to the conclusion that most of the people connect the cells in parallel and charge them up to 3.65V with a regulated PSU.
Story why it would take me so long:
I have tried it with my 5A (set at 4.5A) PSU and it obviously will take ages. In additon it will take even longer, since I do not want to leave the PSU + Cells unsupervised (Fan already turned off at one time and the PSU nearly overheated). I have already charged one cell for around 15h from 3.28V up to 3.31V which is roughly 65-75% Soc and although the charging curve will become steeper, charging all four cells under supervision will take me ages because of my limited free-time. Money is short - buying a reasonable bigger PSU just for this purpose makes no sense for me.
Alternative idea to top-balance after some research:
I have read about another option to top-balance in a detailed article on a marine-website which takes way less time but is more labor extensive and requires full-supervision.
(I am not sure if I am allowed to post external links - please advise and then I include the link here)
It basically consists of charging up the batteries up to ~3.6V as a pack (12V bank) and then disconnect the cells and charge them up to 3.65V individually.
In this article the person directily connected it to the boat's alternator (supplying ~14,4V) and monitored each cell regulary and turning the system of if one cell hits 3.6V.
My adaption of this way:
I already have my Victron Multiplus 12/800 which can act as a battery-charger ("charger-only" mode) supplying up to 35A to a battery-bank.
One cell sits now at 3.31 (obviously will be full at first) and the rest sit at 3.28V.
My steps would be:
1) Connect the cells in series (4s - 12V )
2) Charge the battery with the Multiplus up to 14,4V (cut off voltage) and monitor each cell constantly with a multimeter
3) Turn off if one cell hits 3.6 or lets say 3.55V
4) Individually charge the cells up to 3.65V with a regulated PSU
My questions:
Q1: What do you think about this alternative methode?
Q2: Is it even safer if I connect the BMS to the battery and let it do the cut-off if one cell reaches 3.6V?
Thank you in advance.
I have been researching the best way to top-balance my cells (4x 280A) and came to the conclusion that most of the people connect the cells in parallel and charge them up to 3.65V with a regulated PSU.
Story why it would take me so long:
I have tried it with my 5A (set at 4.5A) PSU and it obviously will take ages. In additon it will take even longer, since I do not want to leave the PSU + Cells unsupervised (Fan already turned off at one time and the PSU nearly overheated). I have already charged one cell for around 15h from 3.28V up to 3.31V which is roughly 65-75% Soc and although the charging curve will become steeper, charging all four cells under supervision will take me ages because of my limited free-time. Money is short - buying a reasonable bigger PSU just for this purpose makes no sense for me.
Alternative idea to top-balance after some research:
I have read about another option to top-balance in a detailed article on a marine-website which takes way less time but is more labor extensive and requires full-supervision.
(I am not sure if I am allowed to post external links - please advise and then I include the link here)
It basically consists of charging up the batteries up to ~3.6V as a pack (12V bank) and then disconnect the cells and charge them up to 3.65V individually.
In this article the person directily connected it to the boat's alternator (supplying ~14,4V) and monitored each cell regulary and turning the system of if one cell hits 3.6V.
My adaption of this way:
I already have my Victron Multiplus 12/800 which can act as a battery-charger ("charger-only" mode) supplying up to 35A to a battery-bank.
One cell sits now at 3.31 (obviously will be full at first) and the rest sit at 3.28V.
My steps would be:
1) Connect the cells in series (4s - 12V )
2) Charge the battery with the Multiplus up to 14,4V (cut off voltage) and monitor each cell constantly with a multimeter
3) Turn off if one cell hits 3.6 or lets say 3.55V
4) Individually charge the cells up to 3.65V with a regulated PSU
My questions:
Q1: What do you think about this alternative methode?
Q2: Is it even safer if I connect the BMS to the battery and let it do the cut-off if one cell reaches 3.6V?
Thank you in advance.
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