Hello all,
First winter for my battery pack.
Using NodeRed, I would like to charge my battery from time to time through the grid to 100% to keep the cells balanced.
What is the best interval? Once a week? Once a month?
Thanks.
It would help to mention some details about your system, the battery in particular, to assist with generating a response…
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The answer about battery charging depends on your battery.
Some manufacturers want it once a month at least. Some once a week. Others once every 14 days. An neat average is 14days. Seems middling. Does depend on how cycling your cycles are though.
I have a BYD Premium LVL 15.4 to supply the household with electricity.
Charging with solar during the day, if there’s no sun from the grid.
Around 12KWh consumption each day.
The main issue that I’ve found from some battery suppliers is the balancing current used by their BMS systems is relatively low compared with the battery size - i.e. 100mA for 150 - 200Ah. So to balance the cells one needs to spend quite a time above 80 - 85%, with a trickle charge (controlled by the BMS thru DVCC). Other manufactures BMS use 1-3A per 150 - 200Ah, so balancing is relatively quick. You can keep a check on the state of the battery system through the difference between high and low cell voltages, if this is more than 50 - 100mV, then the balancing time need extending. Also keeping a check on the cell number that first reaches max cell voltage, and the cell number that reaches minimum voltage - this indicates also the state of the battery. If these cell numbers are the same,then you have a weak cell. If one cell hits low voltage well before the others, then this possibly has an internal discharge current - again worth watching. It is normal for one cell to hit the high voltage limit before the other cells, time taken for the remaining cells to reach full charge then depends on the balancing current.