Hi all,
I have a question concerning the balancing of the cells in the Lithium NG batteries.
We always put two 200Ah batteries in series to have a system voltage of 48V.
The sticker on the batteries, and the manual tells us to completely charge the battery before putting it in use. We do this with a Smart IP43 Charger and a SmallBMS.
It takes quite some hours of time, and multiple charger restarts, to get them in the “balanced” state. Sometimes, all cell voltages are equal, but the battery is still indicating “balancing” or “imbalance”.
Once the system is in use and after a couple of days, one or more batteries are already stating “imbalance”. Even if we change the settings in the BMS so that absorption phase (56,8V) is triggerd every day for 8 hours, it is still difficult to get those batteries in the “balanced” state.
Anyone else having the same experience?
Thanks
[moderator note: I’ve changed the title to accurately reflect the batteries you have - the Lithium NG line is distinctly different than the Lithium Smart line, so want to be sure you’re getting advice relevant to the new NG product line]
I have a very similar issue, and while my system is 12v (6 x 200 in parallel - professionally installed May 2023) I have one battery (#4) that is “imbalance”. While in BULK, DISCHARGE and FLOAT state, all 4 cells read similar charge level (between 3.34 and 3.35 per cell), however when the bank enters ABSORB, cell 1 remains at 3.35 while cells 2, 3 & 4 jump to 3.60, 3.65, and 3.63 respectively, battery temperature rises to 49c and the battery monitor label says “balancing”. This same behavior repeats every ABSORB cycle, although once the cycle ends, the battery label returns to “imbalance”.
The control panel indicates the last full charge for this battery was 17 days ago, although the other five batteries in the parallel array all indicate the last full charge was just hours ago.
I’m at a loss on how to bring this back into balance.
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I would limit the charging voltage to a value that will not allow any cell to go over 3.6V and keep the batteries at that voltage up until all cells are in balance. All voltages, bulk, absorption, float, set to the same voltage, probably to about 14V which is about 3.5V per cell.
Even after multiple days of repeatedly absorption charging at 56,8V for 8h in a row, we still have one cell that is a lot lower in voltage than the others. Brand new batteries, slowly charged to absorption voltage directly after arriving from the distributor.
I would contact your dealer about the battery if the balance is not improving. They are new and best to raise the issue sooner rather than later.
