L’ensemble fonctionnait parfaitement en mode autonome.
J’ai voulu passer en ESS. J’ai suivi les recommandations de Victron.
J’ai maintenant un comportement anormal : les batteries sont à 50,2V mais indique qu’elles sont chargées à 100% et donc elles ne se chargent pas.
Où est le problème?
No problem.
Depending on the system state, the battery can be indeed charged to 100%, but because the battery wants 0 (zero) amps charging current (that ESS #3), the system let the battery be.
Then the battery voltage is slowly decreasing to the idle voltage or up until the battery needs a top up.
Look below my Pylons in such a state, with a voltage similar to yours.
Indeed it’s on a discharging curve, with negative current, but it can be in the same state with 0A current.
So, don’t worry, all is OK, that 100% is reported by the battery BMS and the Pylontech BMS knows what’s doing.
Everytime any cell is reaching max voltage the BMS considers the battery as 100% and stop bulk charging. Afterwards it continues to charge at low rate. But 50.2 is too low for bulk charging even for LiPo so the problem is a cell or the BMS has a problem of connection with one of the cells.
Lets say you consider 100% of a cell charge at 3.6V this means the battery would be 57.6 if all cells are ideally charged in the same time. Anything lower than 55V at full charge I consider there is a BMS/cell related problem. Also some BMS-es are slow to equalize the voltage of the cells that some times are the bad link in the chain for fast charge discharge because the problem gets bigger at every cycle. If you charge in 3 hours to 50.2 and then in 6 hours or more the battery reaches 55V this battery is not usable in solar related scenarios.
Verify every time it goes 100% which cell is reaching max voltage first. If it is the same cell then there is the problem of connection (screw/wire), cell (bad cell) or BMS (slow or incapable to equalize the cells in a useful timeframe).
I hope this helps.
Oh, ok. The reasoning is there to be used for 15 cells.
If the first charged cell is 3.6v then the ideal pack would be 54v at the top charging point and float at 52v minimum - the producer should state both or it can be find/calculated in BMS data.
Succes!
