I'm wondering if anyone has insight into the issues I've found before I plague Jason. I've just put together two paralleled 2P8S batteries using Eve 280AH LiFe cells, each with a separate port Chargery 16T v4.05 BMS and two DCCs. This is my first LiFe build, and it will first replace my 24V FLA battery bank and later be reconfigured as two 16S batteries, paralleled, when I replace my 22 year old Trace 4024 inverter/charger with a 48V inverter. The Eve cells came from Amy at Shenzen Luyuan and from the specs (and measured voltages) were extremely well matched, so I didn't top balance. The bank is only connected to a 10A power supply. The wiring is as shown in the DCC manual's diagram for separate port configuration with two 8S batteries.
The first oddity is that (even) with the power supply off, both BMS displays show charging current. Battery 1 shows 4.6A and battery 2 shows 3.5A. With the power supply on at 10 amps that goes up to 9.2 and 8.7 respectively. So battery 2 is taking a bit more current. The resistances should be identical since the batteries are constructed identically except for some minor differences in cable lengths going to the bus bars. All connections are tight although I didn't use a torque wrench. One side effect of this issue is that I can't put the BMSs into storage/sleep mode. I have to turn them off to save power.
Second, both display units show all cell resistances to be 0. So that feature just doesn't seem to be working. Bug, or related to my configuration? I know the paralleled pairs of cells are seen as single cells by the BMSs. So I would think it would still yield a resistance measurement, but I'm pretty ignorant about how that works.
Perhaps related, battery one began alarming after one day of charging due to differential voltage exceeding the 30mv default threshold. It turned off the discharge DCC. Typically when charging, the delta ran about 39mv and one cell pair was clearly the outlier, consistently high. Tomorrow I'll measure the voltages of each cell separately during charging. With charging off, both batteries have differentials around 10mv. I raised the threshold to 40mv to stop the alarming.
This may warrant a separate thread, but does anyone know if it is OK to use the charging function of the inverter/charger with a separate port system? I hadn't considered this when I ordered, and had not seen the diagram in the DCC manual showing the charge DCC being common port. Seems to me that the inverter/charger will charge the batteries but can't be shut down by the BMS since current will be feeding in through the discharge bus.
Thanks to Steve S for the great job on the manual! That must have been quite a chore.
Steve P
The first oddity is that (even) with the power supply off, both BMS displays show charging current. Battery 1 shows 4.6A and battery 2 shows 3.5A. With the power supply on at 10 amps that goes up to 9.2 and 8.7 respectively. So battery 2 is taking a bit more current. The resistances should be identical since the batteries are constructed identically except for some minor differences in cable lengths going to the bus bars. All connections are tight although I didn't use a torque wrench. One side effect of this issue is that I can't put the BMSs into storage/sleep mode. I have to turn them off to save power.
Second, both display units show all cell resistances to be 0. So that feature just doesn't seem to be working. Bug, or related to my configuration? I know the paralleled pairs of cells are seen as single cells by the BMSs. So I would think it would still yield a resistance measurement, but I'm pretty ignorant about how that works.
Perhaps related, battery one began alarming after one day of charging due to differential voltage exceeding the 30mv default threshold. It turned off the discharge DCC. Typically when charging, the delta ran about 39mv and one cell pair was clearly the outlier, consistently high. Tomorrow I'll measure the voltages of each cell separately during charging. With charging off, both batteries have differentials around 10mv. I raised the threshold to 40mv to stop the alarming.
This may warrant a separate thread, but does anyone know if it is OK to use the charging function of the inverter/charger with a separate port system? I hadn't considered this when I ordered, and had not seen the diagram in the DCC manual showing the charge DCC being common port. Seems to me that the inverter/charger will charge the batteries but can't be shut down by the BMS since current will be feeding in through the discharge bus.
Thanks to Steve S for the great job on the manual! That must have been quite a chore.
Steve P