JK BMS and DVCC

[ChiefSolar]

No, sorry. I’m not old enough, yet, to waste a perfectly good job As in I work as a contractor on projects and they won’t like it when I spill their beans.

[RGroothuis (Rene)]

No problem, thanks anyway. If i don’t ask I will never know. Have fun.

[Courage2000]

@jkoljo

You need the JK BMS app on your phone.

1. Connect to the BMS via Bluetooth
2. Go to the page with all the cell voltage settings and such. You may need to enter the password to be able to modify values.
3. Have a stable and high current flowing in or out of the battery. Measure the current with a reliable measurement method. The smart shunt is probably good enough. Another option would be a current clamp.
4. Enter that current to the “calibrating curr.” field and press ok. Done.
5. Verify that the calibration took by looking at BMS readings.
6. Proceed to do both discharge and charge currents. The system automatically determines the direction you are calibrating. You enter positive values to the amperage field in both situations.

My BMS was about 15A off (too much) when discharging at 70A actual, and 5A off (too much) when charging at 70A actual. After calibration it matches my DC current clamp with max error of about 1A.

I’ve identified some problems with this procedure:

1. How can I have a stable current when I have 6 parallel batteries on 3x Multiplus II 15000VA?
2. I need to disconnect and calibrate the voltage on each battery, but is connected to Lynx PowerIn
3. On each firmware update, all the values are reset, so I need to recalibrate all the batteries

NOT FUN, too much work, complicated procedure.

[jkoljo]

1. One at a time. Set to keep batteries charged → stable charging from grid. Also set a low grid current limit to not overload your battery / use DVCC limit.
2. Yes
3. Only update BMS if you really need some fixes in a newer firmware. Otherwise leave BMS alone.

Maybe it’s fun, maybe not. For me its a hobby. And faster to calibrate 6 batteries than change a waterpump or brake pads in my car for example.

[Zolko]

Hello, I have a problem with my Victron system. It contains 2 MPPT chargers, a BMV 702 and a cerbo gx. It also has a 200 Ah lifepo4 battery pack V19 jkpb2a16s15p BMS with CAN bus connection. My problem is that my MPPT controller does not want to switch from absorption charging to trickle charging, even though the 100% charge level is met. What could be the problem? DVCC is on. It doesn’t matter what I set as “Battery monitor” Bmv or BMS, it doesn’t switch.