JKBMS US EU Stock Smart BMS Balancer B2A20S20P 7~20S 200A 2A Smart Active Balancer LFP Li ion LTO Lifepo4 Balancer RS485 BT APP

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Description

 

NOTICE:
If you need to use BMS in parallel,
Fast Class T Fuse must be added to each battery pack.
Or discharge diode (high power diode selected according to load)
Provide a diagram (thanks to members of diysolarforum for sharing).

Protection (Current Sensor Anomaly)
This problem exists when the inverter is used, because the current direction is uncertain,
The alarm will be displayed. It does not affect the normal use of BMS.
This kind of alarm will appear when the sun is not big or small, because at this time,
the battery fluctuates frequently between charging and discharging,
and there are uncertain factors, so this problem occurs.

A pure sine wave inverter does not draw a constant current. The current from the battery follows a sine wave shape.
It ramps from zero current up to peak current in 1/4 of a cycle.
The peak current is actually about 40% more than the average current.
Then the current will ramp back down to zero at the 1/2 cycle time. At this point, the inverter reverses polarity,
and ramps the current back up again, hitting the peak at the 3/4 cycle time. The battery current is positive again,
and the inversion happens in the inverter circuit. The the current ramps down back to zero again at the end of the cycle.
The process them repeats for every cycle.

If you measure with an averaging meter, you will just see a fairly steady current that should be close to the true RMS current.
I use a True RMS Fluke meter, and it is able to give a vey accurate reading on this odd waveform.
The current reading in the BMS just measures the voltage across a shunt resistor. This reading is only taken periodically,
and it is not synced the the changing current from the inverter. It might take a reading at zero current, or at the peak current,
but most likely, it will fall somewhere in between.
Due to the shape of the wave, the reading tends to bounce a bit above and below the true RMS current.
It is not perfect, but over the long term, it is "good enough" for the BMS to calculate the amp hours charged in or discharged out of the battery.
This works because if you average the readings over a full hour, the high and low readings will average out.