Below FAQ is about BMS
1. Charge or Discharge relay/DC contactor won’t open (disconnect) or close (connect)
a) Confirm the relay coil driven voltage, it must be 12V.
b) Confirm relay coil current requirement, it must not be over 1A for each relay or that the total current with two relays won't be over 2.6A
c) Without alarm the charge and discharge relay controller voltage is 12V,
d) When any alarm events occurs, the charge and discharge relay controller voltage is 0V,
e) Without any warnings, the relay always closed
2. Cell voltage display is not accordance with actual cell voltage
a) Check 9 pin balance wire connections are good and secure.
b) Measure actual cell voltage on the BMS balance port.
c) Disconnect battery, measure resistance on balance port. Such as, if cell 5 voltage is not correct, measure resistance between cell 5- and 5+ on balance port. Generally it is very large (100K ohm or so).
d) Or send back to us and calibrate the cell voltage again.
3. SOC is zero,
a) Restart BMS main unit---power off it and power on again.
4. SOC is wrong
a) Setup accurate battery capacity on program setup interface
b) Charge or Discharge the battery. Charged capacity or Discharged capacity is 25% of battery rated capacity at least.
c) BMS will calibrate the SOC automatically after charge or discharge.
5. Charge or discharge current display is not stable or wrong
a) The wire length from current shunt to battery negative should be as short as possible.
b) Check charge current or discharge current ripple, especially on an inverter.
c) Add low-pass filter on current sensor
d) Update main unit to V1.21, do not need calibrate current.
e) If shunt is replaced, or for other reasons you need to calibrate current, the calibration video is here https://www.youtube.com/watch?v=_LOJw83s18M
6. Cell voltage difference drop slow during balance
a) Setup balance in Storage is ON
b) Setup balance in Charge is ON
c) Setup lower balance start voltage
d) Confirm the BMS main unit blue case is warm, if yes, it means the balance is in working. on V4.0, there is yellow indicator bar can indicate which cell is in balancing.
e) If a cell voltage is always lower than others, such as cell 5, please disconnect all battery and measure resistance between cell 5- and 5+ on balance port. Generally it is very large (100K ohm or so). If only 10 ohm or less, please return back to us for repair.
f) For over 50Ah battery, the balance time is longer relative to battery size
g) After discharge, check the cell voltage difference on LCD, if over 100mV even 200mV, it means the cell impedance difference or capacity difference is very large. Exchange lower voltage cell in discharge or higher voltage cell in charge is suggested.
7. STOP button freeze
a) When current displayed is ZERO, that is to say, the battery is not charging or discharging, press STOP button to make the BMS enter into sleep mode to save battery energy.
b) If you need wake up the BMS, please press UP, DOWN or START Button.
c) The STOP button will NOT stop an Inverter while drawing power and will NOT stop charging if there is current from the Charger. Loads & Charger must be OFF to allow the BMS to enter into Sleep Mode.
8. Show timeout during updating,
a) Download the correct firmware according to product model and save to your PC, from http://chargery.com/update.asp
b) Update tool software version must be v1.03 or greater. Always use the most current.
c) Connect BMS main unit or LCD unit to the PC by using the provided USB cable.
d) Turn on BMS main unit.
e) Execute update tool software and lock the com port by click OPEN button.
f) Click open file button and upload the correct firmware.
g) Click update button finish update.
9. Charging stops, the possible reasons are as below.
a) Any cell voltage reaches ―Over Charge Protection(P) Voltage― setting.
b) The highest cell voltage is over ―Over Charge Release(R) Voltage‖ setting.
c) Charging current is over ―Over charge current‖ setting.
d) Battery temperature is over ―high temperature cutoff‖ setting.
e) Battery temperature is under ―low temp cutoff in charge‖ setting.
f) Battery temperature difference is over ―diff of battery temp‖ setting.
g) Charger stop charging,
10. Discharging stops, the possible reasons are as below.
a) Any cell voltage reaches ―Over discharge Protection(P) Voltage ― setting
b) The lowest cell voltage is under ―Over discharge Release(R) Voltage‖ setting.
c) Discharging current is over ―Over discharge current‖ setting.
d) SOC under ―SOC----battery gauge‖ setting.
e) Cell voltage difference is over ―Difference(Diff) of cell voltage‖ setting.
f) Battery temperature is over ―high temperature cutoff‖ setting.
g) Battery temperature is under ―low temp cutoff in discharge‖ setting.
h) Battery temperature difference is over ―diff of battery temp‖ setting.
11. LCD back light is always ON, the possible reasons are as below. Within ―LCD Back-light time‖ setting
a) There are any warning events happened
b) Do any operations