JLG X390AJ-X14J Supplement Manual page 101

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3. Highest at: It is the voltage at the highest cell.
The number of the highest cell is indicated on
side.
During the Discharge: During discharge, this
value is not important, it is normal that the
decrease in cells voltage is different.
During the Charge: This is important data. Dur-
ing the charge, the highest cell can change with
time, but when one cell reaches 3630 mV the
BMS connects it with an electrical resistance to
allow other cells to reach 3580/3600 mV without
any overcharge. However, the lowest cell should
be at minimum 3450 mV.
When another cell reaches also 3630 mV, BMS
connects it to a resistance. At the end of the
equalization operation, the highest cell changes
after few seconds, because when the BMS con-
nects a cell to the resistance its voltage
decreases.
If a cell reaches 3630 mV and after many hours
under charge the highest cell is still the same,
without increase in the "average" value, there is a
failure because the BMS is not able to discharge
that specific cell. In this case it is seen that
• SOC never reaches 99-100%
• Delta (mV) is more than 250 mV
• Average voltage does not reach 3580/3600 mV
• Highest cell is the same
• After every charge of battery pack, final SOC
level is lower than the charge earlier
If above conditions are seen, it is necessary to
replace the BMS.
A new BMS will need more time to get equaliza-
tion of cells as the cells have different level of
charge. However, it is sufficient to leave the
machine under charge for at least 48 hours to
allow BMS to reach a good pack balance.
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SECTION 3 - TROUBLESHOOTING AND FAULT CODES
4. Average: It is the average of the total cell values
(Volt). At the end of the equalization phase, it
should be around 3580/3600 Volt.
The image below shows the details of voltage
values of all cells in 48V battery pack. The cells
voltage is read while the system is ON or during
charging or discharging.
MAF12270
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