| Fault phenomenon | Fault check and cause | The solution |
| Unable to charge | Measuring the voltage of 4 groups of batteries. | Pair the battery pack well, do not mix |
| when one of the battery voltages exceeds 4.25V, | the good battery and the bad battery. |
| the protection board will activate overcharge protection. | |
| Unable to discharge | Measuring the voltage of 4 groups of batteries. | Pair the battery pack well, do not mix |
| when one of the battery voltages is lower than 2.7V, | the good battery and the bad battery. |
| the protection board will activate the over-discharge | |
| protection. | |
| Charging/discharging | OV, 4.2V, S.4V, 12.6V, 16.8V miswired | Rewire or replace the new board |
| failure | (human failure, no warranty) |
| Overcharge/overdischarge | OV, 4.2V, 8.4V, 12.6V, 16.8V miswired | Rewire or replace the new board |
| failure | (human failure, no warranty) |
| Discharge protection | Check that the battery pack has sufficient discharge | Replace the battery pack with a higher |
| capability and check that the load's starting current | discharge capacity, or a protective |
| exceeds the overcurrent protection current of the | plate with a larger current |
| protection board. | (super working range) |
| Component soldering | There is no connection between one of the components | Repair welding |
| and the PCB pad. |
| Component welding | There is a short circuit between two or more pins of the | Remove the component and re-weld |
| component. |
| Electrostatic breakdown A | In the unpowered state, measure the G, D, and S | Remove the replacement MOS tube |
| poles of the MOSFET. If the forward and reverse |
| resistances of any two pins are 0Q, |
| it indicates that it has broken down. |
| Electrostatic breakdown B | Remove the MOS tube and measure the resistance | Remove the replacement MOS tube |
| of the G and D, G and S poles of the MOS tube. |
| If there is a resistance indicating that it has broken |
| down, the resistance should be infinite. |