The BatteryCharge25 will show a red LED if a fault is detected with the unit.
The LED will flash the error code, pause for 2 seconds, then repeat for up to 30 seconds.
Touching one of the push buttons while the error LED is flashing will make the unit re-attempt battery charge immediately.
30 seconds after a fault is detected, the unit will automatically re-attempt battery charge. After 3 consecutive attempts the unit will remain in the error condition until power cycled, or you press one of the settings buttons.
The flashing of the red LED determines what type of fault is happening.
| Indicator | Fault Type |
| Solid red |
The battery is not taking a charge current. The fault type is unknown. |
| Single red flash |
Reverse polarity battery detected. |
| 2 red flashes |
Overtemperature. |
| 3 red flashes |
Output short-circuit detected, or current output is too high. |
| 4 red flashes |
Battery undervoltage detected, or output voltage is to low due to a hardware fault. |
| 5 red flashes |
Battery overvoltage detected, or output voltage is to high due to a hardware fault. |