Diagnosis: Bicycle battery charger not...

IS MY BATTERY CHARGER DEFECTIVE?

Is your bike battery refusing to charge, or not charging fully? The charger may be defective or malfunctioning. The following are possible causes:

1) Poor contact between the plug and the charging socket
This occurs when the charger’s tulip plug doesn’t connect properly to the bicycle battery’s charging socket. The charger light stays green or jumps from red back to green (with the slightest movement) before the battery is fully charged. The tulip plug is often stretched, causing it to easily lose contact with the battery’s charging socket.
→ Use pliers to deform the charger plug just enough so that it fits properly around the battery’s charging contact again.

2) The battery is charging, but not fully.
Sometimes the charger does charge, but only to, for example, 60 or 70% of its maximum capacity.
→ A fully charged (36 or 37V battery) measures approximately 42 volts between the terminals. If the charger stops and the battery only measures 36 volts, for example, the charger may not be working properly. The best way to test this is to connect another charger after your own charger has stopped charging.

3) The charger is defective
If the LED light does not illuminate when the charger is connected to the mains, this could indicate a defective charger. However, if this light does not turn red when the battery is (partially) empty, it could also indicate a defective charger.
→ It is best to have the charger checked by an expert.

The battery charger is defective or has a malfunction

1. The charger doesn’t work at all. The light on the charger doesn’t light up when connected to the mains, and the charger doesn’t heat up when connected to the battery. → The charger has probably failed and needs to be replaced.
2. The charger charges the battery, but not fully. The light on the charger turns red and the charger heats up, but the charging process stops before the bike battery is fully charged. The bike battery’s charge status indicates that the battery is not fully charged. → The charger is defective and must be replaced to charge the battery to 100% again.
3. The light doesn’t turn red, or it only turns red briefly and then green again. This could be a fault in the charger, but more likely, it’s the bike battery that’s no longer charging. → Check the battery first.

Besides the battery charger, the battery itself could also be the source of the problem. Click here for possible problems with bicycle batteries. If you have any doubts about the condition or functioning of your battery, you can also have it tested by RAP. Click here for more information.