Club Car batteries with corroded terminals, loose connections or damaged relay wiring may not charge fully. Dry batteries can also fail to charge, and are especially problematic in hot weather. Sometimes the problem lies with the battery charger, not the battery; for example, if the charger's transformer or circuit board is broken, it will not work properly.
Battery charger plug failure is a common problem with Club Car chargers. Signs of plug failure include bent or broken prongs, or melted plastic around the plug or receptacle. If power to the battery fails intermittently during charging, it is possible that plug failure is the cause. Broken plugs should be replaced because they can start fires if the leads inside get too hot.
Other common problems with chargers include diode and timer unit failure. Timer units keep Club Car batteries from being charged for too long; they automatically shut off the charger when the battery is optimally charged. A timer that fails to do this can cause the battery to overcharge. When a diode fails, the electrical current cannot pass through the battery. An external fuse may blow if this happens.
Poor battery maintenance is another common cause of battery charge failure. For example, if a drained battery is not immediately recharged, it can lose all of its voltage. In this case, it may not be possible to charge it again, because chargers require batteries to have some voltage in order to work. Recharge batteries immediately after use to avoid this problem. Additionally, if any parts of the electrical system, such as the car's lights, were left on during charging, the battery may not reach full charge.