Likely a charging environment issue or a faulty battery/charger.
FIX:
- Check temperature: Do not charge outside the specified temperature range. Exposure above 40°C (104°F) can prevent proper charging.
- Check connections: Ensure the battery is fully seated on the charger and the charger is plugged into a matching outlet.
- Check the battery terminals: Keep them away from metal objects like paper clips or keys. Shorting the terminals can damage the battery.
IF THAT DIDN'T WORK: The battery may be damaged. Do not use a battery pack that is damaged or modified. Do not expose it to fire or excessive heat.
HEADS UP: Charge time is 1-2 hours. A red light indicates charging; green means fully charged. If the light stays red indefinitely in a normal-temperature environment, the battery or charger is likely defective. Service of battery packs should only be performed by the manufacturer or authorized providers. Do not attempt to repair it yourself.