Symptoms
- Light blinks rapidly instead of the normal charging pattern
- Light shows red, amber, or alternating colors
- Charging never reaches the solid 'done' indicator
- Different battery in the same charger charges normally
Likely causes
- CommonBattery pack is faulty or has a bad cellThis is the most common cause of a persistent error light that doesn't clear.
- CommonBattery too hot or too cold to begin charging safelyMany chargers pause and flash an error until the pack reaches a safe temperature range.
- PossibleBattery contacts dirty or not seated fully in the chargerPoor contact can be misread by the charger as a fault.
- PossibleCharger unit itself has failedAge, a power surge, or a damaged cord can cause a charger to misbehave with any battery.
- PossibleBattery deeply discharged for an extended periodSome chargers can't recover a pack that's been sitting at zero for a long time.
What to do
- Check your specific charger's manual or label for what each blink pattern/color actually means, since these vary by brand.
- Let a warm or cold battery reach room temperature, then retry.
- Reseat the battery firmly and wipe the contacts on both battery and charger with a dry cloth.
- Test a different battery in the same charger to see if the error follows the battery or stays with the charger.
- Test the questionable battery in a different, compatible charger if you have access to one.
- If the error is consistent on a specific battery across chargers, that battery has failed; if it happens on all batteries in one charger, the charger has failed.
Tools and parts
- Dry cloth
Replacement battery chargerSearch: “cordless drill battery charger replacement”
Replacement battery packSearch: “cordless drill replacement battery”
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.