Saws

Cordless saw battery won't charge

A battery that won't take a charge is most often deeply discharged, has dirty contacts, or the charger itself has failed, rather than the saw being at fault.

Difficulty
Easy
Time
10–20 minutes
DIY cost
$30–$90

Symptoms

  • Charger light doesn't come on or stays red/blinking
  • Battery shows no charge after hours on the charger
  • Battery gets warm but doesn't seem to charge
  • Saw runs briefly then dies immediately

Likely causes

  • CommonBattery contacts dirty or corrodedPoor contact between battery and charger prevents current flow.
  • CommonBattery deeply discharged and needs a slow recovery chargeSome chargers need extra time to safely bring back a very low battery.
  • PossibleCharger itself has failedA dead charger can look like a battery problem.
  • PossibleBattery has reached end of lifeLithium-ion batteries lose capacity permanently after enough charge cycles.
  • PossibleOutlet or extension cord not delivering power to the chargerA dead outlet can be mistaken for a charger or battery fault.

What to do

  1. Test the outlet with another device to confirm it's supplying power.
  2. Clean the battery's metal contacts and the charger's contacts with a dry cloth or contact cleaner.
  3. Leave the battery on the charger for a full charge cycle, since some chargers take longer to recover a very low battery.
  4. Try a different, known-good battery on the same charger to see if the charger lights up and charges normally.
  5. Try the questionable battery on a different charger if available, to isolate whether it's the battery or charger at fault.
  6. If the battery won't hold any charge after a full cycle on a working charger, it likely needs replacement.

Tools and parts

  • Contact cleaner or dry cloth
  • Known-good battery or charger for testing
Replacement battery packSearch: “cordless saw battery replacement pack”
Replacement chargerSearch: “cordless tool battery charger replacement”

When to call a pro

If neither a different battery nor a different charger works, the saw's charging system or the batteries themselves should be evaluated by a repair shop.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.