That blinking red light has a meaning. Every charger pattern, every fault code, every chuck and blade quirk — mapped to the actual model in your hand, by the people who've already taken the tool apart.
Independent · reader-supported · honest fixes. Some guides use affiliate links; we only recommend gear that genuinely works.
If your DeWalt DCB115 or DCB118 charger shows absolutely no LED light when a 20V MAX or FLEXVOLT battery is inserted, it usually indicates a faulty battery pack. Here is how to test and verify the fix.
Cross-brand troubleshooting, platform-aware. Find the manual that matches the battery in your hand.
Most "battery dead" calls aren't dead cells. Once you know which part of the pack is which, you stop guessing.
Squeeze to release. Worn springs cause pack drop-out under recoil.
Power + comm to the tool. Clean with a pencil eraser — never sandpaper.
4 dots, ~25% per dot. Hold the button for 2s to read state of charge.
5 cells in series. 18.0 V nominal, 20 V peak. The "20V MAX" you see in the catalog.
Cuts at 2.5 V/cell. "Pack dead" usually means the BMS locked out, not that the cells are gone.
Kills charging above ~70 °C. Hot pack? Wait 30 min — don't force the charger.
Jump straight into the issues tradespeople and DIYers run into most — battery faults, chuck problems, blade wobble, and OPE starting issues.