My cordless drill battery won't charge - flashing light on charger?

Hey everyone, having a weird issue with my 20V DeWalt drill. The battery won't charge - when I put it on the charger, the light just blinks red continuously. Tried cleaning the contacts with alcohol, no luck. Battery is about 2 years old. Anyone seen this before? Is the battery toast or could it be the charger?

Carl, that flashing red usually means the charger detects a fault - could be overheat protection or a bad cell. First, let the battery cool completely if you've been using it. If it still blinks, try another known-good battery on that charger to rule out the charger itself. If charger works with other batteries, your battery's probably done. DeWalt batteries have protection circuits that fail sometimes. Pro tip: mark your batteries with purchase dates so you know their age.

my boss had this happen last month! same thing with his milwaukee. we tried the freezer trick - wrapped the battery in a towel and put it in freezer for like an hour? then it charged but only held half power. ended up recycling it. maybe try that as a last resort before buying new?

Don't put batteries in the freezer - that can damage cells and is a safety risk. Modern Li-ion batteries have specific temp ranges. Carl468, what's the model number on your charger? Some DeWalt chargers have reset procedures. Also, check if the battery terminals are slightly bent - sometimes they don't make proper contact.

Thanks Pete! Charger is DCB115. Tried my other battery and it charges fine, so must be the battery. Terminals look straight. Guess I'm shopping for a new one. Appreciate the help everyone - and I'll skip the freezer idea Carl632, sounds sketchy lol.