Battery placed on charger for the vacuum remains on solid red for an unusually long time and never turns green.

Safety first: Only use Milwaukee-approved chargers and batteries.

• 1. Time the charge: Most M18 packs should charge within 30–90 minutes depending on capacity. If it exceeds 2–3 hours, remove the pack.
• 2. Test on tool: Install the battery in the vacuum and check runtime. If runtime is very short, the pack is near end of life.
• 3. Try another charger: If available, charge the same pack on a different Milwaukee charger to see if behavior changes.
• 4. Compare with another pack: Charge a different M18 battery on the same charger. If all packs behave normally except one, replace that battery.
• 5. Replace failing component: If multiple batteries never reach green on this charger, replace the charger. If only one battery is affected, replace that battery.