How Do You Fix a Milwaukee Battery That Won't Charge — Charging Fix

Quick answer

• Ensure the battery is warm enough to charge; lithium-ion batteries refuse to charge below ~32°F (0°C).
• Check for a defective battery by using a different charger or testing another battery in the same charger.
• Inspect the charger for faults; a red fast blink on a DeWalt DCB115 charger indicates a pack fault.
• If the battery is swollen or damaged, do not attempt to charge it; recycle it properly.

Symptoms

When a Milwaukee battery won't charge, you may notice the following symptoms:

• LED Patterns: The charger LED may show a steady red light, indicating charging, or a blinking red light, suggesting the battery is too hot or cold. If the LED alternates between red and green, this indicates a defective battery pack.
• Sounds: You may hear no sound at all from the charger, or a faint clicking sound when the battery is inserted, which could indicate a fault.
• Behavior Under Load: If the battery is inserted into a tool and the tool fails to operate, this is a sign that the battery may not be holding a charge.

Quick checks

Before proceeding with deep troubleshooting, verify the following:

1. Temperature: Ensure the battery is at room temperature. If it’s cold, warm it to at least 32°F (0°C) before attempting to charge.
2. Charger Functionality: Test the charger with a different, known-good battery. If it charges the other battery, the issue may be with the original battery.
3. Battery Condition: Inspect the battery for physical damage, such as swelling or corrosion. If any damage is noted, do not use the battery.
4. Charger LED: Check the LED indicator on the charger. Refer to the specific model's LED fault patterns to identify potential issues.
5. Connection: Ensure the battery contacts are clean and free of debris. Dirty contacts can prevent proper charging.

Step-by-step fix

1. Remove the Battery: Always start by removing the battery from the tool to prevent any accidental activation.
2. Inspect the Charger: Check the charger’s LED indicator. For example, the Milwaukee M18 charger shows a steady red light when charging and a green light when fully charged. If it’s blinking red, it may be too hot or cold.
3. Warm the Battery: If the battery is cold, place it in a warm environment for at least 30 minutes. This allows the battery management system (BMS) to reset and may enable charging.
4. Test with Another Charger: If available, try charging the battery with a different Milwaukee M18 charger. If it charges, the original charger may be defective.
5. Check Battery Contacts: Clean the battery contacts with a dry cloth to ensure a good connection. Corroded contacts can prevent charging.
6. Replace the Battery: If the battery still won’t charge and shows signs of damage (swelling, corrosion), it’s best to replace it. Consider upgrading to a Milwaukee M18 REDLITHIUM XC 5.0Ah Battery (48-11-1850) for improved performance.

View Milwaukee M18 REDLITHIUM XC 5.0Ah Battery (48-11-1850) on Amazon (paid link)
View Milwaukee M18 REDLITHIUM XC 5.0Ah Battery (48-11-1850) on Home Depot (paid link)

If it still isn't working

If the battery still does not charge after following these steps, consider the following escalation options:

• Warranty Service: Check if your battery is still under warranty. Milwaukee offers a 3-year warranty on M18 batteries. Contact Milwaukee customer service for warranty claims.
• Service Center: If the battery is out of warranty, take it to an authorized Milwaukee service center for further diagnosis and potential repair.
• Replacement: If the battery is confirmed defective and not under warranty, purchasing a new battery may be the best option.

FAQ

Why won't my Milwaukee battery charge?
There could be several reasons: the battery may be too cold, the charger may be defective, or the battery itself may be damaged.

What does it mean if the charger is blinking red?
A blinking red light typically indicates that the battery is too hot or cold for charging. If it continues to blink after warming the battery, it may indicate a fault.

Can I use a different brand charger for my Milwaukee battery?
No, using a charger from a different brand can damage the battery and void any warranty. Always use Milwaukee chargers with Milwaukee batteries.

How can I tell if my battery is defective?
Look for physical signs of damage, such as swelling or corrosion, and test the battery in a different charger. If it still doesn’t charge, it’s likely defective.

What should I do with a damaged battery?
Do not attempt to use or charge a damaged battery. Recycle it properly at designated drop-off locations like Home Depot or Lowe's.