Milwaukee tools are known for their performance and durability. But sometimes, you may run into an issue like the Milwaukee battery flashing red and green while charging. This usually means the battery has a problem. It could be due to temperature, a charging fault, or internal battery damage. In this article, you’ll learn exactly how to fix Milwaukee battery flashing red and green using clear and safe steps.
Whether you’re a DIYer or a professional tradesperson, this guide will help you restore your battery to working order quickly.
🔧 What Does It Mean When a Milwaukee Battery Flashes Red and Green?
When you place your Milwaukee battery on the charger and it flashes both red and green lights, it indicates a battery fault. Milwaukee chargers use color codes:
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Red Light – Charging.
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Green Light – Fully Charged.
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Red and Green Alternating – Battery Issue (possibly too hot, cold, or defective).
So, the flashing red and green lights don’t mean it’s charging; it means something’s wrong and needs your attention.
🛠️ How to Fix Milwaukee Battery Flashing Red and Green: Step-by-Step Guide
Step 1: Inspect the Battery for Visible Damage
Start by removing the battery from the charger and examining it for cracks, burns, or melted areas. If there’s any physical damage, do not attempt to repair it yourself. Damaged lithium-ion batteries can catch fire or explode. Instead, contact Milwaukee support.
Step 2: Check for Extreme Temperatures
Lithium-ion batteries are sensitive to temperature. If the battery is too hot or too cold, the charger will refuse to charge it. This often causes the flashing red and green lights.
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If the battery feels hot, let it cool down for 15–30 minutes in a shaded, room-temperature place.
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If it’s cold, bring it indoors and allow it to warm up slowly before charging again.
Step 3: Clean the Battery Contacts
Sometimes, dirt or corrosion on the contacts can prevent the battery from charging.
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Use a soft cloth or cotton swab and a bit of isopropyl alcohol to clean the terminals.
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Make sure the battery and charger contacts are dry before placing the battery back on the charger.
Step 4: Try Another Charger
The issue might not be with the battery. If you have access to a second Milwaukee charger, test the battery with it.
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If the second charger also flashes red and green, the battery likely has internal damage.
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If the battery charges normally, your original charger may be faulty.
Step 5: Perform a “Jump Start” with Another Battery (Advanced Users Only)
⚠️ Warning: This method involves electrical contact and should be done only if you’re confident in handling battery tools.
If your battery is deeply discharged, the charger might not detect it. Here’s how to “jump start” it using another fully charged Milwaukee battery:
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Take a fully charged Milwaukee battery of the same voltage.
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Use two small wires to briefly connect the positive terminal to positive and negative to negative.
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Hold the connection for 30 seconds.
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Remove the wires and try charging the battery again.
This often works to revive batteries that the charger refuses to recognize.
Step 6: Contact Milwaukee Warranty Support
If none of the above steps work and your battery is under warranty (usually 2–3 years), contact Milwaukee customer service. They often replace batteries showing flashing red and green lights if diagnosed as defective.
⚡ Common Reasons for Milwaukee Battery Flashing Red and Green
| Issue | Solution |
|---|---|
| Battery too hot/cold | Allow battery to reach room temperature |
| Dirty or corroded terminals | Clean with alcohol |
| Charger malfunction | Try another charger |
| Deep battery discharge | Attempt a manual jump start |
| Internal battery failure | Contact Milwaukee for replacement |
🧰 Maintenance Tips to Avoid Future Issues
To avoid the dreaded Milwaukee battery flashing red and green, follow these battery care practices:
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Store batteries between 50°F and 77°F.
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Never leave batteries in direct sunlight or cold vehicles.
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Charge batteries after every use.
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Use only original Milwaukee chargers.
🔋 When to Replace Your Milwaukee Battery
If your battery is older than three years, and none of the fixes solve the problem, it may be time to replace it. Repeated red and green flashes are often a sign that the internal cells are worn out.
You can check Milwaukee’s battery date code printed on the side to see how old it is.
✅ Final Thoughts
Dealing with the Milwaukee battery flashing red and green can be frustrating, especially during a busy project. But in most cases, it’s easy to fix with a little care and attention. Always start by checking temperature, cleaning contacts, and trying another charger. Only use jump-starting techniques if you’re experienced with battery tools.
If you’ve tried all methods and still face the same issue, Milwaukee’s warranty service is your next best option.
Now you know how to fix Milwaukee battery flashing red and green, so you can get back to work without delay.
