Milwaukee 9.0ah battery not charging

[Jason280]

I have a Milwaukee 18v 9.0ah battery that will no longer take charge. It was showing one bar on the charge indicator, but no matter which charger I tried, would always show green when placed on a charger. Now its to the point the bar is flashing red (meaning the battery is essentially dead), and still only shows green on a charger.

Is this likely a dead cell and no chance it will charge, or something else? Anything else to try to get it to charge? Not sure if its still under warranty, may need to check tomorrow with Milwaukee.

 

[Jsf721]

I have had luck reviving them with the older HD chargers. Newer ones require too much voltage to be seen

 

[allinon72]

When this happens to me and I can't revive it by jumping it with another battery, I just go ahead and send it in.

 

[Jason280]

I have had luck reviving them with the older HD chargers. Newer ones require too much voltage to be seen

Not sure if I have one of the older style chargers or not, how are they different?

 

[Jason280]

When this happens to me and I can't revive it by jumping it with another battery, I just go ahead and send it in.

Jumping with another battery??

 

[allinon72]

Jumping with another battery??

Yes, positive to positive negative to negative.

 

[Sumboodie]

When this happens to me and I can't revive it by jumping it with another battery, I just go ahead and send it in.

They fix?

They are HAZMAT so can't easily ship them.

 

[Jsf721]

Not sure if I have one of the older style chargers or not, how are they different?

Just worked better for me. No surprise the older ones are better.

 

[Jason280]

Yes, positive to positive negative to negative.

I may need some more details here. How long are you jumping them for? Are you simply jumping them, together for a period of time, and then throwing it on a charger?

 

[allinon72]

They fix?

They are HAZMAT so can't easily ship them.

If under warranty, they have you print out all the necessary warning labels that need to be on the outside of the box. It’s easy.

 

[allinon72]

I may need some more details here. How long are you jumping them for? Are you simply jumping them, together for a period of time, and then throwing it on a charger?

30-60 seconds, just enough to give the cells a jolt so the charger recognizes the battery.

 

[GaryM909]

I have a Dewalt 9 ah battery that wouldn't charge about a month ago. After I kept trying for a couple weeks I put it in my leaf blower and ran it until it was fully drained. I then put it back in the charger and it charged right up.

 

[dnschmidt]

This is at least a 5 year old battery and 1) is no longer made 2) is out of warrantee (3 years). Secondly, this was a notoriously bad battery, true not as bad at the old 12.0 or 8.0, but the fact is it's time to go to the Home Depot and throw it into the battery recycling bin.

 

[Beerhippie]

Oddly, I was in the process of salvaging the good cells from some old Mildew batteries I retired a few years back as they'd no longer take a charge. I kept finding the most, and sometimes all, of the cells tested out and charged just fine by themselves and stuck a couple of the old battery packs into the red charger... they're now back in rotation!

I haven't seen any YouTube vids about letting dead batteries sit around for few years to revive them....

 

[Jason280]

Tried jumping it with another battery, no luck. It would actually read a charge, but quickly die off when actually using...either way, not matter which charger I tried, it still lights on "green" (charged).

 

[Rinspeed]

30-60 seconds, just enough to give the cells a jolt so the charger recognizes the battery.

Wear safety glasses just in case.

 

[tak1313]

Tried jumping it with another battery, no luck. It would actually read a charge, but quickly die off when actually using...either way, not matter which charger I tried, it still lights on "green" (charged).

It may be one (or more) individual cell(s) are marginal/bad and causing the logic circuit in the battery/charger to see a high resistance and think the whole pack is charged. The high resistance would make the charger think everything is all charged up when it's not. It could also be a bad resistor or capacitor in the circuit (of the battery).

 

[cgrutt]

Probably a bad cell you can open it up and measure voltages individually. Bad cell will probably show some signs such as swelling, etc. in addition to having lower (or no) charge. I have a few packs I've been meaning to open up and replace cells. I'm planning to replace all of the cells not just the bad ones. I ordered the replacement cells online they were fairly inexpensive and are same type used by Milwaukee. The cells in my pack were made by Samsung not sure if that changes or not.