Fully charged M18 XC 5.0 battery and NO power to tool

[Dantheman]

I have a problem different from anything I read on Google. I have a M18 XC 5.0 that I purchased about 2-1/2 years. I hadn’t needed it right away so it sat in my drawer for about a year. I took it out of the package and put it onto the charger and worked GREAT for about 6 months.  My problem is, the battery indicator light shows fully charged however, when I put it onto the tool, NOTHING, no power. (DEAD).  I put it back onto the charger and it says it’s fully charged (GREEN). I haven’t done anything with the battery since today (about 6 months later). I watched a lot of videos about testing volts so, I opened it up only to find out according to my multi meter and videos I watched, it’s fully charged and all the battery testing confirms there is nothing wrong with it. I thought it might be my charger however, I do have a second battery and it works flawlessly on the charger and on the same tool. If I take a positive and negative from that battery and run a test light, Lots of power. I put my multi meter over the other 3 connectors on the battery and it tests the same as the good battery fully charged. While I had the battery apart, I couldn’t see any corrosion or bent tabs where it connects to the tool. All batteries inside test at 4.00 to 4.02 and the main test at 20.04. I put back on the top cover and I get 20.04 however I can’t get power to my tool. Other battery works fine on my tool

[timc995]

I know this is an old thread, but thought I'd add my response for posterity.

 

I had this issue on an XC 12.0 battery.

 

It turned out to be a bad connection.  I had dropped the battery months before.  It worked fine, but then suddenly stopped.  As the OP describes, it read fine and 'looked' charged.  What had happened was one of the nickel strips had become un-welded from another (it was the main negative terminal in my case).  I'm sure it was weakened by the drop, and eventually became totally disconnected.  The strips were in contact with each other -- so connection was good enough for a voltage check, but it wouldn't pass enough amperage for the tool to work.  I added some solder between those strips, and everything's been working perfect since.