dead dewalt battery

[chunkolini]

I bought a used DW circular saw and 5ah battery recently. Blade looked a bit dull but I had some chipboard top cut so figured give it a go. Not bright of me perhaps.
The battery had three lights indicating a full charge. Saw struggled so I stopped and the battery seems to have died,
No reaction from the charger, no lights at all.
then it gets odd. Press the button on the front of the battery and the three green led's just about flash for a fraction of a second
Any thoughts? An easy fix?
I'm wary of messing with lithium batteries; too many horror stories out there
im debating offering it for free on the for sale pages

 

[Parm]

Just buy a new battery, plenty of good aftermarket options which are cheaper than the original

 

[chunkolini]

thats already in hand

 

[JOEPRO]

There are a good few gaz tube (R) videos on Dewalt battery repairs. I'd say nothing to lose but watch a couple of them and pop the old battery open for a look see.

 

[Screwdriver]

There are really only three key issue with re-celling a tool battery pack.

1. can you pop open the case without breaking it
2. Can you source some DECENT (presumably 18650) battery replacements at a cost effective price
3. can you weld (spot or solder -yeah I know you shouldn't but I always do) the internal connections

A chap with your talents should have no problems given suitable equipment. I'd happily re-cell it for you but just posting it to and fro would be cost prohibitive and I'd have no way of testing it here either. So really you have nothing to lose by having a crack at it yourself.

 

[jsf55]

My Milwaukee 4 amp battery played up after extended use the other day, i had too cycle the charger a few times before it started charging, worth a try ?

 

[Wallace]

I have revived a few where the voltage has dropped too low and the charger will not start, just needs each cell bring up slightly to register and let the charger take over.

 

[lazybones51]

I had a Dewalt battery behave the same. Tried the "jump" trick and it worked. Got to be worth a try

 

[chunkolini]

well there you go.
Even electrophobe Chunko is willing to have a go at that.,

 

[chunkolini]

Gave it a quick go. Promising
the lights on the dead battery all light up when connected to the live one but no action on the charger after a few minutes. Had to leave base but will try again tomorrow
Exciting bit the wires shorted out as some dummy disconnected them, KRACK! and the ends near melted together. The lead from an old lamp got rather warm as well.
no way am I leaving this exercise to itself. 2nd go had the same reaction from the lights minus the short.
I will report back