Stihl MSA200c battery charging issue after inactivity.

[Fatboy2017]

I have a Stihl MSA200c  cordless chainsaw, was used 6 months ago and charged up fine no issues. Had a couple of jobs to do which required a cordless saw, battery showed no lights even though battery, a AP200, was left with approx 75% charge when put away. 

On connecting the charger (AL101) lights up solid green for 3 seconds or so then goes quickly to red, then al lights go out.

The Stihl service info I've read does not mention this code situation. Any ideas? New batteries are horrendous cost so trying to recover this one. I have many saws so not stuck for an alternative but find this one very useful for jobs it's designed for. @mark-skyland? 

[kram]

Assuming the battery has no warranty, batteries can usually be recovered. Lithium cells like to burn if not used properly so this takes some care. Do it in a fireproof, dry place.

 

AP200 is a 20 cell, 10 series 2 parallel battery, 10x 2.5Ah cells in series to get 36v, two rows of 10 in parallel to get 5Ah.

 

The first check is using a multimeter on the + and - tabs, what is the overall battery voltage?

 

Chargers usually refuse to charge cells that have dropped below about 1.5v.

With the battery opened up, the next check is how well it is balanced - check each pair and note it down.

 

If any are below 1.5v they need to be charged slow, at 100mA or so.

Buy a cheap RC charger - few go up to 10 cells so you will have to individually charge every pair, or you could charge 5 pairs at a time with balance leads.

 

Once its recovered it should charge normally on the stihl charger.

Edited 11 minutes ago by kram

[Fatboy2017]

Thanks for info.  I will try to take in what you suggested, electrics are not my thing but I'll have a go.