"sms" wrote in message
news
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon. These lights don't have user-replaceable
batteries, but by removing two screws I was able to open it, and the
battery pack does have a connector on it so at least they didn't solder it
directly to the printed circuit board.

It's a 2 cell 18650 pack with the batteries in parallel, and a protection
circuit board shared between the two cells. The cells are allegedly
2800mAH, for a total of 5600mAH. The closest I could find on-line was a
2x2600mAH parallel pack https://www.amazon.com/dp/product/B003SH4BV6.

I moved the connector from the old pack to the new pack, plugged it in,
and closed it up. Seems to work fine now.

My favourite is recycle bin rescues - with a £0 price tag; life expectancy
isn't something to get traumatised about.

Most laptop packs are 2 or 3P-3S, you can split them up as series or
parallel pairs A/R.