So I dismantled the three junk packs I got from halfway around the world and rebuilt them with better-quality cells. Search for NP-FS11 and you’ll find the rest of the story.
These cases are the thinnest plastic that doesn’t actually break when you pick it up: to crack the case seam, you must push firmly. Two of the three packs were already cracked and the third yielded to a slight squeeze.
What’s inside? Welly, welly, welly, what do we have here?
The cells are labeled Sony Energytec, which ought to be a reputable brand name. Some possibilities:
- Counterfeit cells
- Quality test rejects
I don’t know why you’d bother putting counterfeit cells inside a generic case; it’d be more profitable to sell a completely counterfeit battery with a fancy Sony label. So I’m guessing these came from a batch of cells that failed inspection and were miraculously saved from destruction.
They have the usual protection circuit board on the top. What’s a bit tricky is that you must unsolder the three leads connecting to the case terminals before you can extract the cells. I unsoldered the strap from the negative terminal while I was at it; the positive lead is inaccessible beyond the black IC on the left.
After that, it’s a straightforward rebuild.