The Age of Enlightenment

A while back I bought a little battery powered work light from the House of Bezos. It wasn't half bad, but at the same time wasn't really half good either. One of the problems is that it just didn't last all that long on a charge; and while I'm sure the efficiency of the LED driver circuitry probably left a little to be desired, the big problem was that there was just a lot of empty space inside the chassis that wasn't filled with batteries, since it was only equipped with a 1S2P pack from the factory.

But fortunately for us, larger battery packs are not entirely all that expensive.

While I could have fit a 1S6P battery pack into the case, it would have been a bit of a squeeze and, to be quite honest, it's pretty hard to find them prebuilt in a 2x3 arrangement, and it's a bit of a pain to have to buy a spot welder to weld one together myself. So I settled for 1S4P instead, which cost me all of $10 or so from AliExpress.

Now I was fully expecting this pack to be composed of one real cell and 3 wooden slugs, but the weight of the pack almost exactly matches what I would expect from 4 real cells, comparing it with the old pack (which I had deskinned somewhere along the way while I was experimenting with some stuff). So chances are there's actually 4 real 18650 cells in there. They're probably still of questionable quality, but whatever, it's just a work light.

Anyway, the new battery pack has a nice JST connector on its leads, so I grabbed a pack of JST pigtails to plug it into, as the original battery pack was just soldered directly to the board.

And of course it's backwards. Well, luckily it's not that hard to depin the connector and reverse it to match up properly.

Putting the new pack on the bench supply showed it charging up with a reasonable curve, so everything was looking pretty good.

So now we just have to put everything back together again, starting with soldering the JST pigtail to the board.

And it looks like I managed to solder it correctly, so that's good.

Then we secure the battery inside the case. A little hot snot will do the job just fine.

You can see here how there would technically be room to squeeze another row of cells in there. But it might get a little crowded and I would potentially have to extend some of the leads a little bit.

And finally, we bolt everything back together.

Let's hope this battery pack works better than the last one.