Tower cordless vac, needs battery and may not work anyway (Reepham NR10)

This is a Tower VL100 Optimum cordless vacuum cleaner that I believe is factory-refurbished. It’s certainly nice and clean. It comes with a powered fluffy roller for hard floors, and a stand. It’s not a fancy machine (retail price about £130) but it has a dust sensor, automatic power adjustment and so on.

There’s a massive snag: it doesn’t work. I’m reasonably sure this is because the battery (see photo) has failed. The problem is that (a) replacement batteries are hard to find, and (b) without a working battery I can’t be absolutely sure that the problem doesn’t lie with the machine itself.

So perhaps the best use of this is for someone who already has this model, maybe in a battered state, and would like a new one to use with their existing battery.

A note to potential repairers: this is not just failed cells. It’s one of those complicated batteries with its own MCU and probably a serial link to the machine itself. The cells seem fine but I’m pretty sure the BMS was broken straight out of the box. The main switching MOSFET is intact and nothing else has obviously exploded or shorted. You’re welcome to the bits (including the cells: 8 × 18650) if you want to try to fix it.