I kinda like the Fakita battery system (Fake Makita) as it is a useful battery pack with built in protection against over-charge, over-discharge and overcurrent.

This kit comes without cells and is supposed to make a monster 30 cell battery with five series sets of six-paralleled cells, giving the potential for a 14.4Ah pack if using 2.4Ah cells.
(The Ah capacity is at the rated voltage and not all the combined cells, so it's just six times 2.4Ah.)

Unfortunately, the control PCB that was supplied is incompatible with the mountings on the battery frame. It might be viable to bodge it in somehow, but it's not recommended. Even with one of the smaller modules rated for lower load current, you would need to glue the PCB into place and have fly wires onto the battery block.

The control PCB is interesting as it uses the same control chip as the smaller modules, but has extra buffering to drive a large parallel array of load control MOSFETs. The gratuitous application of very stubborn silicone made it frustratingly difficult to do a proper full reverse engineering of this pack. I did find some things that made me prefer the smaller PCBs if the high current switching isn't needed.

Depending on what you wanted to do with it, the kit could still be viable for the cell assembly, so if you want to explore one then here's an affiliate link to the AliExpress listing:-
https://s.click.aliexpress.com/e/_c3b7JvTP
Interestingly, the control PCB shown in the listing is similar, but different to the one I received.



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