Teardown: Keeppower P1835J Protected 18650 Flat top - different PCB to the button top!

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Big_Sam
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Teardown: Keeppower P1835J Protected 18650 Flat top - different PCB to the button top!

Hi folks,

I picked up this Keeppower 1835J flattop for use in torches that can’t take the longer button top version. I thought it would be the same as the button top version but it is not! The PCB on this version only has two MOSFETs! There is no way of finding out which PCB it has as they both share the same part number! The controller and associated parts seem to be the same as the three MOSFET version, so perhaps they are just pushing these MOSFETs harder than the three version? I would suspect it would have a greater voltage drop with just the two MOSFETs.

The PCB is mounted in a plastic tray on the – end of the cell, there is a cardboard washer insulating from the PCB. The + strip runs from the top where it is spot welded onto the burst disc under the top, not sure I particularly like that.

The cell is a Sanyo NCR18650GA as far as I can tell. There is no wrap, so no date code is present.

The mark on the gold board is just from testing in torches.