That won't directly fit his charger though - he'll need to use his JST-XH balance board with that stuck in it - too many connections that could skew the fine voltage readings for my liking. Maybe I'm just fussy though.
To answer a question in the original post that I've only just noticed, the charger will cut off when it (the pack) gets to ~4.2V per cell - it will fluctuate slightly - you're fine leaving it be.
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