Hope this is better! Thanks for bearing with me.
So the charging element definitely has three wires.
We agree that the max input of 2a is a bit irrelevant because of the USB charger inline bit (not the wall socket) should be able to handle any normal USB current?
View attachment 143638
that looks like the balance lead for the battery.
the battery pack looks to have two cells in series. so the charger has the 2x cell POS and one NEG.
Hence the 3x pins.
