iPad Air 3 Battery charging

Hi Steven,

The battery's negative and positive connections are distinctive from the other three signal lines, so it's easy to figure out which is which. Here's what the schematics show for the battery connector.

Now if we look at the physical connector for the battery itself on the motherboard, we'll see five pins.

Going by the schematics, we're going to make an educated assumption that the pins on the physical connector are in the same order as that shown on the schematics. This is backed up by the fact that the three outer connectors - two on the left and one on the right - are very skinny, indicating they are signal paths and not power paths. Pins 3 and 4 are really fat, saying that they carry power.

So, from left to right, we have the following signals.

1. HDQ
2. THERM
3. PACK_NEG
4. PACK_POS
5. SENSE

So battery negative is the middle pin and battery positive is the one to the right of it. Double-check the polarity of the two pins on the battery with a voltmeter.

BTW, be vewy vewy caweful charging a lithium battery. Done wrong, they can literally explode. Not kidding here, dude; ask the owner of a Galaxy Note 7.