A few months ago I purchased an ifixit battery for my husbands phone. The exchange went very well and he was up and running in no time with a phone that held a full charge.
Then along comes my Mom's phone needing a new battery. A replacement was purchased from another company ( not by me) and when I took the old battery out of the iPhone 6S the old battery went up in smoke.
I put the new battery in and nothing happened, it would not take a charge... Well I thought I had toasted the phone but thought I would give it one more last ditch effort...
Here's why.... the phone was completely detached front from back. The battery was run down to zero when the smoke and sparks came out of it. So I looked at the phone and there was nothing that could have been affected by the above mentioned battery meltdown. I purchased an ifixit battery.. upon receiving it I put it in the phone and I'll be jiggered --- it came up to a full charge and is working like a charm.
Bought a static matt to do the work on... love the magnetic screws.... when you send the batteries please include the new adhesive strips even though the repair tools are not purchased.... I already had the tools from the last phone but was surprised not to receive strips...
Don't buy batteries from any body else but ifixit.... also download the Battery Care app and it will tell you what the health of your battery is. Each battery is just like a battery that you put in a camera or flashlight... they are programed to last for just so many recharges. Let them run down before you recharge them...