Rapid Battery Drain Tristar Replacement

Hi.

I have a iPhone 6 here that is rapidly draining it’s battery in stand by.

100% to 0 with in an hour and a half. All batteries that have been fitted have done this. (Have tested a battery in another phone and it was all good)

I have replaced the Tristar pulling approx 1.2A on charging however the battery drain is still happening a lot slower though. Now it’s taking 8 hours but still no good.

I have replace the WiFi Cap 8 months ago as it was shorted.

Possible Tri star IC no good from new?

Or should I remove re ball and try again?

Thanks