MacBook Pro (Retina, 13-inch, Mid 2014)

There is a good chance you have a bad battery. The quality of third party Lithium-ion Batteries is extremely poor even when purchased from a reputable vendor such as OWC or iFixIt. You've pretty much proven this by showing the old battery works.

bevmick69 wrote:

Just replaced battery in my MacBook Pro 2.6 GHZ dual core intel core i5 Retina with Battery A1582 A1493 for Apple MacBook Pro Retina 13”A1502 [2013 2014 2015 Years] plugged into charger battery not charging. Battery shows 43% but when charger is unplugged my Mac shuts down instantly.Pressing the power on button with charger unplugged no response,as soon as charger is plugged in and power button is pressed Mac turns on. Had charger plugged in for 6 hours but battery charge still at 43%.On drop down box below battery icon it states battery not charging. Have taken new battery back out and replaced with old battery and when power button is pressed Mac starts up as normal.I have contacted the seller and they claim that it is the correct battery for my model? The reason for changing original battery is that it has now done 1270 cycles and is now 8 years old and not holding charge 3 hours max from fully charged.Any ideas would be greatly appreciated.Cheers.

Try resetting the SMC http://support.apple.com/kb/ht3964

The SMC has to be "trained" to understand where the empty point and full point of this new battery actually are.

That can quickly improve with an overnight charge, and will get even better after a few regular cycles -- no special rituals are required or helpful.

charge overnight.

Use it normally.

Done.

a modest variation on that:

Charge overnight.

Reset SMC.

Use normally.

Done.