Chosen Solution
I recently purchased an Iphone 6 battery replacement from ifixit. I installed it and the battery was working fine until my phone started turning off and on once it hit the 20% mark. The reboots have started to occur more frequently at high battery levels i.e. 30%, 40%. Does anyone know the problem?
These symptoms are usually caused by a defective battery. While iFixit sells good quality batteries, it is possible that a bad one got through the cracks. I would contact them to see what they can do. However, before doing that, I would open up the device again and double check everything first. Use this guide. Does iTunes recognize your phone?
