Chosen Solution
Went on eBay and bought a new battery for my da’s iPhone 5 which had abysmal battery life - found out the battery has never been replaced and had over 1200 cycles! Installed it fine, everything’s snug, and it came up with the battery low screen when trying to turn it on. Plugged it in and left it for 5 minutes when it booted into the Apple logo screen. Now, it’s cycling between the low battery charging screen and the Apple logo. Any suggestions?
First thing that comes to mind is a faulty battery. Try plugging back your old one for confirmation that the iPhone by itself is still capable of charging. New batteries should come to buyer with about 70/80% charge, not drained. For future I would suggest to avoid the random eBay seller for battery purchase, better to increase budget a bit and buy from reputable vendors.
