Phone won’t charge until it dies.

Hi Randy,

That's a new one on me. Let's explore the battery charging for an iPhone and discuss what could go wrong.

Okay, the whole purpose here is to provide power for the phone to work. The battery does that by converting electricity into a chemical reaction to store the power, then the chemical reaction reverses to generate power. So we can see by the fact that it does charge and power the phone until it dies that this part is working.

The battery has two ways of getting charged in your phone, wired and wireless. So far we've only discussed one of those; you didn't specifically mention which, but the assumption is you're plugging it in to charge it rather than using a wireless charger. Those two methods use different circuitry to get electricity to the battery, so it would be interesting to find out if whichever one you aren't using is working the same way or not.

If it works correctly on the wireless charger but not the wired one, then we'd want to look at the lightning port connector that carries the power up to the motherboard where it then gets fed to the battery. If the wireless charger is not working but the lightning port does, then we'd focus on the wireless charging coil and its connector to the motherboard.

On the other hand, if they both behave the same, then what's left is the charging electronics on the motherboard which get fed to the charging circuitry built into the battery. If the problem lies on the motherboard, repairing it is possible but requires specialized microsoldering expertise and equipment. However, if the problem is in the battery's electronics, the the solution is fairly simple and consists of replacing the battery.

I'm not a repair technician, nor do I play one on TV, but I have taken apart a lot of iPhones and fixed them for family and friends, so if it was my phone here's what I'd do.

First, check the other charging method available and see if it behaves the same. That will narrow down what we need to fix.

If it behaves differently, come back and add that information to your question and we can proceed from there.

If charging wirelessly doesn't work any better than charging with a cord, then the simplest and most obvious repair is to replace the battery. You can, of course, take it to a repair shop and have them diagnose the issue and give you a quote for the repair, but to be honest the battery for your phone isn't too expensive and in my opinion would be worthwhile to replace as the first attempt at fixing this problem.

Should you get to this point, you can support iFixit's repair efforts buy buying your replacement battery from them; I'd recommend the Fix Kit version as it comes with all the tools and adhesives you need to do the job right for just an extra $5 USD. If, on the other hand, you want to save money, you can find replacement batteries on sites like eBay, Amazon and AliExpress. Be sure to also buy battery and display adhesives for putting everything back together again.

iPhone SE 2020 Battery: Replacement Part / Repair Kit

The battery replacement procedure itself is pretty standard for iPhones these days; remove the display, take off a metal retaining plate and unplug the battery. The battery is glued down to the case with that stretchy Command-style adhesive, so there are some parts that need to be removed in order to optimize the chance of getting those sticky strips out without breaking them. Once you've got the adhesives out, the battery comes right out. Pro tip: If you end up breaking a strip and having to pry the battery out, DO NOT use a metal tool to do so! I killed an iPhone X motherboard when the metal pry tool I was using tore the battery covering and sparked the case. Don't be me, lol.

iPhone SE 2020 Battery Replacement - iFixit Repair Guide

Hope this helps. Let us know what you find!