Chosen Solution
My sister’s phone drains while charging. It will usually go up to 31%, but then later it goes down. I find nothing wrong with phone, charger, or outlet. I can’t seem to find the solution to fix this. I have tried everything from cleaning the phone to restarting the phone a couple times.
Not an easy solution here, as it might be a bad charger, which should be easy to rule out wit any other charger you have around with a Usb port.. or a bad battery, if the replacement charger doesn’t fix the issue. Replacing battery is a bit more troublesome, but it can be done, have a look at the guide. Last possible reason would be the charging circuit, but that’s not a DIY job, you’d need to find a Pro for that. Samsung Galaxy S9 Battery Replacement
