I got a Chargie device for my phone. I’m sorry but I can’t recommend it.
The promise is “Chargie is an app+hardware phone charge limiting solution that makes your battery last for much longer than if you had charged it regularly to 100% all night, every night.” It limits charging by unplugging the USB cord when your phone is charged enough.
Here’s the review I emailed to the developer and posted on Google Play. I’m sad that after a month, there’s been no response.
Two Stars out of Five: I got my Chargie April 2, 2020 for my Pixel 2. This review is on Jun 3. It’s a good idea, the app is well written and the device works (with a few tiny glitches) but I’m concerned that it won’t save my battery. Now instead of staying at 100% in the overnight, my battery goes between 80 and 85% charge several times per night. If it’s the act of discharging that is bad for a battery, then Chargie won’t solve the battery-wear problem. :-( I want it to work but I uninstalled it. Maybe it would help if it automatically turned on Battery Saving mode while on the Chargie device.