Review on High-Performance Replacement Battery For Lenovo ThinkPad X230I And X220 Laptops - 6 Cell Li-Ion 4400MAh Capacity by Jayshawn Webb

I purchased this in March, 2020. It tested out fine at the time, and then I put it in my laptop bag, waiting for my aging Lenovo battery to give up the ghost. More than a year later, that battery is still doing OK-ish, but I decided to check the status of this DTK battery.Dead.Well, not all the way dead, but shortly after hitting the power button, the laptop flashed "Critical battery level" and shut down. I've had batteries be outside of a laptop for many months with only minor discharge, so this was surprising. It particularly bugs me because I know that it's harmful to a lithium ion battery to discharge it all the way. I would've used it every few months if I had known that it would self-discharge that quickly.