Firstly, I noticed that it discharges the battery fairly fast. It was easily 50% after a few months.
Secondly, when the battery goes very low (I haven't determined how low exactly) the battery/power LED starts to blink even when the machine is "turned off" ![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/facepalm.gif)
It appears that in this state, it discharges itself down to the hard protection in the battery itself, at 2.5V per cell. Job well done ![Roll Eyes ::)](https://www.eevblog.com/forum/Smileys/default/rolleyes.gif)
When I reconnected it yesterday, the battery didn't even want to charge initially, only started on the second or third try.
I have previously stored unpowered x86 laptops with batteries in them for months too and never seen similar problems.
- Li-Ion self discharge rate is very small. At the same time, Li-ion doesn't cope well with full charge. Some Li-Ion manufacturers specify in their datasheets to not store fully charged battery for long term. I've read some smart battery packs for drones will self discharge to about 50% if left 100% charged and unused for too long.
- there's nothing wrong if the LED blinks, the BMS (Battery Management System) will disconnect the battery completely when the voltage goes too low.
- when completely discharged, after the BMS cut out the power, you need to plug the charger and wait. Can take a few minutes until visible charging happens. At first the charging current is very gentle, so to not damage the battery. Plugging and unplugging doesn't help, while you plugged it 3 times, you just complete the time needed to wait. Plug once and let it be. It will start charging by itself, just not immediately.
- older laptops were not so careful with their batteries, but when you need to maximize battery life, like in a Chromebook, then you'll need to apply all the good practices, even when that will make users think you hate their batteries.
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)