I blew the battery in my stand alone hotspot because I kept it plugged into the charger.
The way it was explained to me is... When you use your tablet etc. it draws on the battery then the charger kicks in to top it up. This constant discharge/charge will over heat the battery and kill it. Better to discharge the battery fully then charge it up. You can use it while its charging but unplug soon as its topped up.
The battery was bloated to twice it's size. This is on the portable hotspot, not the tablet.
