I have recently bought a 4gee mini wifi 2020 router it works fine but the battery doesn't last very long can you leave it plugged in whilst your using it
You can but that's what ruins the Battery over long periods of time.
Depending on the model some MiFi Routers will run ok with the battery removed, others won't, try it
You could also try Booting up the Router then after 5 mins remove the battery whilst plugged in and running, also your using the original USB Lead if not a decent modern one , same again for the USB Power Supply.
