Review (2/5): The battery is not high quality
6 months of use and my battery is no longer functional. The manual suggests not keeping the unit plugged in for more than 12 hours -- this suggests to me that the battery is susceptible to being ruined if plugged in for too long... which makes it one step more difficult to keep in good condition.
Though, after less than six months owning this shaver, it doesn't even turn on anymore. I've been unhappy throughout the life of the product though - battery life has been a constant issue. Not being able to shave my entire head without the battery dying!