It takes me 4h40 minutes to charge it up from flat. I also have trouble estimating how much charge is left after short ride as the indicator is not accurate (I am guessing as with all bateries the higher temperature of battery show up more range/power left but once left to cool down it shows the real amount). I once did 16 miles and pluged it for about one hour hopping to top it up enough to get mine 28 miles but i only made 27 miles before the motor switched off (i was still going with decent speed when it stoped – some kind safety cut off ?). i ride top speed all the time and often with lights on. I was wondering about the charging process. Is it slowing down towards the end like it does with mobile phone batteries? so lets say last 20 % takes the longer to charge up?