There is a lot of variables involved to muddy the waters, if I'm fighting a 30 - 40mph head wind on the way into work the battery will be way under 50%, also due to the nature of the terrain for the homebound journey the roads up in the hills often get closed due to landslides, snow, flooding etc so the 14 mile journey can easily become 30 mile so riding 30Kg of dead ebike 800 feet up a pitch dark alpine road kind of looses some of the magic.
I definitely wouldn't leave a lithium battery on an unattended charge without a timer no no no.
I definitely wouldn't leave a lithium battery on an unattended charge without a timer no no no.