Less than a penny a mile on mine including replacing the batteries at 3/4 of there life expectancy.
It's easy to work out, your leccy bill has the unit price on it
(Or generate your own juice
)
There isn't really a service interval, just keep an eye on brakes/tires/bulbs/bearings.
Some things to watch out for:
Some manufacturers quote absolute range (until the bike creaks to a halt)
others quote useable mileage (until the performance starts to drop off or it will no longer hit a certain speed)
That makes it tricky to compare
Battery chemistry makes a big difference.
Lithium batteries are lighter and more powerful but expensive and don't last (and less green)
Silicon batteries are heavier and less powerful but cheaper and last longer. They also stand up to abuse better and are sourced/recycled in a friendlier way.
I would always go for something with excess range
I needed to do 20 miles so I went for a 40 mile range. That way I knew I could make a detour, or I could unplug it Nd nip to the shops without worrying. I could also still get to work in the morning and charge up there if there was a power cut or something. Sometimes i'd get home and have to straight back out again so that extra juice came in handy.
They use intelligent chargers. They manage each cell for you and switch off
"Charge time = 6 hrs" or whatever is a bit misleading. Usually you are only topping up. Most of the time mine took 1-2 hrs - and that is on very outdated tech.
Regenerative braking extends your range, definately worth having - and it gives you a free reverse gear
There isn't much to go wrong - the most complex bit is the controller (a pcb, chip and regulator in a heat sink box). Easy and cheap to replace
