[cbliss]

Chargers are not generally sealed and can take up quite a bit of bike space. You would probably not want to install a charger on the bike.

Kelly has an option for sealed but you are still going to need to protect the connections where they come out. Same with the batteries and motor.

 

[cbliss]

... Why would he not want to install one on board?

I am mostly involved with racing motorcycles and when you are trying to cram as much power and range into a bike, you need all the available space for batteries. My scooter has an external charger as do the eBikes I am familiar with. Just a matter of perspective I guess.