Need help with oddball fuse selection

It all boils down to Watts

Watt?

Aaaaand today the owner accidentally tore the throttle wire when the handlebar swung around backwards and she tried to straighten it the wrong way. I was careful to leave enough slack for the handlebar to face backwards, but not more than that. I didn't think the brake lines would allow any more rotation than that.

Almost lasted a week. Almost.

Update: Turned out the throttle cable wasn't the one that broke, it was a brake lever sensor cable, it would've been hard to fix because of where it broke but rigging it out of the way was a quick and easy fix, once the rider is careful not to ride the brakes.

Anyway, the owner's been using it almost uninterrupted but she's not happy with the range. I don't know what it's supposed to be in real-world usage. The trike is one of these:

http://www.electric-scooters-galore.com/iziptricruiser.html

I just got a call that it's cut out completely far from home, so I've told her not to charge it and that I'll look at it this evening. I'll have to take a close look at how she's using the old-school charger, she might not be giving it a full charge.