I suggest you start by seeing if you smell burning from the hub.
If you do, then you are looking at replacement.
The next step is to put a voltmeter on the power lines, and see if there is a sudden drop in power when you press the throttle, that would indicate that the battery is damaged.
(It can charge to full, but drop under any load if a cell or two are bad.)
I always recommend a fuse in your power lines, it is very easy to overload these
things.
1000W/48V is just over 20 Amps. You can exceed this by riding up a hill or being a bit large like myself. (250+Lbs)
Good luck and keep us posted.