1) When a new wheel is first used, the spokes will naturally loosen a bit as they settle in and should be re-tensioned correctly to prevent them from becoming too loose. Some people apply thread locking compound when assembling wheels to prevent the nipples from working loose, but this will not prevent the spoke tension from decreasing as the spokes and nipples bed themselves in to the holes in the hub flange and the wheel rim.
If spokes are severely overtightened, they tend to snap or strip the threads inside the nipples, and I have never experienced nipples coming undone on correctly tensioned spokes.
I usually tension my spokes as tight as I can get them without without starting to round off the square drive on the nipple, and I have never had any nipples/spokes come loose after initially retightening them. It is important to make sure the spokes are all evenly tensioned and that the wheel rim remains concentric and true.
2) It is not good for the battery to use regen while the battery is fully charged as it could lead to overcharging of the battery if the controller or battery's
BMS is unable to prevent it.
My Vectrix electric scooter has very poor
(almost non existent) regen when I set off with a freshly charged battery and I have to use the hydraulic brakes to slow down gently at the end of my road, but after a mile or so I can stop reasonably quickly using just regen alone, and the Vectrix weighs 210kg
(462lbs) without the rider and pillion!
Regarding the wheel spinning faster when applying the brake with the wheel off the ground, does it do the same when the front or rear brake lever is pulled, or does it not make any difference?
(Assuming the brake switch operates before the mechanical brakes start to grab.)Alan