Look at this page maybe there is some info you need here

https://supersocoforum.com/forum/super-soco-ts/range-and-regen-braking/#post-47

• I tried it and I saw the icon couple times but it didn’t charge the battery so it was really useless!

I experienced that too, so it's something differint. Maybe with a firmware update it's fixed but I will look at some Chinese sites if I can find something

The regen braking is very weak. You barely notice it, that’s why the battery percentage never goes up. 

I bet the regen is no more than 1-2 amps. What we need is something like 15amps, trouble is you run the risk of locking the rear wheel then, so thats probably why you can’t incease it.