Any opinion about if fully dischargethe battery or not?
Thanks
Do you mean for the first use? Personally, I would. My approach is to do a series of little journeys early in the battery's lifetime to work your way down to 10-20% charge (small distances means that if you get down to nothing, you don't have far to pedal back home). Then charge it back up again fully. You can do that a couple of times if you wish, but once always seems fine to me.
From then, decide if you will charge after every use (longer journeys necessitate it) or every few uses (very short journeys can be combined into one charge, thus reducing the number of charge/discharge cycles).
So while I use my Ave XH-3 (a Bosch central crank MTB) every day, I expect it gets 250 charges per annum rather than 350 - thus extending the warrantied life of the battery. Well, in theory anyway - never had to put the warranty to the test!
Bear in mind that your battery management system (BMS) should prevent you from completely exhausting the battery's charge - it will cut out before the battery is so dead you can no longer charge it.