Yes i added a second battery connected in parallel with the stock one, i placed the connections in the bottom below the battery tray, so controller has m6 eyes, bolted the original cable and the new cable for the second battery in parallel on these connections, the second battery has a maxi fuse holder which i placed on top of the battery lock, holds a 50 amp fuse.
When you do this setup make sure you independant charge both batteries to full, if one is not full it will draw a very high current from the full one, after charging you can leave them both connected and use the charging connector on the bike.
Also a very big plus is the regeneration function, i have set these at 10 procent on release throttle, and 45 procent when applying a brake signal. Works really well, so the front brake will be assisted with the ebrake. Also charges the battery during every braking manouvre.
When the weather permits i will make a video with my gopro.
I only find that battery in holland, is this the only place it's being sold? i think it derives from the super soco CPX scooter, atleast from what i find on MCN
Did a test drive today and i am pretty pleased with the results, constant speed of 60km. The regen braking is really good, just tip the front brake lever and the bike stops pretty quick on the electronic brake.