I've marked a few possible places for additional battery mount.
What do you think is the most reliable place to mount battery in terms of ergonomics of the bike? Also, how to ensure the parts are having waterproof connection?
Model is OIO City Bike
Additional specs:
Wheels diameter: 26 inches
Motor: 350 Watt, brushless, maintenance-free
Speed: 35 km / h
Weight: 21 kg
Load: 120 kg
LCD Display (KBY-DISP KD21C): Indication of battery charge status, support level, speed
Number of gears: 21
Brakes: Disc
Frame: Aluminum
Battery: 36V 10.4Ah Li-ION