Electro Ball inflicts more damage the

faster the user is compared to the

target. Therefore, the higher user's

Speed stat is than the target's, the

greater the damage. Base power is

calculated as follows:

- 150 base power, if target's speed is lower or equal to ¼ (25%) of user's

speed.
- 120 base power, if target's speed is greater than ¼ (25%) of user's

speed and lower or equal to ⅓ (33%) of user's speed.
- 80 base power, if target's speed is greater than ⅓ (33%) of user's

speed and lower or equal to ½ (50%) of

user's speed.
- 60 base power, if target's speed is greater than ½ (50%) of user's

speed.

Definitely not Bulbapedia

So basically max power is 150.