I've thought about this for so long and it's a little sad but I'm gonna try explain it as good as I can with my No Med Adhd Brain™
Okay so you know how like when Denki uses his quirk people obviously need to shield themselves from his attacks even though his wattage limit is considered low (even tho it's rly not but that's not the point)
We also that quirk discrimination and fear is a big thing in the hero society.
Well I've always thought about how much some people might be taught to fear electrical quirks (and anything similar but for the sake of the post we're gonna go with electrical as an example)
Kaminari is a social butterfly. This mixed with some asshole kids in elementary probably led to him not particularly liking his quirk and how little control he had over it. I headcanon that Kaminari's limit is self-inflicted because he didn't want his friends to think he was going to shock them. As he got older that limit grew with him, but now he has a hard time raising his limit to a higher wattage because he's so used to not letting himself go over said wattage.
That being said he obviously still has a limit, but I do think he has a lot of potential to be stronger. I just think the limit is higher than he lets it be.
I can expand on this but I just needed to get it out of my system
