Does the reactor level used with a shield make a difference?

Hello,

I have a question about the shield and reactor.

The Small Shield Generator has a shield strength of 15,000 points.

Does it make a difference whether the batteries come from a Level 1 or 3 reactor?

The 15,000 points don't increase.

But I think the shield also loses batteries when it's not being attacked but is still powered on, right?

I'm a little unsure right now xD