I would ask this:

Are they ALL always in the sun at the same time? My solar panels vary. (I have two groups, all in serial, but the two groups are parallel).
My NW group gets lots of morning sun, but little to no late afternoon sun.
My SE group gets the late afternoon sun. Both get mid-day sun.

So frequently I'll turn on just the NW panels in the morning, turn on the SE panels when the sun hits them, and turn the NW panels off as the sun leaves them.