Fuel Cell Output Cap tweakable/config???

[Kerbals_of_Steel]

Is there a tweakable or config that can be adjusted to lower the normal 95% fuel cell output cap? I've got an ISRU ship powered by a combination of solar, stock fuel cells, and an Umbra/MKS nuke reactor. Right now the hierarchy of load is Solar > Fuel Cells > Reactor, and I'd like to drop the output cap on the fuel cells a bit (75-80% or so) so that the reactor is loaded first, and the fuel cell array just picks up the load when the reactor can't keep up. Alternately, I guess, is there a way to adjust the cap on the reactor so it fires up earlier?

[Maj Solo]

if you LEAVE the ship KSP is going to treat it as it had unlimited juice.