I've kept at this thing for a month, and now have the whole thing running except... and it's a big exception... It only works at partial power. Does anyone know why this system works with my three groups of 9 panels in the morning and afternoon, but not at midday?

It seems to have something to do with the total amperage ... A typical day works like this. I start with all three strings running, when they get to about 10 or eleven amps, the inverter shuts off and reboots... If I take out a string it runs fine for another hour or so until the sun is high enough to reach about ten or eleven amps on the two strings. When I cut back to one string, or about 5 amps, it runs all day without shutting off.

Seems my peak is just over 10 amps. I assume it has something to do with the + ground. It uses the lay in lugs and some are old... they are held in place with self tapping screws. Would machine bolts be better? How about the di-electric grease? or is it even a grounding problem? Can anyone point me in the right direction?
thanks
Wing

Some detailed pics will help and some detailed measurement's as well

DC: Volts, Amps and the VA (Watts) both unloaded and loaded
AC: Volts, Amps and the VA Both unloaded and loaded

Check the DC side, the connections, wire losses, panels and such for loose connections.

The controller(Inverter) Check it for cleanness, power hook ups, hot spots.

List the results and it will assist us in pinpointing the problem area for you, that and it will greatly assist you to do some more research and learning of how grid tie systems work.

don't mess with the lay-in ground screws, they are self-tapping and should last the life of the system. Even if they get nasty on the outside, the hidden threads are what's making contact.

Noon shutdown, has to be too much power, not enough cooling, or the array is loosing voltage in the heat, and dropping below the mininum input voltage.

have you run your system through the string sizing calculator ?