Sounds like it's low voltage. Do you know what it is? When the voltage drops and you have an AC running, the current draw goes up and not down. If you don't know what the voltage is, try running a couple of 1500 watt appliances like a hair dryer and toaster which should draw near 30 amps at 120 volts. If it holds, then try adding a smaller appliance if you have one and see if it still holds. If it does, it's very likely low voltage causing the problem. When running appliances like toasters, hair dryers, coffee makers, etc., the current goes down when the voltage does.
Low voltage is a common problem in the summer time with so many using AC units. You really want to know what the voltage is when running AC units in the summer because when it gets down to 105 volts and below, it will damage an AC unit. It was probably okay at night because people are not running AC units and other heavy loads and the voltage was probably closer to normal.
If you are at campgrounds with low voltage and really want to run an AC unit or two, there's always an autoformer you can use like the Hughes or Franks units.
The campground that we are currently at for a couple of days in eastern Wa. is having major issues and has asked people not to use their AC units. It's been bad enough that their main breaker for the whole CG has even tripped.
