Quoted from Strummy:
Those are nice. Any recommendations on which to buy?
Sorry, we have great power so I don't need to use these, but I would just add up the power requirements of what you intend to plug into it if all of them were on at once and use that as your guide. Probably one of these per each 3-4 pins if your plugs are on a 15amp circuit. It would definitely solve your low power issue during the day and overvoltage at night.
One tip, though. Make sure the plug is 5-15 and not the 5-20 because the 20amp plugs are usually safety plugs that will not plug into a "normal" 2 prong+ground outlet as they have one of the blades turned sideways on purpose.
Looks like an LC1200 or a LS604WM are the best choices from what's up there for 120v 4 outlet with a standard plug.