Also, just something new I learned. If you live rural, or where power lines are old, it may be prudent to get a Voltage Regulator Surge Protector. The reason being is, I found out here, the parks power systems are outdated, and with everyone stepping down their 50amp RVs to 30amp, was severely crippling the power system. The voltages dropped constantly on a large sine wave (I forget numbers now, I know voltage dropped below 100 off 120v plug). I now know why two computers PSUs popped, a mother board died, and a game console popped.
Every since getting a power regulator surge protector, I haven't had any issues, and the voltage leaving the strip is steady.
PS I think emergency power supply backups use voltage regulators to charge the battery and delivery power, not positive though. They'd probably say. I know Danny's does.