"whit3rd" wrote in message
...
On Thursday, July 9, 2015 at 9:29:58 AM UTC-7, Jim Wilkins wrote:

[about odd AC measurements on a DC/AC inverter]

If you have a (possibly sacrificial) way to heat water with the
inverter you could time how long a measured amount of room
temperature
water takes to boil on the inverter and on Netzstrom. They should
be
pretty close to each other.

Bingo! An electric coffeemaker's brew time for a given water fill
is
a better RMS voltage meter than most inexpensive electronic meters.

The heater's power draw would have to be within the capacity of the
inverter and battery, perhaps an immersion heater or single-serving
hot pot for a dorm room or office desk. A 1000W coffee maker would
pull over 80A from the 12V vehicle battery.

-jsw