UPC trouble!

I have a Tripp Lite BC-450 UPC, that works, but puts out 145 volts AC,
instead of the normal 120 vlots AC. I can't find any semiconductors
shorted, or overheating, it just runs at too high
an output. I'm using a fully charged acid 12 volt car battery as it's
source! Input anyone? Dani.

 

How are you measuring the voltage? Many meters will not give
accurate RMS readings with the modified sine wave waveforms
most of the UPS generate.

David