JPI930 and indicated voltage
I just finished installing a JPI930 in a clients plane and when the system is active, the display shows 12.5V. The customer hooked up a volt meter to the battery and it showed 13.9V. He is insisting that the JPI should read the same. I explained to him that the reading on the JPI is from the "Bus" and the reading from the battery is directly from the alternator. I have installed three (3) of these units and have never had the JPI930 show the same voltage on the display as that coming from the alternator. The JPI is getting the voltage directly from the pick-up leads off the shunt. Is there anything else I can do and how do I explain to this pilot that the unit is displaying properly?
Thanks for the help.