Voltmeter for the external backup power

[pwhaley6347]

I'm getting a 7.2 volt reading on my 180. My understanding is that if I don't have power applied to the EFIS DB25 pin 15 it should read zero. What am I missing? The condition was as follows: Airplane in the hanger, powered by the aircraft battery, the internal battery was charging.

 

[dynonsupport]

A few questions: Which volt reading are we talking about? Is it the graph on the EMS side of things, or one of the line-items on the EFIS display?

If it's the "I" line item, that's the internal battery votage. 7.2V is extremely low, and may indicate that the FlightDEK-D180 is having trouble charging the battery (fixed in the latest firmware), or that there is something wrong with the battery itself.

 

[pwhaley6347]

Sorry about the lack of info. It is the "E" voltmeter on the EFIS screen.

 

[dynonsupport]

Paul,
We'd expect that the "E" would read zero if nothing was hooked to pin 15 on the harness. But then again, with nothing hooked to it, the wire "floats" and might achieve a non-zero voltage.

Having it at 7.2V won't harm anything or cause weird behavior. If you really want to, you can try hooking that wire to ground. This should set it to zero and won't hurt anything in the EFIS.