2007 SR22 NA Electrical Problem

While at cruse, on several occasions, a Batt DISCH warning illuminated. DISCH varied between 3A and 30A. Went to 8A DISCH for about 5 seconds several times intermittently spikes to 41A (less than 5 seconds).

BATT showing 0-2A normally on this flight M. Bus 27.7, and E. Bus 28.7 during the DISCH

All batteries have checked good.

No additional electrical loads applied or removed during this period

I am thinking it is not an alternator problem since both alternators were operating normally (ALT1 9A, ALT2 6-8A) when the DISCH occurred.

On last flight GPS 1 breaker tripped.

Slight smell of electrical in cockpit

Unable to reset

Any suggestions are appreciated

My first guess is a short caused by a bare wire that grounds, then not, with bumps and vibration. That explains the strong discharge, the intermittent nature, the breaker pop and the smell. I would fly no further.

Has the issue recurred since the breaker tripped? If not, I’d say you found your answer … an intermittent short in the GPS1 power supply or wiring harness.

A hard tripped breaker is not something to mess with. Leave it popped and get to an avionics shop to trouble-shoot.


MCU 130:

Check internals for loose battery feed current sensor (shunt).

Reseat external connectors on MCU

Reseat connectors on DAU.

GPS1? What radio brand?

Battery feeders checked, not problems found. will reset connectors on DAU and advise.

Bothe GPS are Avidyne 440.

Thanks for your feedback

i switched the # 1 and #2 GPS, the breaker did not tripped. Flew locally for about an hour yesterday. The high DISCH did occur intermittently several times.

Thanks for your feedback

Hi Michael,

Were you able to find out anything further on what was happening and or the “culprit” We have a 06 NA 22 having the same issue with Large Batt Dschg numbers intermittently. Positive ALT 1 and 2 amps and M. Bus and E. Bus numbers exactly where they should be. Thank you