Alternator

[Jkeene02]

When I am flying at night i turn on my back lights strobes nav lights have a iPad plugged in in cruise ...: my voltage is all over the place from 14.7 -13.5 with that stuff off it never moves off 14.2 is this normal 

[irishpilot]

Voltage jumping is not good. Sounds like it is drawing more than it is producing with everything on. It could be high Amp or high voltage. Best to ground test with A&P.

Fly Safe,
Safety Forum Mod

[carusoam]

No, not normal...

Where are you reading the voltage from?

If everything is stable until these devices are on...

it may be the sensor or gauge is getting some noise...?

If the problem is real... the voltage regulator is suspect... what VR do you have?

got a second portable voltage sensor for back-up?  Some portable garmins have a voltage reading, as do some JPIs

PP thoughts only, not a mechanic...

Best regards,

-a-

[81X]

What year/model?  

If you have the master switch with the blade connectors on the back, clean them.  This happens about once a year in my 85 K and a good cleaning magically makes everything better. 

[Yetti]

What alternator?  What plane? What voltage regulator?

[Ragsf15e]

Similar to the switch contacts, circuit breaker for the VR.  Mine developed a low voltage situation over a couple years as the resistance increased.  Tried several expensive things before finally measuring the voltage drop across the circuit breaker and replacing it for$20 /Spruce. Fixed it.  Similar to the switch as mentioned above, you should be able to measure voltage drop across it.

Zephtronics has a troubleshooting guide on their website.  It’s not super easy to follow, but not terrible either.