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Fellow flyers I'm having what seems to be voltage spikes that disrupt my R-Dac and radio operations. Has anyone experienced problems with the factory voltage regulator? It is still keeping the battery charged....................Stay happy Tom Ryan. 0nex 74

Tom,

Give us more details about the voltage spikes (when do they occur, what voltages are you seeing and for how long, normal bus voltage when not spiking, etc). In the mean time, you might check the simple stuff like corrosion in the connectors from the alternator wires to the voltage regulator, the ground on the regulator (thru the case to the firewall), does the problem go away when the alternator is turned off and you're operating only on the battery?

Jeff

Hi All,

Last week, I experienced a battery charging problem shortly after leaving my home airport. Normally, after T/O, the battery voltage is increasing slowly up to about 13.8V after about 15 min of cruise flight. (I perform ground ops without the electronic ignition to preserve battery voltage whilst on the ground as the alternator is not putting any charge into the battery at low revs.)
Switching on and off the alternator switch and checking the breaker didn't improve things and I continued for a while on the magneto only before returning home to investigate.
No loose wires or connectors found, I replaced the regulator and did a ground run without result. Checked the alternator windings resistance and possible short to ground: all ok.
Went further and removed switch to find a shiny connector screw and a dark brown one!!! Apparantly corrosion had occured in that connector which showed green because of corrosion.
Replaced the 3$ switch and replaced both wire connectors and did a test run: all great!
I will now carry my old regulator aboard in case of....
Lesson learned: inspect and change the sheap component first before ordering the pricy ones!

Interesting that one is shiny and the other not. I suspect vibration loosened the connection and allowed it to heat up, accelerating the oxidation. 20Amps could easily do this. During my build, I became convinced that FastOn Spade terminals are the way to go wherever possible because they have fewer parts (no screw) and seem less prone to this issue. http://www.aeroelectric.com/articles/faston3.pdf

This is also an interesting failure in light of recent discussions on the forum about redundancy and failure modes. I'm not aware of any cases where a permanent magnet generator with our voltage regulators has overcharged the battery. I'm curious if its even possible to fail that way. Because of this, I chose to follow the plans and did not add a switch.

Hi Chris,
It was not possible to remove the screw, it was corroded onto the tab. The reason for the corrosion might have been a bad soldering of the wire connection?
I have no overvoltage protection installed btw.