We have been down for maintenance since May. Worked through some oil temperature and pressure issues and did our first 2-up flight over the airport. Shortly after this picture was taken, voltage went over 15. The EarthX battery isolated itself and a total electrical failure ensued.
Did you figure out why the voltage went up?
Yep - discovered the bolt on the negative battery terminal was missing. It must be out in the countryside somewhere.
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Wow, I can imagine that bolt getting loose and rattling for who knows how long before getting free. Those threads are not short.
Several years ago I had an incident in my Sportsman, which is electrically dependent. I managed to overheat my one EarthX battery and the voltage became unstable. The engine could have shutdown but the charge system hung in there. Since then I made four changes one of which I encorperated into the Sonex. I added a backup alternator and a second bus with it’s own (second) battery and a cool air blast tube. Finally I added a very large capacitor into the charge system.
The Capaciter is what I also put on the sonex. In the event the battery takes a vacation the capacitor helps stabilize everything and enables the voltage regulator to better do it’s job.
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Glad to hear you found a cause, Bryan. Did the (brief) overvoltage take out any components?
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Evan, everything seems to have survived. I may have also figured out my high oil temps. Oil read 15F higher than ambient this morning. Cycled the connector and it was good. I’ve had trouble with that molex connector before and I’m going to replace it at the 10 hour retorque.
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Brock,
I was really glad to have gravity feed fuel and magnetrons. This was our third failure. First was the original VR losing its mind at night. Second was the screw on the master breaker feed coming loose. And third is the recent event. I’ve also had an alternator failure in IMC in a PA28R180. Field wire came off.
Beautiful pictures and I enjoy your videos! Glad you solved the charging issue.
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I managed to find drilled head metric bolts for the battery terminals of my alternator dependent (no magnetron) airplane.
Hmmm, do those get saftied to each other with # .051 safety wire? j.k.
I’m interested what you safety the positive terminal to also.
Torque time - Adam flew a couple hours today to get us to the 10 hour head torque. Oil temp is still high, 210 at the top of the climb about 3000’ AGL. Then it was 190-195 in cruise. Hopefully it’s just the new bearings breaking in.
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I flew solo for an hour at lunch today. Then we went up after work for an hour and a half. We have 376.5 hours total time. I need to shave.
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Motorcycle and powersport batteries typically have a side and a top entry point to screw the lugs to. I use the top entry point, and safety to the side. I’d post a picture, but I have the cowling all buttoned up.
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No nifty pictures but I reset my night currency this evening. Winter and short days are coming!
a late read on this, but I fully concur with a large cap on the buss somewhere, with a surge surpressor for start up inrush currents. The charging system is singly phase, and has need tor the cap, at least to elliminate voltage fluctuations durring lower rpm ops. dont ask how I know this. I used a portable o’scope to i.d. the situation. The voltage rating of the cap should be a good number of times the buss voltage.If I remember correctly (6 yrs ago/) it was at least 63vdc
C77-79C-BUU-C37-1C8. Stamp at Brennand north of Oshkosh, gas stop at Dodge County, stamp and Kelch museum at Brodhead, EAA chapter 22 fly-in lunch at Cottonwood.
KOSH:
79C downwind:
They have an awesome building.
Counter inside:
It has a 2 lane bowling alley:
Kelch museum at Brodhead. I parked in the shade!
Total 3.2 hours, max CHT 311, max oil temp 197.
At home, 18013G24KT at nearby Rockford. 9/27 is our only open runway today. I was out of right pedal and turned left across 27 a little, then had just enough.
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