afward Posted January 4, 2022 Report Share Posted January 4, 2022 Just want to double check things... My 12v system tends to run around 15v in-flight. It used to run lower, but has always bounced around quite a bit, especially the amperage. The alternator isn't the issue. Any ideas why and if I need to replace the regulator? Quote Link to comment Share on other sites More sharing options...
PT20J Posted January 4, 2022 Report Share Posted January 4, 2022 Nominal voltage should be about 14 to 14.5 volts and should be steady. I would check the field connection and grounding first. Avionics shops are often better at troubleshooting electrical systems than A&Ps. There is a troubleshooting chart on PlanePower’s website. Skip 2 1 Quote Link to comment Share on other sites More sharing options...
Bartman Posted January 4, 2022 Report Share Posted January 4, 2022 Mine runs 13.8 volts and has been consistent for 10 years with the solid state voltage regulator. 1 1 Quote Link to comment Share on other sites More sharing options...
afward Posted January 4, 2022 Author Report Share Posted January 4, 2022 Hmmm... Sounds like I need to work through the troubleshooting flowchart. Hopefully it's something easy (and cheap!) to fix. Quote Link to comment Share on other sites More sharing options...
1964-M20E Posted January 4, 2022 Report Share Posted January 4, 2022 The plane power voltage regulator is adjustable. I'd put it at 14.0 to 14.1 V, The amps may be varying if you have strobe light when it is charging between flashes 1 Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted January 4, 2022 Report Share Posted January 4, 2022 You need an digital voltage meter and the troubleshooting chart from plane power or Zeftronics. Be very skeptical of opinions on what it is and/or replacing parts because lots of mechanics don’t know how to troubleshoot this. Its in the troubleshooting, but definitely check the bus voltage, input voltage to the Voltage regulator, and the field wire voltage. Difference between those will point you where to look next. Field voltage will be less than the other 2 by a volt or two, but the other two should be almost exactly the same. It’s on the troubleshooting guide. 2 1 Quote Link to comment Share on other sites More sharing options...
MikeOH Posted January 4, 2022 Report Share Posted January 4, 2022 26 minutes ago, afward said: Hopefully it's something ... cheap to fix. Oh, now you've gone and jinxed yourself! 1 Quote Link to comment Share on other sites More sharing options...
apriav Posted January 4, 2022 Report Share Posted January 4, 2022 Voltage should be 13.8 - 14.2 volts on the main bus. Check voltage on the field wire, while running, it should change with loads added or taken away (more with greater load). If your ammeter jump and field voltage jumps together turn loads on or off for locating trouble. Field resistance is goog to look at, with battery off and field wire removed check resistance to ground. Should be constant while prop is turned. Changing resistance indicate brush or ring problems. 1 Quote Link to comment Share on other sites More sharing options...
Greg Ellis Posted January 4, 2022 Report Share Posted January 4, 2022 10 hours ago, afward said: Just want to double check things... My 12v system tends to run around 15v in-flight. It used to run lower, but has always bounced around quite a bit, especially the amperage. The alternator isn't the issue. Any ideas why and if I need to replace the regulator? Like what has been stated, I would run through the troubleshooting process but I had this happen to me. The regulator had to be replaced. The replacement is rock solid at 14 Volts. And as has been stated, they are adjustable. I adjusted the old one when it was flaky and it would stay at the proper Voltage for about 1 flight and then start creeping up. Replaced it with a new regulator and everything went back to normal. 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted January 4, 2022 Report Share Posted January 4, 2022 Forever a 12v battery systems voltage is 14V plus or minus .2, may be lower if amperage is high, but 15V puts you into the battery off gassing and will shorten its life. ‘Before you do anything verify voltage with a known good multimeter, often installed gauges aren’t very accurate. 1 1 Quote Link to comment Share on other sites More sharing options...
rbridges Posted January 4, 2022 Report Share Posted January 4, 2022 17 hours ago, Bartman said: Mine runs 13.8 volts and has been consistent for 10 years with the solid state voltage regulator. My previous alternator ran 13.7-13.8. I had it and the voltage regulator replaced, and they read 13.7-13.8. 1 Quote Link to comment Share on other sites More sharing options...
Igor_U Posted January 4, 2022 Report Share Posted January 4, 2022 20 hours ago, PT20J said: Nominal voltage should be about 14 to 14.5 volts and should be steady. I would check the field connection and grounding first. Avionics shops are often better at troubleshooting electrical systems than A&Ps. There is a troubleshooting chart on PlanePower’s website. Skip This was confirmed to me recently by Hartzell (plane power) support; specifically 14.2V +/-.3. Plane power troubleshooting is here: https://planepower.aero/wp-content/uploads/2018/02/Troubleshooting-Single-Engine-Externally-Regulated-Alternators.pdf 1 1 Quote Link to comment Share on other sites More sharing options...
Marauder Posted January 5, 2022 Report Share Posted January 5, 2022 This was confirmed to me recently by Hartzell (plane power) support; specifically 14.2V +/-.3. Plane power troubleshooting is here: https://planepower.aero/wp-content/uploads/2018/02/Troubleshooting-Single-Engine-Externally-Regulated-Alternators.pdf I have a Plane Power alternator and voltage regulator. Mine is rock solid at 14.1V. To the OP - As others have pointed out 15 is way too high. Sent from my iPhone using Tapatalk Pro 1 Quote Link to comment Share on other sites More sharing options...
afward Posted January 5, 2022 Author Report Share Posted January 5, 2022 Thanks for all the suggestions! I did go through the PlanePower troubleshooting guide and found that the switch/breaker/enable wire need replacement (I'll figure out which one in particular once I go to fix it) and the aux wire from the alternator isn't driving the aux input on the regulator (which is wired to enable & sense??). Voltage drop across the VR is minimal so I think it's ok. Once those items are fixed I'll test and update here. 2 Quote Link to comment Share on other sites More sharing options...
afward Posted January 6, 2022 Author Report Share Posted January 6, 2022 Ok, it's fixed now. Turned out to be a bad crimp on one of the wires connecting the field switch. Amperage and voltage are now both rock solid. Thanks for all the pointers everyone! 3 Quote Link to comment Share on other sites More sharing options...
Ragsf15e Posted January 6, 2022 Report Share Posted January 6, 2022 50 minutes ago, afward said: Ok, it's fixed now. Turned out to be a bad crimp on one of the wires connecting the field switch. Amperage and voltage are now both rock solid. Thanks for all the pointers everyone! Cheapest fix you’ll ever get! Mine was low voltage. Turned out to be a bit of corrosion on the alternator output wire where it connected to the main bus. Unfortunately I only learned that after installing a new alternator, voltage regulator, field wire and master switch. Then i read an electrical engineering book, troubleshot it myself and fixed the connection. It was an expensive education. Quote Link to comment Share on other sites More sharing options...
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