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Voltage at 15.5

Lemos

Active Member
My voltage is at 15.5 according to my vpx. Dynon Skyview volts and amps show 0 but I’m not sure they’ve ever worked properly as I haven’t really paid attention.

Any suggestions for what to check? Heading to Oregon in the morning and then will be parked for two weeks so I can order whatever parts are needed from the mothership and then pick them up.
 
Your voltage regulator is failing. If you have the standard Van’s Firewall Forward Plane Power alternator, it has an internal regulator. These can be repaired if you know what you are doing.

Carl
 
Your voltage regulator is failing. If you have the standard Van’s Firewall Forward Plane Power alternator, it has an internal regulator. These can be repaired if you know what you are doing.

Carl

It has the Nissan Denso alternator. Are the voltage regulators pretty easy to come by in the Portland area? I’d assume yes.

Any issue flying it about five hours? Avionics are rated to 24+ volts so I’m thinking no problem.

What concern, if any should I have about flying it as is?
 
Take your alternator to a shop for repair, or just replace it before you do your next engine start.

15.5 VDC buss will degrade your battery in short order. I also suspect you have stuff in your plane that will not play nice, like all your stuff besides your 24 vdc avionics (servos, lamps, lights, strobes, boost pump…..)

Carl
 
Not only are there the dangers that Carl pointed out, but the danger of the voltage going higher yet. If it goes above 30, avionics could be ruined, costing thousands. Of course the VPX could be lying. Verify the voltage with a voltmeter.
 
Thank you for the information.

Had a wonderful flight to Hillsboro Oregon today. Never saw above 15.4 volts and experienced no issues. Well not entirely true; forgot to turn on the alternator after start today and right after liftoff got a VPX Fault. But turning on the alternator fixed that. :eek:

I’ll call Vans on Monday and see if they can ship me a new alternator. Has anyone had any issues getting an A&P mechanic to install an auto alternator in their RV?
 
My advice, which is worth what you paid for it, is to get this fixed ASAP.

What kind of ignition and fuel system do you have? What kind of battery? Over 15v means something is wrong, and it could start smoking other things on your aircraft.

If you don't yet have a good "EAB-aware" A&P, I'd find one and make him/her fall in love with you since you are going to have a very close relationship over the coming years. Swapping out parts that might not be broken is an expensive and time-consuming way to troubleshoot.

I'd also recommend getting hooked up with the Savvy Aviation guys - https://www.savvyaviation.com - you can use them to see what's happening in your engine. They might also be able to recommend an A&P for you that's a reasonable distance from where you live.

Another option is to call these guys, as they probably know someone on the left coast that does what they do: https://baselegaviation.com/

A small investment now will help ensure that your aircraft provides you many years of safe and enjoyable flying.
 
My advice, which is worth what you paid for it, is to get this fixed ASAP.

What kind of ignition and fuel system do you have? What kind of battery? Over 15v means something is wrong, and it could start smoking other things on your aircraft.

If you don't yet have a good "EAB-aware" A&P, I'd find one and make him/her fall in love with you since you are going to have a very close relationship over the coming years. Swapping out parts that might not be broken is an expensive and time-consuming way to troubleshoot.

I'd also recommend getting hooked up with the Savvy Aviation guys - https://www.savvyaviation.com - you can use them to see what's happening in your engine. They might also be able to recommend an A&P for you that's a reasonable distance from where you live.

Another option is to call these guys, as they probably know someone on the left coast that does what they do: https://baselegaviation.com/

A small investment now will help ensure that your aircraft provides you many years of safe and enjoyable flying.

I have Lightspeed ignition. I have two fuel tanks with a fuel pump. Odyssey battery.

I used Savvy with a previous airplane and they cost me a great relationship with my then long time AP mechanic. They tell mechanics how to do their job and upset them. 7 year relationship went up in smoke.

Will give Base Leg Aviation a call.
 
Here is the recommended range from the manufacturer. I was always told anything above 14.8 boils the electrolyte out of the cells over time even in a gel cell battery.
If the battery is used in a starting application, the alternator should provide between 14.2 and 14.5 volts at the battery terminals. In cycling applications, the absorb voltage should be between 14.4 and 14.8 volts, while the float setting (if applicable) should be between 13.5 and 13.8 volts.
 
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Turns out, Vans does not sell the Nissan Denso alternator. So, I have sourced one on eBay and am having it sent home. I’ll change it upon my return to California in about a week.

Thank you for the help getting this troubleshot.
 
Do you mean Nippon Denso? (Nissan is a car/vehicle company; whereas Denso is a Japanese component manufacturer.) :eek:
 
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