I bought a plane.

[Scudrunner]

Excellent, those pussies who go easy on the weld trying to make it look nice are just asking for trouble.

[Scudrunner]

Found the voltage regulators both on the front engine firewall .

A64629C4-E4B3-4570-A2F9-706646A10813.jpeg

C00A1FC5-66C2-43B6-9445-B4793D5D3F6F.jpeg

A92D198A-0CAF-4748-87E2-73CF0293BFA8.jpeg

[Colonel]

Fascinating! Please click on

https://lamartech.com/wp-content/upload ... 145584.pdf

Note that the VR-500-0101 maintains 27.7V and the VR-500-0102 maintains 28.8V

Hard to read your labels, but all you have to do is put a voltmeter across
the red wire (which doubles as both power and control) of each. With
the engines running (ahem) and report back the voltages measured.

These are very simple boxes. Black is ground, blue is output (to the alt field)
and red is the magical power/control wire.

If the voltages at the red wire of the regulator are different, then it's the
regulator.

If the voltages at the red wire of the regulator are the same that implies you
have some contact resistance upstream of it. This resistance - generally at
corroded connectors - causes a voltage drop before the regulator, and results
in the regulator maintaining a higher upstream system voltage, even though
the voltage regulator sees the lower voltage.

I actually find this sort of diagnosis fun. It's like an IQ test. I always finished
them before the other kids.

[CpnCrunch]

29.3v sounds high. If the voltage is too high it will overcharge your battery and reduce its life (or worse).

https://www.aviationconsumer.com/mainte ... -it-right/

“ Overvoltage can be worse than undervoltage, especially for a sealed battery. We witnessed a Concorde battery self-destruct when the charging system in a Cessna 210 reached nearly 30 volts, and stayed there for a multi-hour trip at cruise power.”

[Colonel]

The correct system voltage depends on temperature and the technology of the battery. Roughly, the newer the battery technology, the higher the voltage.

As a very rough rule of thumb, you don't want to see below 13.5V over 14.5V for very long in a so-called "12V" system. Brief dips and spikes are probably ok after start, but ...

Doubling the internal capacity of the battery, that translates to anywhere between (13.5 x 2 =) 27V and (14.5 x 2 =) 29V would work.

My personal preference for 12V is high-ish 13V's (eg 13.8V) which translates to (13.8 x 2 or) a bit under 28V.

[Colonel]

We witnessed a Concorde battery self-destruct when the charging system in a Cessna 210 reached nearly 30 volts, and stayed there for a multi-hour trip at cruise power.”

What an idiot - sat there and did nothing for hours.

Lesson learned: If you see an over-voltage which does not kick off, pop the alternator
field and run on battery power for a while. Run it down a bit, then manually turn on the
alt field and charge the battery up to 14.5V or 29V as applicable, then pull the alt field again.

Rinse, lather, repeat and get it on the ground somewhere that can fix electrical systems.

[Scudrunner]

They are definitely both VR500-101 voltage regulators. the battery was replaced last year and if my squinting at the maintenance log scan is correct it appears to be a “CONCORDE RG24-15M PLATINUM SERIES SEALED LEAD ACID AIRCRAFT BATTERY” https://www.aircraftspruce.ca/catalog/e ... 24-15m.php

Again partner in her has the maintenance logs at home and is away working at the moment. I’ll get my hands on them soon.

Next time I’m out there I’ll do some more playing. In the meantime when I do Fly I can just shut off the rear alternator just in case.

Question: can those be adjusted to correct voltage or is it a buy a new one scenario? I can’t find anything (thanks for the link) about that with those regulators specifically.

[Big Pistons Forever]

Hey Scud, I got that exhaust manifold welded up for you.



4F321F75-1E7D-49AF-BE9F-3CB1B746E1CC.jpeg

I once saw a C 172 with an exhaust manifold that was almost as bad. It had more beads than an Indian Princess. I guess the guy just kept on welding the cracks and then kept on wondering why it just cracked again a bit further down.

[Big Pistons Forever]

Not very electrical savvy but I have seen a bunch of weird electrical shit fixed by cleaning up the ground connection to the airplane. Might be worth unfastening the ground wire connection and cleaning up the contact surface.

[Scudrunner]

Not very electrical savvy but I have seen a bunch of weird electrical shit fixed by cleaning up the ground connection to the airplane. Might be worth unfastening the ground wire connection and cleaning up the contact surface.

Agreed that would be my first guess, just did that on my tent trailer lol

Tons of fun learning a new plane taking panels off.