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PlanePower Alternator OUT lamp ON but still charging?

RudiGreyling

RudiGreyling

Well Known Member
Hi Guys,

I have PlanePower AL12-EI60/B in an electric airplane RV7, with 220 hours on it.

Yesterday during flight the Alternator Out Lamp started flickering ON and OFF and then Finally stayed ON. Now though it is indicating the Alternator circuit OUT permanently the Alternator IS CHARGING, viewable on my Amp Meter.

I have not been able to open up and check yet, so I thought it easy to ask online first so that I go armed with information next weekend in search of the fault.

Is this an early indicator the alternator is going to break? Or how can I go about finding the ALTERNATOR OUT LAMP fault? Anyone Experience this before?

Thank you
Rudi
 
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first things first....

Hello Rudi, great to hear from you. I'll have to look at your schematics and familiarize myself with your setup (I don't have a PlanePower alternator) but the first thing I would do, regardless of your schematics is to measure the field wire voltage from the voltage regulator to the alternator. Does your alternator have a built in internal voltage regulator? If it's the usual 12 v system, and the voltage is low... like around 3 volts, the voltage regulator is telling the alternator not to work very hard. If it's pushing towards 12, then it's telling the alternator to work as hard as it can. We want to measure this throughout the RPM range. Obviously we don't want the battery to overcharge so we have to be careful and make sure the system itself is not malfunctioning. If you can get us that particular information then we can go from there. The next thing to do is to find out what makes the light go on... is it a current sensing relay of sorts? Or is it a light that goes on when a wire shorts to ground and a particular value drops to zero? If it was intermittent and then is on steady... that is wonderful... because then we can find the fault instead of chasing an intermittent fault that is hard to duplicate.. that seems to point to something either having a faulty ground or maybe a wire chaffing on the airframe... again I would have to look at your schematics to see.... Do you have a double sided Master switch? There have been a lot of things that "were broken" but only had a bad ground. Best of Luck!!! Please feel free to email anytime or PM. Please keep us posted.

Best
Brian
 
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Assuming positive ammeter indication and bus voltage 13.8-14.5, the white wire is chafed and grounded somewhere between the light and the alternator plug.
 
Feedback Time:
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I don't have a chaffing wire. I Multi-metered the alternator out lamp wire at the back of the Alternator plug pin to the airframe ground and there is no conduction, so it is not earthed. So it means that wire is sound.

As soon as the master comes on engages the alternator, then that wire is earthed. Obviously I can't multimeter it with the engine running :mad:

I flew twice this weekend and the problem still exisits. It is Charging 14.3 volts initially after engine start and 10Amps, then it settles down to about 12.5 volts and 5 amps, after it rejuiced the battery what the starting took out, just servicing the airplanes consumption.

The Alternator Out Lamp still stays on the whole time...

Any other suggestions?

Thanks in Advance,
Rudi
 
RudiGreyling said:
Feedback Time:
============
As soon as the master comes on engages the alternator, then that wire is earthed. Obviously I can't multimeter it with the engine running :mad:

Any other suggestions?

Thanks in Advance,
Rudi
Click to expand...

Of course you can. Make a couple of extension leads for your DMM, with alligator clips on the ends. Attach to the circuit you want to meter, and tape the leads along the fuse back to the cockpit. Measure in complete safety. :)
 
RudiGreyling said:
Feedback Time:
============

It is Charging 14.3 volts initially after engine start and 10Amps, then it settles down to about 12.5 volts and 5 amps, after it rejuiced the battery what the starting took out, just servicing the airplanes consumption.

The Alternator Out Lamp still stays on the whole time...

Any other suggestions?

Thanks in Advance,
Rudi
Click to expand...

At 12.5 volts, the alternator is not charging...........:( At 12.2 volts, the battery is only 50% charged. With the motor running, you should be reading 13.8 to 14.2 volts.

After shut down, the reading should be no lower than 12.8 volts for a 100% charge for an AGM battery after it cools off. 12.5 volts is a 75% charge.
 
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Hey 👋🏻 just found this thread years later… what ended up being the problem and solution to your alternator light issue? I have a plane power alternator with inop light that did the exact same thing yesterday, was wondering what you found out
 
n8wyman said:
Hey 👋🏻 just found this thread years later… what ended up being the problem and solution to your alternator light issue? I have a plane power alternator with inop light that did the exact same thing yesterday, was wondering what you found out
Click to expand...
Ignoring the light for a moment -- what did the system voltage indicate? Typically, if the alternator is working you should see a buss voltage (the buss where the alternator "B" lead is connected) at ~14.4Vdc. If the alternator field is "On", and the buss volts are ~12.5V (AGM/VRLA/LeadAcid battery) or ~13.1V (LiFePo battery) - then the alternator is NOT producing current.

Check the "B" lead connection both ends of the wire.
Check the "Alt Field" lead connection, both ends of the wire.
Check the belt, is it tight but not over tight, lots of black dust evident?

The lamp output will indicate if the alternator is energized (alt Field has +12V) but no output and similar issues.

In my case, I had a broken wire from the stator windings going to the diode pack.

Cheers.

B
 
I would take the warning light out of the system, keep things simple, get a voltmeter and keep it in your scan, you shouldnt fly without one, the most important instrument in your electrical system.
 
n8wyman said:
Hey 👋🏻 just found this thread years later… what ended up being the problem and solution to your alternator light issue? I have a plane power alternator with inop light that did the exact same thing yesterday, was wondering what you found out
Click to expand...
I am disappointed whenever I see this and it is pretty common across many forums...
Some shlub has a problem (no offense Rudi) and asks on a forum.
Many or a few members chime in with experience, expertise, and just 'guessing' ....
The OP gets their wife's minivan fixed and then,,,,,, nothin

No feedback, nothing to be learned, not a clue!
AND all the members who 'helped' (for free) they get no recognition nor knowledge if they know if their advice helped.

Please folks, post the answer to your question when you finally fix your (your fault here)
 
bjdecker said:
Ignoring the light for a moment -- what did the system voltage indicate? Typically, if the alternator is working you should see a buss voltage (the buss where the alternator "B" lead is connected) at ~14.4Vdc. If the alternator field is "On", and the buss volts are ~12.5V (AGM/VRLA/LeadAcid battery) or ~13.1V (LiFePo battery) - then the alternator is NOT producing current.

Check the "B" lead connection both ends of the wire.
Check the "Alt Field" lead connection, both ends of the wire.
Check the belt, is it tight but not over tight, lots of black dust evident?

The lamp output will indicate if the alternator is energized (alt Field has +12V) but no output and similar issues.

In my case, I had a broken wire from the stator windings going to the diode pack.

Cheers.

B
Click to expand...
Interesting…. I’m not a hundred percent sure yet, I was flying solo, but here is what I noted…
Light came on, I cycled my alternator switch (I have a dual switch master/alternator) light stayed on. With the switch off, my engine monitor saw the voltage dip to 10.9v. With the switch on, jumped back to 12.4v, which is not where it should be, but it’s doing something..

The windings going to the diode pack… those are in the alternator? Not the external regulator, correct?
 
n8wyman said:
Interesting…. I’m not a hundred percent sure yet, I was flying solo, but here is what I noted…
Light came on, I cycled my alternator switch (I have a dual switch master/alternator) light stayed on. With the switch off, my engine monitor saw the voltage dip to 10.9v. With the switch on, jumped back to 12.4v, which is not where it should be, but it’s doing something..

The windings going to the diode pack… those are in the alternator? Not the external regulator, correct?
Click to expand...
Alternators are EXTREMELY SIMPLE here’s a great article overhauling a 67 Cessna alternator, well the article is really a 63 chevette alternator but the first Cessna alternator was the exact same alternator https://www.motortrend.com/how-to/1...hevy-alternator-adding-solid-state-regulator/
 
if its only putting out 12.4 your vr is probably fked up, probably been low awhile but you never new because you werent checking your voltage every flight, or were you? I dont block out of chocks until I turn my alternator field on and check the increase in voltage, and than continually monitor it during the flight, I dont have annunciation light for low volts, I watch it the whole flight, scan it every minute or so
 
FabricGATOR said:
I am disappointed whenever I see this and it is pretty common across many forums...

...Please folks, post the answer to your question when you finally fix your (your fault here)
Click to expand...

The OP last visited the forum in Nov 2022. Unless he's subscribed to this thread, I doubt we'll hear back from him.

Agreed. It's frustrating when the resolution is never posted.
 
Dad's RV-10 said:
The OP last visited the forum in Nov 2022. Unless he's subscribed to this thread, I doubt we'll hear back from him.

Agreed. It's frustrating when the resolution is never posted.
Click to expand...
I should have my spiel typed out so I cut and paste it.
I have taken on a crusade to raise awareness of this ever since I experienced the frustration of dead end threads years ago.
It is happening everywhere... every subject,,, every forum
 
Hello all, I had the same few years ago, light on and still charging. 50 hours later, it was completly out.
I opened it and found the output wires from the internal windings broken very short from the windings, all the wires.
In your alt, I suppose one of the wires is broken, still working on 2 from the 3 windings but...
Sure it's your problem, so switch to automotive alt from denso ($150 vs $2000!)

Xavier
F-PXRV
Pirates X-ray flight formation
 
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