PlanePower Alternator OUT lamp ON but still charging?

[RudiGreyling]

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

[brianwallis]

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

[DanH]

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.

[RudiGreyling]

Originally Posted by DanH

Assuming positive ammeter indication and bus voltage 13.8-14.5, <SNIP>

AFFIRM

Originally Posted by DanH

<SNIP> the white wire is chafed and grounded somewhere between the light and the alternator plug.

Thanks I will look and trace.

[RudiGreyling]

Feedback Time:
============
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

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

[cfiidon]

http://www.plane-power.com/images/tr...0C_ER14-50.pdf

The last line says "Call"

[Ted Johns]

Originally Posted by RudiGreyling

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

Any other suggestions?

Thanks in Advance,
Rudi

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.

[gasman]

Originally Posted by RudiGreyling

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

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.

[RudiGreyling]

Originally Posted by cfiidon

http://www.plane-power.com/images/tr...0C_ER14-50.pdf

The last line says "Call"

Cool, if they only had one for AL12-EI60/B since the connectors don't match.

Rudi