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Flying Bozo

Alternator light

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Hope someone has an idea as to this problem. Alternator light stays lit for about 3 to 5 minutes after start and then goes out. All the time that the light is on the voltage is right up in the 13.7 volts. So it is charging. Then after it goes out it does not come on again. Next time out from cold start it does it all over again but not if I just make a stop like for something to eat it is OK and does not do that stay on thing. can anyone shed any light on this issue. We have re-tightened all the grounds.

Larry

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Fred, it has been happening for 6 or 8 months but it was charging anyway. It was more or less now and then for a while and now you can almost set your watch by it.

We tightened all the grounds etc no change. When the  light goes off and the rest of the day it is fine.

Hope someone can identify the issue.

Thank you,

Larry  N255CT 

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I had one customer airplane that acted that way. Never got to the bottom of things, but I suspected that it was the regulator or regulator connection.

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The friend who knows a lot about that type of things said he thought that too but had not seen the problem before.

So what did you do about your customer's problem...? Replace the regulator?

Larry

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It can be a loose battery terminal connection. If you can move a battery wire by hand it's too loose. It can be a bad ground, but most likely a bad connection somewhere.

Start at the battery. #1 culprit.

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Thanks Roger, we have been all over any wire that is able to be tightened. The battery too. However I will remover the wire and make double sure. Everything else to absolutely tight. When it first happened I was able to get a quarter turn on one of the nuts on the firewall but that changed nothing.

Still baffeled!!

Thanks,

Larry

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1 hour ago, Flying Bozo said:

The friend who knows a lot about that type of things said he thought that too but had not seen the problem before.

So what did you do about your customer's problem...? Replace the regulator?

Larry

Like yours it was charging fine, so nothing was done. I didn't have an extra regulator to try, and was not going to have the customer buy a new one just to try it out.

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Well Tom that is interesting. The problem has not been an issue because I have not had any long trips ans so was not concerned too much. However, I have to fly it to Tulsa this weekend from here in Arizona so wanted to see what I could do.

Your customer's problem is interesting because it sounds the same as mine. It does charge OK. So now is that customer still having the same problem or is it finally fixed?

Thanks for the comments.

Larry

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Larry, this has been happening to my CTSW for the last year.  There are times that the light stays on for about 5 minutes during engine warm up.  There are times that the light doesn't come on at all on a cold start.  I estimate 7 or 8 times out of 10 the light will come on when I first start the engine.  When the light does come on,  it  always goes out in a few minutes.  My situation is exactly the same as yours.  If I might fly and stop the engine for a while, the light never comes on again during my stops and starts that day and my volt meter shows high 13 volts charging.    I don't think that there is anything loose or else this problem would come and go during my flight and/or after stopping and starting during the day's flights.  Due to the number of complaints about our Ducati regulator, I am thinking this might be starting to fail but would think this would be intermittent during the flight.  I have taken some long flights lasting for a couple of hours and the light has not come back on.  I'll check for loose or broken wires and attachments.  If anything is found I will let you know and please do the same.

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I have had this same problem exactly as you describe. It ended up being a bad connector onto the regulator. The two yellow wires are the ones that carry the current for charging and are mounted in the black connector block. You can remove these wires / terminal spade connectors by pushing down on the small tab inside the connector block to slide them out, then just crimp on a new spade connector to the wire and just push it in till it clicks. You may also need to give the spade lugs a good clean up in the regulator.

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image.png.f9fd476b0b2d35802f93a261a271e42c.png

image.png.d6f56aac9d78342402ab6d38727496c5.png

 

The light comes on if there is a voltage imbalance in the circuit. It functions by using voltage potential to resist current flow through the light (there is always a tiny amount of flow, but not enough to light it up). If your generator output is poor, the battery will then power the light. Cause is usually dirty connections.

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Following from Corey's more detailed description of how the charging system works, when you get a bad connection from the generator the resistance goes up and so you have a voltage drop across the bad connector which will limit the current available for charging.   

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23 minutes ago, Anticept said:

image.png.f9fd476b0b2d35802f93a261a271e42c.png

image.png.d6f56aac9d78342402ab6d38727496c5.png

 

The light comes on if there is a voltage imbalance in the circuit. It functions by using voltage potential to resist current flow through the light (there is always a tiny amount of flow, but not enough to light it up). If your generator output is poor, the battery will then power the light. Cause is usually dirty connections.

Thanks Corey . . . very helpful.

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Ct9000, thanks for the heads up about the connections.  Corey, thanks for the details.  I've dealt with these blade connectors before on the regulator.  The little tabs poking out from the blade connectors that Ct9000 calls out are the culprits most of the time.  These can become disengaged from the black plastic connector and allow the wire to loose connection to the regulator.  I'll give the connector some TLC and make sure the blade connectors are clean and well engaged to the plastic connector.  

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Another point I should have mentioned is that if the connection is bad the connector itself gets hot and so the spring tension of the connector onto the spade lug gets lost.

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Wow thanks a lot to all of you who took the time to offer suggestions. I will check out the possible remedies that were outlined and see what happens. Dick sounds like he has the exact same thing as I do so I will anxiously await his testing and reply.

Thanks again,

I will follow up when I know something more.

I didn't realize that others were having the same problems.

Larry

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4 hours ago, Flying Bozo said:

Well Tom that is interesting. The problem has not been an issue because I have not had any long trips ans so was not concerned too much. However, I have to fly it to Tulsa this weekend from here in Arizona so wanted to see what I could do.

Your customer's problem is interesting because it sounds the same as mine. It does charge OK. So now is that customer still having the same problem or is it finally fixed?

Thanks for the comments.

Larry

He sold the airplane.

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All good info here but I'm still wondering why the light goes out and my volt meter always shows good charge, even when the light is on?  Also, wondering why once the light is out, it stays out during my flights?  I''d think if there was a problem with poor connection at the regulator, this would be intermittent during flight or at least would reoccur after stopping and starting during shutdowns along the way.  Just thinking out loud and part of me still suspects the regulator due to it's poor history.  Need to pull the connector off of the regulator and clean and examine the blade connectors.

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15 hours ago, Flying Bozo said:

Hope someone has an idea as to this problem. Alternator light stays lit for about 3 to 5 minutes after start and then goes out. All the time that the light is on the voltage is right up in the 13.7 volts. So it is charging. Then after it goes out it does not come on again. Next time out from cold start it does it all over again but not if I just make a stop like for something to eat it is OK and does not do that stay on thing. can anyone shed any light on this issue. We have re-tightened all the grounds.

Larry

Is this in a CTLSi?

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 Eric, this is a 2006 CTSW like the one Dick Harrison has. Dick thanks for checking it out. You have the exact same problem to a tee that I have..I mean exactly. So I called Lockwood this morning and talked to Dean. Very helpful but the final decision was that it is a mystery. If regulator was bad then it would not be something that would only happen under those particular circumstances. He suggested a wire to the light might be frayed and grounding out but we sort of dismissed that since it would also do so later in the flight or later in the day

So as of this minute, no conclusions. He thought it it is charging then the regulator is OK so the battery is getting charges so probably keep flying it. He did also suggest that it might be good to reset the 6 pin spade terminal on the regulator, although he sort of dismissed that since it only happens once after first start up.

Maybe a piece of black electrical tape over the light HUH??? LOL

Larry

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Hi Procharger, and thanks for the comment. I guess this is one of those things isn't it"?  It is comforting to hear that your problem has been going on for such a long time and at leaset gives me some peace of mind. After all the comments and especially Dick's and yours I am going to ignore it unless the problem changes.

So thanks for weighing in, all this has been very helpful.

Larry

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ditto here... (ctsw2006)  random light (not often) during warm up, unless rpm's are higher.  Never seems to happen later in day

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Larry, Tim in his post above mentioned higher rpm's will extinguish the light on his CTSW.  I recall taxiing with higher rpm's doesn't turn my light off.  Regardless of engine speeds, it seems my plane will, 7 or 8 out of 10 times, keep the light on for 5 minutes or so on cold starts.  How about you?  If you increase engine rpm does your light go out?  I'm not sure if I've ever run my engine up to the 4,000 rpm which the test procedure Corey posted recommends.  This is because the light comes on only during warm up and Rotax recommends keeping rpm's in the 2,400 range during this time.  Once the engine has warmed up and I'm able to increase rpm's, the light has turned off.  I also recall  getting a "light on" condition when starting much later in the day after an early in the day start.  This later in the day start would mean the engine and engine components have cooled down.  Wondering if this condition might happen when the regulator is cool and doesn't happen after the regulator has heated up by it's internal circuitry combined with engine heat?  If not all CT aircraft exhibit this, perhaps some regulators might be more sensitive to temperature than others?   Based on responses to this thread, the "light on" condition does not appear to be an isolated condition.  This appears to be a condition which is  noticed by a more than just a few of us but none of us seem to ever have had any problem with low charging voltage.

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