Electrical Problem - Main Circuit Dead

[Steven]

This morning my 4 year old CTLS experienced some sort of electrical failure as I tried to start the engine. I flipped the main switch on and all seemed normal (right side panel came on) until I turned the ignition key to start the engine. There was a click and then everything went dead. The engine never cranked. After that everything stayed completely dead even as I flipped the main switch repeatedly off and on and also flipped all the fuses off and on. The battery is fully charged as shown by a green light on the battery minder.

 

Any ideas what this could be ? Perhaps the main switch just blew when the electrical current surged to run the starter motor ? Or could a wire have failed ? If it's simple I could try fixing it myself, although I'd prefer not to. Could it be something complicated that only an experienced CTLS mechanic could fix ? I notice that there is very little detail in the electrical diagrams in the maintenance manual.

 

The plane was fine when I flew it a days ago, so it was only idle for a short period of time before this electrical glitch occurred.

[Mike Koerner]

Hi Steven,

 

Sorry to hear of your problem. I have a couple of thoughts on this.

 

FIrst, I'm a bit concerned about the use of a Battery Minder. It's not the prescribed device for this particular battery and should be unnecessary. The battery should hold a charge for many months.

 

As to you what you should do now, the first thing - before playing with any wiring - is to determine the state of charge of the battery. The green light on the Battery Minder may be a reasonable indicator under normal circumstances, but in this case you need to measure the voltage across the terminals with a volt meter. It should be very close to 12 volts... but I think you're going to find it's a whole lot lower.

 

Mike Koerner

[CT4ME]

Providing the battery is good, step two should probably be to check all grounds. Make sure they are clean and "wrench tight".

Tim

[Steven]

Thanks very much for all the responses. It's much appreciated !

 

I will certainly check the battery and grounds although with a sudden, hard failure like this, it seems much more likely to be a main circuit fuse or bad wire problem, in my opinion (though I have no experience with electrical troubleshooting .... I'm a pilot and owner, not a mechanic). The battery was fine 3 days earlier for a flight and appeared fine when I flipped the master switch on. The hard failure occurred only after I turned the ignition switch to crank the engine (about 10 seconds after I turned on the master).

 

Just some further clarification on the battery - it's my 3rd in 4 years .... they never lasted through the winter here in the northeast. I have an outdoor tie down and typically starting in January the battery had insufficient cold cranking power to turn the engine fast enough for a start. Then by March it was typically nearly dead, so I replaced it seasonally with a new one. A trivial expense compared the cost of the plane and my monthly tie down expense of $325. I'm just north of New York City. Last autumn I got the battery minder and heating coils for the oil drum. The engine started perfectly all winter long. So I can't fault the batter minder .... it provides a ~1.5amp current drip charge .... might not be perfect for the battery, but it sure got me through the winter. I had not been using it for the past few weeks anyway and plugged it in only after the electrical failure to see whether the green indicator would come on and it did. So I really think the battery is ok.

 

I found the wiring diagrams in my owner's binder, however they look very complicated and it's difficult to understand where the myriad of fuses and switches are physically located. Unfortunately I'm rather pessimistic about my own chances for fixing this (haha) and the local maintenance director has been unwilling to have his mechanics service my plane (except "off the books" as a customer assist) due to their lack of certification in light sports planes and also due to the repeated cautious language in the maintenance manuals that states that "Task can be completed only by a responsible individual who has received Flight Design Airplane Operation Training". I had been flying the plane to Mid Island Air, about a 30 minute flight, for all servicing and inspections during the past 4 years, because they sold me the plane and have a fleet of light sport planes that they service, all Rotax, but no CT's.

 

I may have to fly in a mechanic from Woodstock, CT (Flight Design Headquarters) to troubleshoot and fix this - fortunately just a 1 hour flight away, or a 2+ hour drive. But before I do that, I'd at least like to check any fuses on the main circuit - if they're easy to find for a novice like myself - along with the master switch (which was replaced to a better one when the plane was just a year old). I hope the local mechanics are at least willing to provide me with a "customer assist - off the books" to find and replace the fuses - as they recently did to replace the front tire when it went flat.

[Steven]

Ok, I'll replace the battery as a first step in troubleshooting. I have an Odyssey PC310 here at home that's in good, but not perfect condition .... will that one suffice or should I order a new one ? I have it on the charger now and it's substantially charged, but not like new.

[Steven]

Luckily I just found that I have a digital multimeter that came with the battery minder. It's model DT830B .... my battery here at home is showing 13 volts. I'll test my plane's battery tomorrow evening ....

[Steven]

Thanks, I didn't realize there's a wire coming out of the bottom of the engine for jump starting. I'm not allowed to bring a car out to the plane, but I'll have a mechanic help me with an attempted jump start. Since I'm making the trip to the airport, is there anything else you would recommend that I can do myself ? Is it easy to get at those fuses behind the panel ? Do they lie on the main circuit ? Can they be reset manually or do they have to be replaced once they blow (fail) ? A secondary question is why they would fail ? Is the master switch itself a possible culprit ?

 

Roger - I really appreciate your expert advice on this and will be glad to compensate you for your time if you like. Just let me know !

[Runtoeat]

Steven, guys like Roger are the experts but some comments - the wire coming out of the bottom of the cowl has a main function to provide a convenient hook up for battery chargers/tenders but this wire can also be used to connect an external 12v battery to jump start the engine. If you have a separate 12v battery that is charged and of sufficient amperage to start the Rotax, this could be carried to the plane and a car would not have to be driven. As Roger states, this simple action could save you a ton of time analyzing your problem if the plane leaps to life with a good battery powering your start system.

 

Some thoughts on the battery minder or "trickle charger". There are probably almost as many ideas about what one should use as there are forum members here. My personal thoughts. I ruined my first battery by using the standard automotive "trickle charger". Standard automotive chargers or battery tenders don't provide the higher charge voltage and special cycle for charging that the AGM (absorbed glass mat) batteries require. Make sure you have the special battery tender needed by going to a good battery supplier, tell them you have a AGM battery and find out what they recommend. Personally, I use a CTEK charger and this is just left on my plane at all times I am not using it. Hook it up and walk away and forget it. It temperature compensates and is fully automatic. I believe these sell for around $55.

My link

[Steven]

Well I'll be thrilled if it's just a battery problem, but I'm pessimistic ..... though clearly it should be ruled out as a first step which I'll try to do tomorrow evening. Unfortunately I can only imagine that troubleshooting this electrical problem might be very difficult and time consuming even for an experienced CTLS mechanic. The wiring diagrams are very complex and don't provide the physical location of many fuses and switches. So it's literally going to be like "opening a can of worms" - the wires being the worms. Haha. I am very curious about the what the root cause will ultimately be found to be and am glad the failure occurred on the ground rather than in flight .... I imagine the engine would have kept running on its seperate and isolated twin circuits, but I would have lost all the avionics. I do have a hand held radio on board for backup, so would have used that to communicate with the tower at HPN, my home base.

[Tip]

My bet would be the battery. I went through 3 batteries in my 08 LS the first year. I purchased a charger from Lockwood (which I recommend) and have never had a problem since. My friend's SW wouldn't start one morning and the problem was his automotive battery tender was accidentally switched to 6 volts instead of 12. The battery charger discharged the battery to 6 volts and all he had was a buzz in the headsets. Double check that switch.

[Steven]

I'll keep my fingers crossed. I sure hope it's the battery, the main switch or something else easy to find and fix.

[Steven]

I went to the airport this evening. I expected the main circuit to be dead but to my surprise the symptoms were exactly the same as last time .... I switched the master on and the right side display came on along with the fan. I tested the flaps and those worked, seemingly at regular speed. Then I turned the ignition key, there was a click, then engine never cranked and everything went dead. It stayed dead when I flipped the master switch on and off repeatedly. So now it does seem more like a battery problem .... maybe the attempt to produce enough amps to crank the engine saps the battery of all energy .... then it recovers over many hours so it can at least light up the display again ???? I did have the battery minder back on so that may have charged it back to a bare minimum.

 

I removed the cowling and tested the battery with my multimeter. It did show 13.20 volts, but it may require very little load to generate that reading. It's not a load tester. So I tried a jump with the 2nd battery, but still everything was dead. I asked line service to give me a jump, but they didn't know how to do it without a receptical on the plane.

 

I've ordered a new battery, 2 day express delivery. Hopefully that will do the trick, although these symptoms are puzzling to me, but I have no experience to be a good judge anyway.

 

Just for kicks, I removed the lower center panel and the right side panel to check if I saw any fuses. I didn't see anything that looked like a push button fuse. The wiring diagram shows a 25amp and 30amp fuse on the main circuit but doesn't reveal where they are physically located. Even so, at this point it doesn't seem like fuse blew, since electricity got through the main circuit a second time without a reset of any fuse.

 

Thanks for all the replies. I'll provide another status update on Thursday or Friday evening once I install the new battery. That's something I've done seasonally at this time every year anyway. I have my fingers crossed !

[mocfly]

Did you check the starter?

[Steven]

At this point I'm just trying to rule in or out the battery as the root cause. A mechanic will have to take over if it's not the battery.

[Mike Koerner]

Steven,

 

I change my mind. It sounds like your battery is fine. When you turn the ignition switch too much current is going to the starter. as a result a circuit breaker opens to protect the wiring from getting too hot, melting its insulation, shorting and starting a fire.

 

I believe the master switch is the circuit breaker. I think if you push the switch in again you will find the exact same thing will happen: power will come back on until you switch the starter ON and then everything will die.

 

So the question is why is the starter drawing too much current. It appers to be shorted. Instead of the current flowing into one of the terminals on the starter, looping around inside the motor several hundred times and then coming out the other terminal; it has found a short cut. The short results in less resistance and thus more current.

 

The short may be inside the starter itself, perhaps indicating that it got too hot at some point, in which case it has to be replaced, or it may be somehwere along the wire leading to the starter. I would take a good look at the wiring, checking for spots where the insulation looks burnt or where it is chafted from vibrating against something metal.

 

If you can't see anything obvious then someone with some electrical experience and an ohm meter needs to check for shorts in the wires. He can also take a resistance reading across the starter and by compairng this to the resistance across a new starter, can tell you whether the starter motor is burned out or not.

 

I also retract my earlier comment questioning the need for a trickle charger. Please understand that my perspective in coastal Southern California is somewaht different (although it did get down to 60F a couple times this winter).

 

I would be careful though to make sure the charger is well matched to the battery, as mentioned in a previous post.

 

Mike

[Steven]

Mike,

 

Thanks for your comments. A starter short circuit sounds plausible except in one regard .... my switch was replaced from the original fuse type switch to a regular flip/flop switch about 3 years ago. The mechanic recommended the upgrade. So the mystery is, if a fuse or circuit breaker is shutting down the circuit, then how is it getting reset without my doing anything ? Are there circuit breakers that automatically reset once they cool down ??? After the failure triggerd by my turning the ignition key, the circuit was completely dead when I flipped the master switch off and on repeatedly. Then I came back a day or two later and the master switch was working again .... the right panel came on, the flaps worked, etc. All was well until I turned the ignition key to crank the engine .... then, for a second time in about 2 days, everything was again dead. And stayed dead while I was there.

 

My hope is that the battery is borderline and that the electrical demand created by turning the ignition key effectively drains it of the minimal charge it has, so then everything fails. Then it takes a day or so to sufficiently recover due to the trickle charger and the whole scenario repeats. That's my theory at this point .... although it's still a mystery that the same battery shows 13.2 volts according my voltmeter and also started the engine easily just a few days before the first failure.

 

My new battery should arrive today or tomorrow. I'll immediately install it and that will either fix the problem or point me elsewhere .....

 

Steven

[mocfly]

Steven,

Have you called anyone at FDUSA? They are really helpful and as simple a circuit as our system is they should be able to give you some pretty quick guidance.

 

Chris

[mocfly]

Steven,

Another quick way to check and see if it is in the starter would be to remove the cable going from the starter solenoid to the starter and turn the key to the start position. If the circuit doesn't go dead then my focus is a stator short in the starter. I am saying this without a print for your aircraft in front of me and no knowledge of how your upgraded switch works.

Chris

[Steven]

Unfortunately it's not a battery problem. I installed the new battery this evening and got the exact same failure. I flipped the master switch on and everything looked normal. I even turned on the avionics and everything electrical. Checked the landing light. It was very bright. Then I turned the ignition key, the engine never cranked but there was a loud click (or even a clunk) and instantly everything went dead. And stayed dead. As per past experience, the electrical system does recover over time. I don't know how long that takes, but then the scenario can be repeated.

 

I'll call Dave at FDUSA tomorrow and ask him how I should proceed. He's their new chief mechanic. As I posted previously, the local mechanics have no light sports maintenance experience and the director of maintenance has not allowed them to work on my plane. Hopefully he'll change his mind if I put him in touch with FDUSA to discuss how they should proceed. Otherwise I'll need a mechanic with the appropriate skill set and light sports certification to drive or fly in to HPN work on my plane. I don't think there'll be an easy solution which makes me a bit gloomy.

 

Does anyone have any ideas what this could be ? A short circuit related to the starter motor sounds plausible as per some prior posts. A mystery is the circuit breaker .... how does that recover by itself over time ? Anyone familier with that kind of breaker in the CTLS ?

[Steven]

Hi Roger,

 

Thanks for the tip. I will relay it to whomever will be troubleshooting this problem. It won't be me since I'm not a mechanic and the most complex task I've ever completed is replacing the battery. haha.

 

Tomorrow morning I'll try to get the director of maintenance to take on this project and will put him in contact with FDUSA if need be.

 

Thanks again for your ongoing expert commentary.

 

Steven

[Tom Baker]

One thing that concerns me is you said that your CB master switch has been replaced with a toggle switch. If the toggle is not also a CB type switch you are setting your self up for trouble. It was set up that way to protect the whole system. I doubt that it is the different switch though, unless there is a short in the wire that goes to the starter solenoid. Does the engine turn over by hand OK? If it does I would try removing the starter wire and checking things with it disconnected. If your battery voltage is dropping off in a big way when you do this then it almost has to be a short in the starting system.

[Steven]

Thanks for all the suggestions. I will relay them to the mechanic when he begins doing diagnostics, hopefully this coming week ! Disconnecting the starter wire for a test sounds like an excellent idea. One concern about the diagnostic process is that the failure happens only once and then the entire electrical system remains dead for a period of time. It then recovers, as though a circuit breaker resets itself. I don't know if that takes many minutes or hours, but it's not just a few minutes. It may hinder the diagnostic process. Any ideas of what's behind the mysterious recovery ???

 

As for the new master switch, yes I think it has a circuit breaker. I was reluctant to replace the original, but the mechanic gave me a sales pitch so I went along with it. Supposedly it's a better switch, so it must also include a breaker.

[mocfly]

Steven,

A competent mechanic should be able to look at the electrical prints on our aircraft and troubleshoot this in less than an hour. I bet your mechanic who changed the switch to something other than a stock item never made the appropriate electrical print change. This new addition or change to the electrical circuit should be the first thing relayed to the person who will be looking at your aircraft.

Chris

[Steven]

The switch was replaced about 3 years ago, so it's not a recent maintenance item, and has been functioning well thus far. Perhaps a problem has developed with the switch, but I'd guess that it's elsewhere. However I'll certainly alert the mechanic who works on this to check the switch early on in his diagnostics in case that's where the problem is.

[mocfly]

Steven,

Please keep us informed with what you find. If there is something in the switch that would be especially important to know for this group as others may try to replace stock switch

with said switch.

Good luck.

Chris