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Old Sep 21, 2012, 11:22 PM
I forgot my sunglasses AGAIN!!
United States, TX, San Antonio
Joined Sep 2012
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LEDs flickering during flight! Help?

Hey guys, I have a an Ares Gamma 370 with the brushless motor/esc upgrade and I decided to fill in the extra aux and gear channel on the rx with a pair of Easylights from Dimension Engineering and I noticed during my first night flight that the pair of LEDs would flicker off for just a split second, then back on. This happened once more and I decided to try to land and see what was going on. Then, the lights went out for a solid 2-3 seconds. I think my heart stopped during that time, but they miraculously came back on about 50 feet above the ground and I pulled out of the horrifying dive I had gone into. I emergency landed as quick as I could into the grass.

So anyway, does anyone know what might be the problem for them doing that? I am not sure but I believe power to the entire plane was cut off, since it dove down when the lights went off. The battery is 2s 7.4v 20c, and these lights are just supposed to be PnP - simple so I am afraid to go back out at dark until I figure this out.

TL;DR - My Easylights keep going out during flight. I have 2 of them plugged into 2 spare channels on my 6 ch rx. I am using a 2s 7.4v 20c battery. Any ideas on the problem?

Pics included if anyone has advice or can see something I am doing wrong. I am just a beginner!
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Old Sep 22, 2012, 12:01 AM
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Joined Apr 2012
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Lights

MY NIGHT VAPOR'S LIGHTS FAIL WHEN THE BATT. IS LOW. PROBLY NOT THE PROBLEM HERE... MY CESSNA'S LIGHT ARE MULTI-LINE WITH SPLITTERS AND THEY GET LOSE AND NEED TO BE ATTENDED TO EVERY NOW & THEN. YOUR PIX LOOKS LIKE THESE ARE A SINGLE LINE SO, NOT THAT PROBLEM HERE, EITHER... AT THE PLUGWIRES; ARE THE CONNECTORS ALL THE WAY IN WHEN YOU PUSH THE PLUG IN; THE METAL SLIDES THROUGH THE PLASTIC ABIT AND LEAVES A POOR CONNECTION, EVEN THOUGH IT LOOKS GOOD... LOOK AT THE WIRE AFTER PLUG'N IN.. IS THERE ANY METAL STICKING OUT OF THE PLASTIC HOUSING OF THE PLUG, ANY AT ALL MEANS SLIP-AGE.. DISCONNECT, SLIDE THE METAL CONNECTS INTO THE PLUG HOUSING BY PUSHING THE WIRES INTO THE PLUG WHILE HOLDING THE PLUG HOUSE & RE-CONNECTING WITH CARE... PEACE OUT, McWaykno...

A HANG GLIDER OF 11yrs. fly'n 2.0 & 2.6m R/C SAILPLANES, 3x HONOR STUDENT, ARRESTED 22x... GO FIGURE
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Old Sep 22, 2012, 09:19 AM
I forgot my sunglasses AGAIN!!
United States, TX, San Antonio
Joined Sep 2012
24 Posts
I figured it had to either be a power supply problem, or the receiver couldn't handle the power going through it with the lights. I have checked the connections and everything seems to be okay. Thanks for the advice, I'll keep an eye on the wires from now on in case that has to do with the issue
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Old Sep 23, 2012, 07:32 AM
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Canada, ON, Windsor
Joined Apr 2008
901 Posts
From your description the loss of lighting AND flight control means you suffered a power supply cut.

If the prop was still producing power then the battery should have had enough juice to supply the much less current hungry flight controls. If that battery was low the ESC should have cut power to the larges current consumer and still allowed for flight control for safety reasons.

However, the ESC has what should be two independent systems supplied from that pack. First is the BEC that reduces the battery voltage down to what is safe for the flight control system and accessories such as the lighting you added. Second and largest user is the ESC that takes throttle signals from the receiver and controls power to the motor.

With both mounted together a problem with one can affect the other. These units produce heat and if within a fuselage and working in stagnant air they can overhead to the point of shutdown. The ESC has what is called "Thermal Shutdown" where the unit simply cuts output to protect the electronics. If either the motor draws too much power, (producing more heat in the ESC circuitry) or a higher current draw to the flight control system causes it to reach that point it will temporarily shut down everything as you described.

Here's what I believe what really happened. Most BEC's are what is called "Power Limited" where they can only provide so much current based on input voltage. Not so important on yours, except I suspect the BEC is not that strong to begin with and the lighting pushed it close to or at the max. The second is related to working in stagnant air. Even a BEC rated at 1-3A normally gets that capability rating with the unit working in an environment of a minimum of 5MPH cooling airflow. Cut that off and the output rating would be severely compromised.

Unless you can supply the system with a higher rated BEC, even a separate unit powered from the main battery, then you will have to deal with what you have. One of the easiest would be to provide cooling air over the ESC. If also over the battery it can't hurt.
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Old Sep 25, 2012, 12:15 AM
I forgot my sunglasses AGAIN!!
United States, TX, San Antonio
Joined Sep 2012
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Thank you very much for your advice, this is exactly what I was thinking was the problem but you clearly knew what was going on. I am not too familiar with the electronics, but there is one more spot on my receiver that has the symbol "+ - s". Is that for something that might help? I would really like to keep my flying set up but the lights are just killing me. I spoke with DE's tech support and they recommend testing my channels, but I don't think that's the problem. Should I return these or is there any way I can work with them? Any ideas on how I can increase air flow? I noticed that the ESC does get quite warm after flight.
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Old Sep 25, 2012, 12:46 AM
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Joined Nov 2011
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I would drill some holes in the fuselage, not too many that it would weaken it. Or if you really wanted to get some air in there cut some small windows in and rig up a low profile air scoop (like backwards facing vents) in the windows, but not so big they would really disturb the airflow around the fuse.
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Old Sep 25, 2012, 07:47 AM
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In most receivers the + POS. (red) and - NEG (black) are common to all channels and to provide power to any device plugged into them. Only the "S" Signal pin is unique to each and is used to send position data also to anything plugged into it. These wires are normally white, yellow or orange with newer systems.

Some lighting systems will also have a signal wire as they can alter functions depending on signal to turn on landing lights, change pulse rates, etc. I imagine your basic lighting does not have anything plugged into that pin and will be limited to just the red and black.

Most should do nothing if plugged into the receiver the wrong way. This will still have the red correct, but the NEG will now be plugged into the S pin. Cannot guarantee no problems, so it would always be good to double check before powering it up by confirming it's the same as the other channels.

As for power, I would recommend a separate BEC as the easiest and best method to fix your problem. They are very inexpensive now and have some good ratings. In fact, I run all my helis this way as their flight control systems are so much more demanding. If your current ESC lists the BEC output grab one of greater current rating. If you really want to be sure a 6A should more than cover you.

They do take a bit of work to install. First would be to eliminate the current onboard BEC by popping the red lead in the plug from the ESC to the receiver and taping it back or covering it with heat shrink. The new BEC needs to be soldered to the existing battery connection so it gets power when the battery is plugged in. If you have a spare channel in the receiver simply plug the BEC output into that and go flying. If not things get a bit more complex and I would try to cover that in another post.

As for cooling there are a few little tricks we commonly use. One unobtrusive inlet is what is called a NACA duct. Have a boo here and you will see what I mean.

http://en.wikipedia.org/wiki/NACA_duct

I also included a pic of one in the nose of my Polaris. The floor of the duct has not been installed yet.

Another very easy way to make either an inlet or outlet, (or both) are plastic spoons. Simply cut the end in half, sand the edge and use the forward part as a scoop covering either an inlet or outlet hole. The second pic shows an example of that.
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Old Sep 25, 2012, 03:03 PM
I forgot my sunglasses AGAIN!!
United States, TX, San Antonio
Joined Sep 2012
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I see, thank you for your help once again. One question though: Is there any way that even if the ESC is cooled that its BEC won't be able to maintain the current? In other words, could the BEC by default be too weak to power all those things, regardless of its temperature? I just don't want to make a bunch of air flow mods if it might not fix it.
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Old Sep 25, 2012, 10:18 PM
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That's what I meant in my previous posts regarding BEC's. Most are "Power Limited" meaning as the input voltage goes up the output current will drop. AND, as I stated, those ratings are usually in a minimum 5MPH cooling airflow. Without airflow that rating is a lot lower. It may take a bit to heat up and hit thermal shutdown, but it will eventually.

NOTE 1: It does not matter what is creating the heat load. Either a high current draw in the BEC circuitry itself or the ESC shunting a lot of power to the motor can run the temp in the unit up to shutdown. That is why I asked if your ESC has a tag stating the max BEC output current.

In any case, many of the onboard BEC circuits are only rated for 1-3A feed to the flight control system. Borderline in my opinion, especially if you are running a few extra servos, (or in your case the lighting). You may have started out right at the max limit and the extra lighting you added pushed it over.

If you have digital servos the problem is exacerbated as they are current hogs by design. A normal analog servo updates position 50-60 times/second. This is the source of the "Buzz" you hear/feel if the servo arm is loaded one side or the other. In comparison digital servos update 250-300 times/second and frequently "Squeal" under load. They are far more precise, but any motor has the highest current draw on startup and when that happens within the servo up to 6 times as often you can do the math.

In fact, on larger digital servos the current draw under load or stalled can exceed 1.5A EACH! Due to that I opted for 2S LiFE packs, (A123) running through 20A Castle PRO BEC setups in my larger scale planes. Life is simpler now since a lot of the newer servos are what is called HV rated and can run directly on a 2S LiPo, (7.2V) with no longer the need for a BEC at all, but I have yet to invest in changing all mine over as it would have to be a complete systems upgrade. Unless every servo is upgraded I would still need a BEC for any of the standard voltage servos which are basically limited to 6V.

NOTE 2: By adding a stand-alone BEC you have several advantages. First is the option of getting one with a higher current output right out of the box. Second many of the "Switching" type BEC's have the option of setting the output voltage to 5 or 6V. That higher voltage is still fine and gives slightly faster servo speeds with higher torque. Switching type BEC's are also more efficient as they do not drop the battery voltage down to what your system can tolerate by dumping the excess as heat. They do just as the name suggests by switching the output ON and OFF rapidly and smooth that output with some internal buffering. From what I have found the switching circuitry is relatively easy to design. Quieting the noise on the output is where most of the work goes and where I suspect a lot of the lower end units will skimp. However, having said that most of the new units are a lot better.

Finally, by physically separating the ESC and BEC you can avoid any heat sourced from the ESC itself getting to the BEC and adding to any thermal load. All the stated advantages make the system far more reliable for little extra cost or added weight.

I forgot to mention previously that if you run a separate BEC, along with pulling the stock RED wire you MUST ensure all the BLACK wires are still connected. This will happen anyway if you simply leave them within the plugs. This gives a common ground to help eliminate electrical noise and sets a system wide common voltage reference.
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Last edited by Cougar429; Sep 25, 2012 at 10:32 PM.
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Old Sep 30, 2012, 08:25 PM
I forgot my sunglasses AGAIN!!
United States, TX, San Antonio
Joined Sep 2012
24 Posts
Well I see this is going to be more trouble than I wanted to deal with anyway. I made an air duct with the spoon like you showed and it didn't help. I am just going to return them and fly in the day time. Maybe when I move on to a different more expensive set up I will be able to make this a possibility but for now I just liked these lights because they were supposed to be 'Easy'. I really appreciate all your help it made me understand the problem much more thoroughly.
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