Wattflyer RC Network: RC Universe :: RCU Magazine :: RCU Forums :: RCU Classifieds :: RCU User Reviews :: RCU YouTube
Home Who's Online Calendar Today's Posts RealTime Post Spy Mark Forums Read
Go Back   WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > General Electric Discussions
Register Members List Wattflyer Extras Articles Search Today's Posts Mark Forums Read Social Groups

General Electric Discussions Talk about topics related to e-powered RC flying

Thank you for your support (hide ads)
Reply
 
Thread Tools Display Modes
Old 12-27-2016, 10:48 PM   #1
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default How do you check for brown outs?

Sup peeps

I recently replaced the rudder and elevator servos (pkz1080) on my PZ Sport cub s2 with dsv130m servos that are slightly bigger, digital and have metal gears.

My concern is the stock esc not being powerful enough to support these servos plus a flap servo soon to come. While testing this setup on the bench, everything seems to work properly but i dont know if a brown out should occur immediately or would it happen 5 min into its flight.

My question is, would a bad inefficiently powered setup cause a brown out immediately or would i have to let the setup run and warm up for awhile?
FoxProGT is offline  
  Reply With Quote
Old 12-28-2016, 12:28 AM   #2
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by FoxProGT View Post
My question is, would a bad inefficiently powered setup cause a brown out immediately or would i have to let the setup run and warm up for awhile?
This raises the first Red Flag. How cold are the batteries. Any Lithium Ion battery does piss poor if cold. They cannot supply rated current if cold. You want them 80 to 90 degrees.

Brown ot are not much of a concern if your equipment is matched up and batteries are in good shape. Using to small of a battery, one with to low of a C-Rating, or weak battery will certainly cause problems but sho wup as slugggish motor response.

One known issue for some HH plane models is the ESC BEC is pushed to the limits and undersized to shave pennies off manufacture cost. Servos are not the cause of Brownouts. That is a function of battery and improperly sized equipment design.
dereckbc is offline  
  Reply With Quote
Old 12-28-2016, 12:57 AM   #3
dahawk
Super Contributor
 
dahawk's Avatar
 
Join Date: Jul 2011
Location: Keller, TX
Posts: 4,853
View dahawk's Gallery6
Thanked 279 Times in 273 Posts
Club: 114th RC Aero Squadron
iTrader: (0)
Friends: (21)
Default

Setup fail safe so if you have a brown out, the plane will be in the orientation when the rx was last bound.
dahawk is offline  
  Reply With Quote
Old 12-28-2016, 01:44 AM   #4
Wildflyer
Past President of PSSF
 
Wildflyer's Avatar
 
Join Date: Sep 2009
Location: Lacey WA, 1 mile E of Mushroom Corner
Posts: 1,626
Thanked 166 Times in 161 Posts
Club: Puget Sound Silent Flyers -PSSF & Thurston County Miniature Aircraft Association - TCMAA
iTrader: (3)
Friends: (8)
Default

I take one of my good digital multimeters, monitor the voltage delivered to the system by the ESC. Now operate all controls at the same time and watch for a drop in voltage. Then I load the servos by gently trying to restrict movement, and see if the voltage drops even further.

I have had planes act a little jumpy or strange, yet the only way I could see the voltage drop was with my oscilloscope. added a large capacitor and the problem was gone.

A 10 amp UBEC installed would stop any problems before they come up.

Oddly enough it seems the true Spektrum Rx's have the most problems with brown out, Many of the other brands of compatible Rx's seem to be able to operate at lower voltages, or have super quick rebinding.

Many of the companies seem to rate the BEC side of an ESC rather generously, while in fact they may be only able to put out the rated current while operating with a 2 cell battery.
A 3 cell battery is actually harder on the BEC side of the speed control, because the unit has more excess voltage and power to get rid of. A switching type BEC is much better in this regard.

Dave R, Proud PGR rider.
http://www.pugetsoundsilentflyers.org/
When you have flying skills like mine,
You become a master at repair.
Wildflyer is offline  
  Reply With Quote
Old 12-28-2016, 05:17 AM   #5
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

I should clarify that when i asked if the esc would be powerful enough to supply power to the receiver/servos, i ment to say the bec. Iv read that digital servos require more amperage then analog servos so im worried these 2 new servos might be to much for the stock esc/bec.

This is why i ask if a brown out should occur right away so i can see it happen on the bench and not have to fly it to find out.

Im powering this setup with a 2200 30c pack that has been well kept and works perfectly in this and a few other models.

So would the proper procedure to try an induce a brown out be to run the motor full throttle and move both sticks all around so that all servos are moving at once?
FoxProGT is offline  
  Reply With Quote
Old 12-28-2016, 07:29 PM   #6
ron_van_sommeren
homo ludens modelisticus
 
ron_van_sommeren's Avatar
 
Join Date: Jul 2005
Location: near Nijmegen, Netherlands
Posts: 872
Thanked 168 Times in 147 Posts
Club: www.rmvc-cumulus.nl
iTrader: (0)
Friends: (0)
Default

Originally Posted by FoxProGT View Post
... While testing this setup on the bench, everything seems to work properly but i dont know if a brown out should occur immediately or would it happen 5 min into its flight. ...
On the bench the servos are pretty much not stressed, no wind, they will draw hardly any current. Bench test only to check wiring and binding of controls.


The higher the power-pack voltage, the fewer servo's a non-switching = linear BEC can handle. Switching BEC's don't have this restriction.

Battery voltage?
The higher the battery voltage, the hotter a linear BEC will get, for a given current/load/servos.
Or, in other words ...
The higher the battery voltage, the lower the current a linear BEC can supply. In depth:

ron_van_sommeren is offline  
  Reply With Quote
Old 12-29-2016, 07:53 AM   #7
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Iv seen that video on becs. good stuff. Ill figure something out.
FoxProGT is offline  
  Reply With Quote
Old 12-29-2016, 05:28 PM   #8
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by FoxProGT View Post
Im powering this setup with a 2200 30c pack that has been well kept and works perfectly in this and a few other models.

So would the proper procedure to try an induce a brown out be to run the motor full throttle and move both sticks all around so that all servos are moving at once?
Certainly a excellent place to start, but you also have to load up servos to see the big picture. So yes running the throttle up can cause a Brown out especially if you have an undersized, poor, or failing ESC with BEC.

I will try to help you understand what is going on. It is all about Ohm's Law and one simple equation from Ohm's Law Voltage = Current x Resistance. Also expressed as V = IR. Technically a Brown Out is just IR loses or voltage drop/loss. Exactly what happens to overloaded electric utility lines. To much power demand and not enough to go around. Simple supply/demand forces at work.

Every battery has internal resistance (Ri), Wire has resistance proportional to the size and length. Connectors have resistance, another major cause of failures and Brown Outs. Ever seen a burnt connections?.

Let's stick with batteries for a moment because it is a major source of voltage loss. I have roughly 100 3S 2200 mah 30 to 60C LiPo's packs and know the Ri of every one of them at 75 degrees. Il check it after charging them. Ri goes up as temp goes down. Do not use or charge cold batteries. Great for storing them, but not discharging or charging them In fact can be dangerous. If they fell cool or cold to touch, they are cold. Luke warm is perfect. If you would not put a baby in the bath water because it is to cold or hot, then....... You can charge cool batteries, but do not charge cold or below 40 degrees. For flying you want lukewarm.

On average the internal resistance (Ri) of a 2200 mah cell = .015 Ohm's or 15 milli-Ohms. My planes ESC ranges from 40 to 60 amps. When you measure the battery open circuit voltage (OCV) on a 3s battery lets say is 12 volts nearly full charged. As you start to draw current, the battery voltage starts to drop. Increase the current, the more the voltage drops. How much voltage you ask? The formula is Battery Voltage = OCV - (Current x Resistance). So my fully charged battery of 12 volts with 50 amps of current is 12 volts - (50 amps x .015 Ohms) = 11.25 volts measured right on the battery Term Post inside the battery. We have not even accounted for the wire and connector losses between the battery Term Post and ESC yet.

With that kind of load current, your ESC heats up real fast, and that lowers EZC efficiency which makes it draw even more current from the battery which lowers the voltage some more. A vicious cycle called Regenerative.

If that were not bad enough, most ESC use a linear BEC where its Input Current = Output Current and that is not a good thing. Say your RX and servos use 5 volts and pulling 2 amps on your 3S battery. You are going into the BEC with 12 volts @ 2 amps (24 watts), and going out of the BEC with 5 volts @ 2 Amps (10 watts). What do you see wrong with this? Where is the 14 missing watts going?

It is not going anywhere. The 14 watts is being burned off as waste heat. You are throwing away 58% of your power as heat heating up the BEC and ESC . Say you are using say a 4S battery? Gets worse. Now you are burning off 20 watts as waste heat and throwing away 67% of the power going into the BEC. As the BEC heats up, it reduces output to save itself, screw your plane RX and servos.

A SBEC or Switching Battery Eliminator Circuit is a Buck Converter which means it is a Power Converter. A power Converter converts Power from one voltage to another voltage without any significant power losses like an AC transformer. Most are fairly efficient of around 90% which means if you are taking 10 watts out, you are putting in at 11 watts loosing 1 watt as waste heat. That does not necessarily mean they will not over heat because the will if you run that at maximum power and shut down to protect themselves. Check SPEC specs because there are a lot of Chi-Com BEC's posing as SBEC. Any SBEC worth having and a real one is going to be 90% or better efficient. Additionally and very important is if your max current requirement is say 3 amps. get a 5-Amp model. BEC issues eliminated.

So there is no single cause for Brown Outs. There is a laundry list of things that cause it. How do you prevent it. Educate yourself and keep your plane and most importantly batteries in good repair. Just because you think your batteries are in good shape means nothing unless you have taken the time to measure Ri or run other test to see if it really can perform under operating conditions. What is a good Ri you ask? There is no real good way to know unless the manufacture tells you or you measured and recorded it when new. You need a baseline to know what good is. Do not assume C Ratings like 30C means low Ri. It is an indicator but not useful. I made that mistake 3 years ago when I got into th ehobby and I am an electrical engineer with 40 years battery experience. All LiPo C-Rating is an arbitrary heat number the manufactures Market fools come up with and think is safe. I have 25C Gen's Ace 2200 mah packs that have 1/2 the Ri of now HK 60C Nano-Tech 2200 mah packs. Here is a number you want to know. When your new pack Ri doubles a year or two from now or whenever, time to retire it.

Additionally all components of the electrical system must be matched at worse case operating specs. When you buy a BNF and ARF planes, you can almost certainly bet the manufacture is pushing the thermal limits or exceeding then to keep and prices down, especially HH product lines made by Chi-Coms.

Ideally, but rarely implemented with Electrics, is using a separate small 2S battery and a SBEC sized 2x what is required to run the RX and Servos. Unfortunately you rarely can afford the extra weight and space required to do that. As for me and my two HH models. I upgraded the ESC they came with. After 3 years neither of my 2 HH models have any factory electronics left in them, and they have never flown better than they do now. Both had Brown Out failures caused by the ESC. All servos gears stripped and motors seized up. Well the Apprentice with SAFE RX is the only Factory component left, and it is the 2rd replacement at HH expense. I will say HH customer service is excellent and they care about their customers. If not for HH, many a folk would not be able to afford enter the hobby, so I must give HH that credit.

So a great place to start with factory models is upgrade the ESC and replace those PZ batteries with names you know and trust. Go to events where vendors come out and set up shop. Talk to the pro pilots, vendors, and anyone you look up to. Not Rocket Science, Even HK models are close bu tlike other discount suppliers push the limits using inexpensive equipment. It the plane uses say a Chi-Com 40 amp ESC with 2 amp BEC. Get a name brand model 40 amp 5 amp SBEC. When you blow a servo o rmotor, replace it with a better brand of like performance.
dereckbc is offline  
  Reply With Quote
Old 12-29-2016, 05:34 PM   #9
dahawk
Super Contributor
 
dahawk's Avatar
 
Join Date: Jul 2011
Location: Keller, TX
Posts: 4,853
View dahawk's Gallery6
Thanked 279 Times in 273 Posts
Club: 114th RC Aero Squadron
iTrader: (0)
Friends: (21)
Default

That's a great technical explanation. Thanks !
dahawk is offline  
  Reply With Quote
Old 12-29-2016, 05:51 PM   #10
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by dahawk View Post
That's a great technical explanation. Thanks !
You are welcome. I hope the OP understands.
dereckbc is offline  
  Reply With Quote
Old 12-29-2016, 09:19 PM   #11
ron_van_sommeren
homo ludens modelisticus
 
ron_van_sommeren's Avatar
 
Join Date: Jul 2005
Location: near Nijmegen, Netherlands
Posts: 872
Thanked 168 Times in 147 Posts
Club: www.rmvc-cumulus.nl
iTrader: (0)
Friends: (0)
Default

Excellent Dereck.

ron_van_sommeren is offline  
  Reply With Quote
Old 12-29-2016, 11:07 PM   #12
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by ron_van_sommeren View Post
Excellent Dereck.
Thanks, I try to help folks understand Nerd stuff.
dereckbc is offline  
  Reply With Quote
Old 12-30-2016, 01:28 AM   #13
raming
Ramin G
 
Join Date: Nov 2013
Location: Austin
Posts: 52
Thanked 5 Times in 5 Posts
Club: HCAM Austin
iTrader: (0)
Friends: (0)
Default BEC rating for Servo Loads and Operating Temperatures

Originally Posted by dereckbc View Post
Ideally, but rarely implemented with Electrics, is using a separate small 2S battery and a SBEC sized 2x what is required to run the RX and Servos. Unfortunately you rarely can afford the extra weight and space required to do that. As for me with my two HH models. I upgraded the POS ESc they come with. After 3 years neither of my 2 HH models have any factory electronics left in them and they have never flown better than they do now. Both had Brown Out failures caused by the POS ESC. All servos gears have self destructed and motors seized. Well the Apprentice with SAFE RX is the only component left and it is the 2rd replacement at HH expense. I will say HH customer service is excellent and they care about their customers. If no tfo rHH many a folk would not be able to afford enter the hobby, so I must give HH that credit.
The biggest unknowns for each Plane, in my experience, are:

1. Planes that require the user to custom match ESC/BEC, Battery and Servo's can be risky unless thorough verification of Temperatures, Voltages and Currents are performed.

2. What are the Servo's actually draw during 'normal' versus 'extreme' conditions?

For example, my HK RedEagle Hummer has four of the Hextronik HST900 9gm Micro Servos which claim 1.67 kg-cm max torque. But they don't spec how much current they draw.
When cycling all the servos on a bench, the inline meter reads a max total BEC output current of 1.55A with only a few mV drop in the 5.05V output. Seems to be OK .... but wait, this is not under the flying loads!
What would the current draw be under extreme load under 3D flying conditions? So I loaded a servo with a a 500gm Weight hanging from a 1.67cm Servo Arm and got a sustained current of about 0.7A. Extrapolating this 20% Load for 4 Servos gives a total load of 2.8A. Seems to be close to the 3A limit of the SBEC integrated with the HK Blue Series 30A ESC.

3. How hot does the ESC (and therefore BEC) get during a flight?
In my Hummer case, the ESC is mounted on the Outside so it gets only to about 35C or so after an aggressive flight. This is reassuring, particularly since the Motor/Battery/ESC combination is generating about 25 Amps on the 3S Battery at full throttle (ESC is rated for 30A continuous Duty). Some of my other models have a peak ESC temperature approaching 60C which is my upper limit of acceptable.

My Decision: This popular ESC and Servo combination in this 1.4lb 40" plane seems to be reliable (wrt lack of brownout symptoms) by user community experience. Over 50 Flights have not found any evidence of Brownouts. But! the 3Amp SBEC does not seem to have a lot of margin.

So what are the specific guidelines for configuring and/or brown-out proofing All-Electric Models? Here is my starting point for my 3S Battery Models:
1. ESC must have SBEC or Switching Battery Eliminator Circuit
2. For the smaller models get at least a 3A SBEC (definitely NOT a 2Amp). 5A for bigger models and/or those using digital servos would be better. 10A would be ideal ONLY IF there is adequate airflow as many of these high current SBEC's don't have adequate heat-sinks.
3. Full throttle load test the ESC and BEC while monitoring Power Dissipation, Voltage and Temperature. Make sure that you are not overloading the ESC since this will overheat the SBEC. Don't 'supercharge' your model by changing from a 3S to a 4S battery without carefully checking the Power, Voltage, Currents and Temperatures.
4. Check the Temperature at the HeatSink Area of the ESC just after a hard flight. Is it too hot to touch (>60C?)
5. Check the Battery-to-ESC connectors after every flight. If they feel HOT, replace them. (I had a Dean's Connector that dissipated 20W before it failed completely in mid-flight)

Trust, but Verify!
raming is offline  
  Reply With Quote
Old 12-30-2016, 11:49 PM   #14
ron_van_sommeren
homo ludens modelisticus
 
ron_van_sommeren's Avatar
 
Join Date: Jul 2005
Location: near Nijmegen, Netherlands
Posts: 872
Thanked 168 Times in 147 Posts
Club: www.rmvc-cumulus.nl
iTrader: (0)
Friends: (0)
Default

It is a good practice to have some headroom built in.
Lucien Miller (Scorpion USA) about derating motors, controllers, batteries, electronics in general:

ron_van_sommeren is offline  
  Reply With Quote
Old 01-01-2017, 04:40 AM   #15
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Thanks for the great info. I think ima ditch all my digital servos for analog if it means less amp strain on the esc. Id prefer to have reliability over precision for my flying needs.
FoxProGT is offline  
  Reply With Quote
Old 01-01-2017, 05:33 AM   #16
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by FoxProGT View Post
Thanks for the great info. I think ima ditch all my digital servos for analog if it means less amp strain on the esc. Id prefer to have reliability over precision for my flying needs.
Don't take this wrong, but that is just plain silly.

Digital servos are superior in every aspect of operation. Only downside of them, which is not really a downside, is they use slightly more power than its analog equivalent physical size and weight. However that power is not wasted, it is better utilized and put to work. The extra power is because Digital servos are a lot faster, considerably more torque, holding power, and accuracy for a given size and weight.

Your conclusion is the same as saying you are going to change out your motor to a slower less powerful one because your ESC cannot handle the motor. Now you have an under powered plane and significantly increasing your chances of a crash.

You are tossing out perfectly good servos that cost some real coins for some cheaper lower quality servos to try to fix something it will not fix. The problem is the ESC with an undersized BEC, and maybe the whole ESC is undersized. A new properly sized ESC is going to be less expensive than new Analog servos and the money you lost tossing out superior digital servos.

Sorry if that was harsh and hard to read but the truth hurts sometimes. I do not believe in PC because that would mean lying to you or worse not saying anything allowing you to do something you are going to regret.
dereckbc is offline  
  Reply With Quote
Old 01-01-2017, 08:34 AM   #17
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Originally Posted by dereckbc View Post
Don't take this wrong, but that is just plain silly.

Digital servos are superior in every aspect of operation. Only downside of them, which is not really a downside, is they use slightly more power than its analog equivalent physical size and weight. However that power is not wasted, it is better utilized and put to work. The extra power is because Digital servos are a lot faster, considerably more torque, holding power, and accuracy for a given size and weight.

Your conclusion is the same as saying you are going to change out your motor to a slower less powerful one because your ESC cannot handle the motor. Now you have an under powered plane and significantly increasing your chances of a crash.

You are tossing out perfectly good servos that cost some real coins for some cheaper lower quality servos to try to fix something it will not fix. The problem is the ESC with an undersized BEC, and maybe the whole ESC is undersized. A new properly sized ESC is going to be less expensive than new Analog servos and the money you lost tossing out superior digital servos.

Sorry if that was harsh and hard to read but the truth hurts sometimes. I do not believe in PC because that would mean lying to you or worse not saying anything allowing you to do something you are going to regret.
Oh i didn't take it the wrong way. I dont think its really that silly tho. Well i guess if all my planes had digital servos and i wanted to replace them all with analogs then yeah it might be cheaper to upgrade the esc/bec instead. In my case however, most of my planes have analog servos already and i had 2 digital servos laying around to use as a back up to replaced servos with stripped gears.

To be safe, i did some research to make sure it was ok to mix digital and analog servos and what i found out is a lot of brown outs are due to digital servos over loading a inefficient bec. This was simple to see if its ok for me to fly my sport cub with these servos or not. Yeah i can upgrade the esc but that's not what i have in hand at the moment and if i could make this repair with the spare parts i do have, then that's what i want to do.
FoxProGT is offline  
  Reply With Quote
Old 01-01-2017, 04:59 PM   #18
ron_van_sommeren
homo ludens modelisticus
 
ron_van_sommeren's Avatar
 
Join Date: Jul 2005
Location: near Nijmegen, Netherlands
Posts: 872
Thanked 168 Times in 147 Posts
Club: www.rmvc-cumulus.nl
iTrader: (0)
Friends: (0)
Default

You could do it the old fashioned way and use a receiver battery. (Far) superior to (S)BECs.
If you have the space of course.

ron_van_sommeren is offline  
  Reply With Quote
Old 01-02-2017, 10:53 AM   #19
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Originally Posted by ron_van_sommeren View Post
You could do it the old fashioned way and use a receiver battery. (Far) superior to (S)BECs.
If you have the space of course.
Thats defiantly one of the options im considering.
FoxProGT is offline  
  Reply With Quote
Old 01-04-2017, 12:33 PM   #20
JetPlaneFlyer
Super Contributor
 
JetPlaneFlyer's Avatar
 
Join Date: Mar 2009
Location: Aberdeen, Scotland
Posts: 6,030
Thanked 617 Times in 581 Posts
Awards Showcase

125mph Speed Demon  5kW  Outstanding Contributor Award  1kW 
iTrader: (0)
Friends: (10)
Default

Simple test:

With plane secured stir the sticks furiously so as to get all the servos moving as fast as possible. Keep this up for a little while (say 30 seconds). if the servos keep responding throughout then the BEC is coping. If the servos 'freeze' momentarily then you have just had a brownout and you need an upgraded BEC.

Some will probably say that this isn't a 'fool proof' test because the control surfaces are not under aerodynamic load but in my experience it works well enough.
JetPlaneFlyer is offline  
  Reply With Quote
Old 01-04-2017, 02:40 PM   #21
dereckbc
Super Contributor
 
Join Date: Jun 2013
Posts: 1,031
Thanked 58 Times in 56 Posts
iTrader: (0)
Friends: (3)
Default

Originally Posted by JetPlaneFlyer View Post
Some will probably say that this isn't a 'fool proof' test because the control surfaces are not under aerodynamic load but in my experience it works well enough.
I don't think you would say fool proof either simply because you are not putting max smoke load. However does not mean it is not a good test because if the Servos freeze, you gotta he!! of a problem on your hands and need to toss the ESC/BEC in the garbage.
dereckbc is offline  
  Reply With Quote
Old 01-04-2017, 10:21 PM   #22
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Originally Posted by JetPlaneFlyer View Post
Simple test:

With plane secured stir the sticks furiously so as to get all the servos moving as fast as possible. Keep this up for a little while (say 30 seconds). if the servos keep responding throughout then the BEC is coping. If the servos 'freeze' momentarily then you have just had a brownout and you need an upgraded BEC.

Great. So far my setup passes this test and i got one flight in with no problems so i think im ok.

Thanks for all the helpful input everyone.
FoxProGT is offline  
  Reply With Quote
Old 01-05-2017, 02:48 AM   #23
Stevephoon
Super Contributor
 
Stevephoon's Avatar
 
Join Date: Aug 2005
Location: White Lake, MI
Posts: 1,123
View Stevephoon's Gallery70
Thanked 121 Times in 119 Posts
Club: United Flying Organization
iTrader: (1)
Friends: (8)
Default

Hey, you don't live that far from me... I don't think I've seen that here on WattFlyer before...

So you think you are OK... Now keep checking the status lights on the RX after each flight. On all of my Spektrum RXs, they will flash an LED if a power outage or complete signal loss occurs. Try momentarily disconnecting the flight battery and see if your RX status light flashes after reconnecting the battery. (Can you see the RX in your plane?) This can also give you a clue if there are RX power issues.

Steve

Growing the fleet!
Stevephoon is offline  
  Reply With Quote
Old 01-05-2017, 05:16 AM   #24
FoxProGT
Member
 
Join Date: Dec 2015
Location: Troy Michigan
Posts: 87
Thanked 0 Times in 0 Posts
iTrader: (0)
Friends: (0)
Default

Originally Posted by Stevephoon View Post
Hey, you don't live that far from me... I don't think I've seen that here on WattFlyer before...

So you think you are OK... Now keep checking the status lights on the RX after each flight. On all of my Spektrum RXs, they will flash an LED if a power outage or complete signal loss occurs. Try momentarily disconnecting the flight battery and see if your RX status light flashes after reconnecting the battery. (Can you see the RX in your plane?) This can also give you a clue if there are RX power issues.

Steve
Thats right! Id have to take the wing off to get to the receiver but thats ok. Ill be keeping an eye on that.
FoxProGT is offline  
  Reply With Quote
Old 01-07-2017, 12:03 PM   #25
JetPlaneFlyer
Super Contributor
 
JetPlaneFlyer's Avatar
 
Join Date: Mar 2009
Location: Aberdeen, Scotland
Posts: 6,030
Thanked 617 Times in 581 Posts
Awards Showcase

125mph Speed Demon  5kW  Outstanding Contributor Award  1kW 
iTrader: (0)
Friends: (10)
Default

Originally Posted by dereckbc View Post
I don't think you would say fool proof either simply because you are not putting max smoke load.
Thing is that in normal flight you would never 'furiously stir the sticks' for 30 seconds.. So while the test might not simulate maximum theoretical individual servo load, the combined and sustained load I think is as much as you would ever see in normal use, short of maybe a stalled servo. FWIW some heli flybarless controllers even have a BEC test mode where they pump all the servos automatically. The current spikes that produces on the BEC is very severe.

Fortunately modern receivers re-connect after a brownout in fractions of a second, so providing the load that caused the problem is a transient then an isolated brownout shouldn't be 'fatal'... But even so i always over-spec my BEC anyway!
JetPlaneFlyer is offline  
  Reply With Quote
Reply

  WattFlyer RC Electric Flight Forums - Discuss radio control eflight > Electric R/C Airplanes > General Electric Discussions


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Always pays to check things out. Tinlid General Electric Discussions 14 07-04-2015 01:11 AM
Things to check on an arf AEAJR Beginners 8 08-13-2013 10:29 PM
Something you might want to check!!! Glacier Girl General Electric Discussions 5 04-26-2012 04:24 PM
Something else to check, your bec! Glacier Girl General Electric Discussions 6 03-11-2012 01:26 AM
User review - Dualsky LiPo Mate check it out gang! rcers Batteries & Chargers 2 12-18-2010 05:24 PM


All times are GMT +1. The time now is 09:52 PM.


Powered by: vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2005 WattfFlyer.com
RCU Eflight HQ

Charities we support Select: Yorkie Rescue  ::  Crohn's & Colitis Foundation



Page generated in 0.56882 seconds with 68 queries