MAVROS

Hi all,
I recently had a regulator failure resulting in a crash of my practise plane Omose 70.
I was using an LRP LIPO battery with an LRP HEAVY DUTY 10 amp reulator to power 5 FUTABA 3050 DIGITAL SERVOS.

Our local electronic expert suggested that the Servos may have drawn too much power for the reulator and this may have caused the crash.

The regulator was working inermidently on the bench after the crash. The battery was fully charged and no signs of failure. Slight dischage after only 3 minutes of flight.

My local hobby shop strongly suggested that I change batteries to the new LI FE Which eliminates the need for a regulator as they are 6.6V

YOUR EXPERT ADVISE WILL BE GREATLY APPRECIATED

THJANK U IN ADVANCE

MAVROS

AUSTRALIA

twoturnspin

I agree with getting rid of regulators, just one more thing to go wrong. However, rather than switching to LiFe maybe switch to HV servos and run everything direct on 2S LiPo that's my plan for my next plane.

onewasp

I have run A123 cells since 2006 . No regulator !

I wouldn't consider anything other than BRANDED A123 cells . BRANDED ??? You betcha there IS a difference.
I use 2300mah in the two meter and up planes and am switching to the 1100 cells for my 500 sq.in. electrics.
A pack of 2300mah cells all up weighs 135 grams. The 1100's are approximately 80 grams (I'm putting these together at this moment

The chargers I use are FMA Multi 4 and the FMA10S.

You'll NEVER go back !!!!

rcacro

The LiFe battery will be an excellent choice and as you know , a regulator will not be required. These are starting to be the popular choice for high performance models.

John

Dave Harmon

Regulators do more than lower the voltage to the radio.
They hold the voltage to the radio and servos steady as the battery is discharged...there is no servo performance degradation or speed loss as the battery discharges unless the battery voltage is allowed to drop below the regulation voltage point.

Alfonso Garcia

Dear Mavros;

I was using LRP 5 amp regulator in my Prestige F3A models the last 3 years without any problem. I use two regulator plugged in receiver different channel and all is perfect. I use two batteries in all my bigger than 46 size planes. Also my club F3A team mate use same LRP regulator but only one in his Wind S Pro. I do not feel it is need 10A regulator for this size of model then I never test it.

Best Regards. Alfonso.

bjr_93tz

Hi Mavros, I wouldn't trust a switching regulator in ANY plane that I don't want to break. If I had to use a regulator I'd pick a linear type and run it from a 2S pack. That being said I've never had a failure with one, but I just don't trust them and never will. The next linear reg I design for my Aries with 170cdi will have 3 linear regs, 1x5A for the cdi and 2x5A (10A) for the plane.

Working intermittently on the bench makes your reg a prime candidate for the bin.

I can't comment on the 6.6v setups, Futaba say 4.8V for my digitals, so 5V is what they get.

Manufactures should have picked up their game about 5 years ago and brought out a proper range of 7.4V servos.

klhoard

My Feedback: (10)

Why kill your regulator sales AND pay for the cost of changing your manufacturing by doing that?
.
As long as the old stuff is still selling, why change?
.
I've been an A123 fan myself for the last few years. No regulator, flat discharge curve. What's not to love?
.

rcpattern

My Feedback: (45)

Regulators do unfortunately fail. I still run them as I like to get the exact same voltage from the first flight til the last, but I use Ed Alt's dual regulator setup. Very small and light and also gives me redundancy against a battery failure as I run 2 smaller packs.

Arch

bjr_93tz

Too true.

Yeah Arch, the "heart" of Ed's regs are the "heart" of mine and I think they are a brilliant little IC. How he runs his and how I run mine are a little different, but building a reg or buying a reg falls into the same category as the Scratch build or ARF debate for me

I'd still prefer 4 lumpy ni-cd's if I could get away with the weight.

MAVROS

Gday Arch,

I do like the idea of dual regulator .......could you be kind enough to post some photos of your set up

thank you kindly

MAVROS
AUSTRALIA

NJRCFLYER2

My Feedback: (42)

Ans: The switch, which is far more likely to fail than a properly designed regulator.

dreadnaut

My Feedback: (5)

I agree, and this is why I use one. It sounds like there is a short, or loose connection in your reg. I had one fail on me (on the ground, fortunately). I sent it back to the manufacturer, and he fixed me right up with a replacement. He told me he found a bad solder joint.

Jeff Boyd 2

I have used these Jaccio regs (with switch) in my last 3 planes without a problem. They seem super reliable.

http://www.centralhobbies.com/Electr...Switchhar.html

JB

rcpattern

My Feedback: (45)

I will take some pictures this evening if I remember, but you can view the setup I'm using here. http://www.tech-aero.net/ I like it because it runs off one fail-safe switch setup, so you aren't carrying multiple switches.

Ed is great to work with and his stuff has been bullet proof for me,

Arch

rcpattern

My Feedback: (45)

The Jaccio stuff works well, but do NOT run it with a YS CDI unit that also goes through the receiver. It will not handle the extra current and will get hot and shut off. I have seen it happen, and actually had it happen to me. Fortunately I was up high when it happened, the engine died and it cooled enough quickly that I regained control of the plane. Not a good feeling, especially with a borrowed airplane.

Arch

klhoard

My Feedback: (10)

Obviously aregulator salesman. . .
.
If you're that worried about it, run dual packs thru dual switches directly into your receiver.
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But then, uh oh,I'm only running ONE receiver? What if THAT fails. . . OMG. . . Gotta install another receiver. . .
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Oh no, only ONE CDI unit? Better install another backup . . . with its own separate redundant batteries (and redundant regulators too!!)
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Oops, only ONE engine? Wow, maybe see if I have room in the tail for a pusher . . . perhaps add acommon driveshaft with over-running clutches to keep the spare prop spinning. . .or maybe an electric setup for diversity . . .
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Oh no, only one set of landing gear? What if I have to land inverted?. . . .
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And then I dumb-thumbed it into the ground. . .
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OHHHH NOOOOOO!!!!
.
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(good thing I have a backup airplane. . . heheheh)
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rcpattern

My Feedback: (45)

Keith,

I have run regulators for years. I do not like the feel of planes without as they change over the course of a day. Yes the A123 stuff is better, but it is still heavier than the LiPo's. I can run dual regulators with small LiPo's for less weight than any other redundant system. Unfortunately most planes are lost due to regulator or switch failure as they are weak links. Most cheap switches aren't worth putting in a trainer. It has been a lot of years since I've seen any receivers fail (of any brand) in flight. Even on my larger stuff, I don't mind one RX, but I do like having multiple power sources.

Arch

smcharg

My Feedback: (1)

Arch,
Which one are you using?  The PLR5-DDR2?

NJRCFLYER2

My Feedback: (42)

I hate to hear about anyone losing an airplane, especially when there are some relatively simple things that can be done to avoid it due to a loss of power to the receiver & servos. It helps to understand the true characteristics of the components that you can choose from, and also how they can be configured to make an optimum setup for your needs. By optimum, I mean getting the most performance out of your receiver and servos, and at the same time have it be predictable and consistent performance, minimizing the risk of power loss in flight, minimizing weight and space, and balancing the costs involved against your tolerance for failure. Personally, I am quite intolerant about losing a model due to a preventable component failure. Because of that, I take all reasonable measures to prevent it and to also try to help others with solutions for their own use.

Anything you purchase and operate in this hobby can fail. Some items are inherently more likely to fail, such as mechanical-electrical devices (switches) vs solid state electronics (regulators). To minimize the chance of an individual failure, you can obviously buy the best quality switch and improve your chances over the bargain basement switch. You can go with redundant switches, batteries, wiring and so forth and make it better yet. The more components you have, the higher the chance of a failure, but with a properly done redundant configuration, you can improve your chances of surviving these individual failures. If you go this route, and I have before with success, then always remember that every single time you turn the switch on or off, you have shortened its life, and you are, with certainty, one click of the switch closer to a failure ocurring. There is an inrush of current when you turn it on, which erodes the switch contacts a little bit each time, and there is also an arc that will occur when you turn it off, which also erodes the contacts. And of course, metal contacts oxidize over time. As the switch contacts degrade, but before they fail completely, their electrical resistance goes up, and you start to lose a little bit of power and generate a little bit of heat in the switch, which also speeds up the degradation process. So, if you like the simplicity of using just a battery and switch, then it is advisable to replace the switch(es) periodically. You decide how often is necessary, because it will depend on the quality and rating of the switch, as well as how you use it.

You can also start with a good failsafe regulator that is several times less likely to fail than any hobby product switch, and thus minimize the chance of an individual failure. A switch failure doesn't cause loss of power to the receiver, and on top of that, a switch failure is far less likely because the switch in a failsafe regulator such as a JACCIO or Tech-Aero carries no current (zero, zip, nada) when the power is ON to the receiver and servos. You can rip the switch off the wire and the regulator stays ON, as long as those two wires don't touch each other after being ripped apart. The switch in the Tech-Aero carries about 20 microamps (20 x 10 -6 or .00002A) when OFF. The Jaccio is probably similar, i.e., there's no pitting or arcing, because the current involved is miniscule. On top of that, using them in a redundant configuration makes a catastrophic failure become only a very remote possibility. This is explained in detail here: http://d7kx18lgvr3p4.cloudfront.net/Tech-Tip%200601.pdf

Despite this, you can misapply electronic components when designing any product, including regulators for model airplanes. Misapplication examples include poor thermal design (how to dissipate heat), poor choice of components (wrong ratings for the voltage and current levels involved), poor board design (improper layout of components and interconnects, insufficient filtering/ noise decoupling) and so forth. It is also possible to misapply a well designed product, with disasterous results. That would include taking a good regulator product, but using it beyond what it is rated to do. You need good information to use even a good product, or else you just need some amount of luck. There are well known examples of regulator "failures" causing a scare, or a lost model that have been caused by the regulator doing its automatic thermal shutdown thang. You've got to get the regulator chip heated past the boiling point of water to hit thermal shutdown, specifically, the junction temperature inside the chips that I use is 125 degrees Celcius at thermal shutdown. If the model is set up to overtax the regulator like that, a number of other things have probably been done wrong as well. You know, if I twist the engine's needle valve in too far I can make the the engine cylinders get too hot as well. Luckily, its harder to screw things up with a regulator installation than it is to tune an engine wrong.

In general, I don't like switch mode BECs or regulators for model airplane applications. It's not that it can't be done, because it can. I've even used them without a problem. However, you must understand some things about a switching regulator vs. a linear regulator. Every switching regulator creates and emits its own EMI/RFI noise, which some other components in your model may or may not be susceptible to. Even a switching regulator that is "working as designed" can cause a result that appears to be a loss of power, when it may in fact have caused a loss of communications with the receiver instead. How much noise the switching regulator emits within its own circuitry is not even the total picture. Since a switching regulator may operate at several hundred kHz, what it effectively does is turn your battery and switch wiring into a broadcast antenna. That is because it will turn off and on at that several hundred kHz rate , generally with very sharp rise times being introduced into what would otherwise be a nice, quiet DC path from the battery through the receiver power bus. So, you end up with not only a few hundred kHz being generated, but all of the higher frequency harmonics that exist in every sharp little pulse of power in the wiring that supplies the switching regualtor, all the way from the battery, through the switch, through the receiver power bus and into the switching regulator. Not really what you want. But, the good part is that when everything does work, it makes more efficient use of the battery capacity than a (completely quiet) linear regulator will.

I hope this helps.

cdodom

I have a question guys. what would happen if you had a 2 cell lipo plugged into a Duralite digi switch that has a regulator built into the switch that regs the voltage down to 5.7 volts and then from the switch you have a Jaccio 6v reg to the receiver? Would that cause some type of failure or any type of interference even on 2.4?

sorry if this is a dumb question.

Chris

NJRCFLYER2

My Feedback: (42)

Chris:
That doesn't sound like a good configuration. From what I understand, you would have two regulators in series with each other, which basically makes a catastrophic failure more likely. In other words, you have whatever the chance of failure is for product A added to the chance of failure for product B, and in no case will the one that is still capable of working result in delivering useful power to the receiver and servos if the other one fails. The regulators must be in parallel for that to work properly.

Now, the other thing about that series configuration is, that even when both products are working, the Jaccio isn't doing anything useful. That is because it can't. That's because the Digiswitch has already brought the voltage down to 5.7V, which is below what the Jaccio is set to. The result will be that the output of the Jaccio will be something like 5.5, maybe 5.6V under a light load. It will be operating in dropout mode, where it cannot attain the output level it wants to, because the input is too low.

So really, if you want a redundant config you want a pair of the same, or at least similar regulators. Ideally they would be set to the same voltage, and each have its own small LiPo pack, but they could run off of one. I recommend two, so if you were carrying a single 1000mAh pack, go with a pair of 480's for example. Suggest that you take a look at this Technote, which explains and diagrams this in more detail.

http://d7kx18lgvr3p4.cloudfront.net/Tech-Tip%200601.pdf

Let me know if I can help answer anything more.

rcpattern

My Feedback: (45)

Yes, thats the one...

Arch

bjr_93tz

I know when I designed my reg for the CDI I though long and hard about making it failsafe ON and guess what I decided...No Way!!!

In this particular application I wanted to be sure that if the switch did fail (presuming it failed open), then the motor would stop. I'd much rather be stuffing around tryin to start something that didn't have power, then to be priming it up thinking that it's off. That being said I still have to get around to installing some LED indication to positively confirm if the cdi is powered up or not.

Ed is right, there's alot in the designs of regs and the advantages and disadvantages of both types. The IMAC guys didn't really have some of the problems we have because they just bought whopping great big heat sunk linear regs and didn't give a hoot about the weight, and they have plenty of free air to dump the heat into.

Pushing the limits of a 5 or 10A reg in a confined space is really dancing on the minefield.

NJRCFLYER2

My Feedback: (42)

A modern 2M Pattern application does not have to be that big of a problem for a linear regulator to run cool, even if adding a CDI power draw into the mix. I'll say this much, there were many consious thermal design decisions involved in the ratings, shape and placement of things on the PLR5. My friends and I fly what I make, and let's just say that I don't want to let any of us down.