Official Voltage Regulator/BEC Thread - RC Groups
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Dec 10, 2011, 01:49 PM
Registered User
Avaldes's Avatar

Official Voltage Regulator/BEC Thread

There is some good information in the MKS servo thread, but you really have to sift thru it to get to some of the parts about voltage regulators. I don't want to give up on my LiFe batteries, so I would like to get a list of appropriate electronics that most of us could go out and buy to put in our F3X machines. One of the most referenced is the Castle Creations unit. But I seem to remember that there are others as well. The names totally escape me, lets get the list going:


What else? There has to be more.

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Dec 10, 2011, 02:59 PM
Eagle Butte User
PDX Slope Pilot's Avatar
Excellent idea Aaron! Here's the one I use with my LiFe packs:


Dec 10, 2011, 05:36 PM
Team Hello Kitty
SoaringDude's Avatar
While I'd rather not use any kind of regulator from a reliability point of view, MKS servos definitely need one. Other servos rated at 6v should also be run with one.

Since I have the equipment and experience I'll volunteer to do limit tests on regulators suggested in this thread and post results. I'll probably be buying several of the Voltron 6A linear regulators for testing. If anyone else wants their favorite brand tested, PM me and I'll send you my address, you send me a loaner, then I'll put it thru its paces. I'll return it when I'm done (whether or not it turned into a molten pile of things previously known as electrical components ).

Test Outline
Here's the list of tests and do offer suggestions (I'll update this outline until the list seems complete):

+ Thermal shutdown characteristics test -- this will verify how the regulator fails if it gets too hot i.e. fails with 0v, passes through the battery voltage, or--most likely--will reduce the output voltage and current to limit the heat.

+ Low input voltage test -- this will verify how low the input (battery) voltage can get before the regulator fails, and more importantly it will document how it fails.

+ Current load test -- this will essentially verify the manufacturer's claims and map it against our typical RC soaring needs.

+ Voltage output noise test -- this will verify how clean the output power is in the presence of typical digital servo loads. The less noise the better.

+ Regulator efficiency -- this will measure how much power the regulator circuitry itself consumes and dissipates. Less is better from a battery run time perspective. (thank you to Mike Wilson for this one)

Chris B.
Last edited by SoaringDude; Dec 11, 2011 at 03:18 PM. Reason: Changed idle current test to regulator efficiency
Dec 11, 2011, 11:32 AM
Registered User
Great idea creating this thread for us LIFE battery users. I just got a few of the Smart-Fly versions the other day, these are intended to be used AT the servo connection, NOT at the receiver, fixed 5.2 volt output, .03 ounce in weight, 3 amp current. They seem tailor made for what I was needing, since I was wanting to keep full voltage at the receiver. And a bonus, they are from the USA.
Last edited by s2000; Dec 11, 2011 at 02:02 PM.
Dec 11, 2011, 02:03 PM
Registered User


While you are at it....
I would be most interested in a measurement of BEC efficiency. That is, Output power divided by Input power at several load/current and input voltage conditions. It would be nice to be able to use the energy, that is, the Amp Hour rating times the voltage of the battery, and not throw it away as heat in the BEC.
Dec 11, 2011, 02:26 PM
Registered User
Interesting thread. I also like using LiFe's and get a bit nervous running without a regulator (despite in theory the peak voltage is less than a 5 cell NiMH).

I've used a cheepo turnigy switch mode bec from HK in a mid range dlg with zero issues, but am hesitant to trust it (or their higher amp version) in anything larger/more expensive.

My main concern is reliability. Are linear regs in theory more reliable than switching ones (thinking simpler design = less to go wrong), even if they are more inefficient and generate lots of heat? I understand that the rf noise generated by switch mode bec's isn't an issue for 2.4 users - is that right?

Also is it possible to run two regs in parallel, so if one burns up, the receiver still gets power..?
Dec 11, 2011, 03:28 PM
Team Hello Kitty
SoaringDude's Avatar
Mike Wilson: good suggestion, I just changed the idle current test to regulator efficiency instead.

areid: When you have lots more input voltage than the target regulated output, linear regs are much less efficient than switching. But our case of regulating LiFe down to safe levels is a fairly small voltage differential so a low drop out linear reg is better: its circuitry is less complex, it produces much cleaner power (i.e. less added noise), and it doesn't generate RF noise that can mess with your receiving system.

No, don't try to run any RC regs in parallel. They are not designed to work that way.

Chris B.
Dec 11, 2011, 04:24 PM
Registered User
Mark Miller's Avatar
Im not sure why the need for regulators with LiFe batteries at least with Airtronics, JR and non HV Hitec servos. I have been flying many planes of all types with this setup and never an issue.

I have been selling the Castle Creations BEC for a few years back when it was said that the Airtronics FHSS3 receivers were not compatible with the voltage. It was found by Airtronics to not be the case and they authorized their use with LiFe. A few fellows had issues with the BEC and stopped using them.

I have heard of issues with MKS servos with this voltage so I'd just use a servo that works instead of regulating the voltage lower.

Dec 11, 2011, 04:34 PM
Registered User
Mark, my interest in regulators is because I have MKS servos in the tip ailerons of a rather large scale sailplane, MKS is quite emphatic about not going over voltage, in all my other models I am unregulated and not worried, I wanted the MKS in this model because I feel they are the very best for my particuar need, (higher power and tighter and thin). Dennis
Dec 11, 2011, 05:27 PM
Registered User
Mark Miller's Avatar
That's cool Dennis. I was just curious as it seemed that about 2 years ago TD and F3x folks were using regulators but then they got dropped and now the question is back. I had a club mate who put some MKS servos in his plane with A123 2s pack and indeed at least one servo went poof, maybe more. He was doing TD with a mol die.

BTW...I have a few CC BEC's in stock if you are in need.
Dec 11, 2011, 06:27 PM
Tragic case
davidleitch's Avatar
The dualsky web site wasn't responding but this linear regulator is also worth checking out. However I don't like regulators that have their own on off switch as there is still current leakage. Much better to have an inline switch from the battery to the regulator
On the power planes my product of choice is:
and I like this product so much that I am thinking of using it in Maxa (electric) despite its size.
Dec 11, 2011, 08:47 PM
Closed Account
Some of the power pylon racing guys have been using a regulator made by Team Losi and available through Horizon. It's light, small, puts out 6V at 10 amps. Best part it is only 20.00 and is readily available.
Dec 11, 2011, 09:06 PM
Team Hello Kitty
SoaringDude's Avatar
Originally Posted by exf3bguy
Some of the power pylon racing guys have been using a regulator made by Team Losi and available through Horizon. It's light, small, puts out 6V at 10 amps. Best part it is only 20.00 and is readily available.
Only rated at 5A (specs) and doesn't look like it will work for LiFe batteries: its input voltage rated from 7.4-8.4
Dec 11, 2011, 09:30 PM
mostly gliders
liukku's Avatar
In the pictures you can see the regulators I am using currently. I also have a CC-BEC. I belive they are all very good as long as they work and I trust them all, the best I can, hmm.
They are three different systems with their advantages and disadvantages in terms of both price and function. My favorite is probably Multiplex SAFETY-SWITCH LiPo, it feels very solid. When and if you take a closer look at the label on the device, you can see that it is produced by PowerBox Systems, presumably with Multiplex's own specifications. It is, almost identical with the PowerBox's own Digi-Switch but Multiplex has been supplemented with some extra cables.

I eagerly await delivery from SoaringDude of a "Diode Voltage Reducing Circuit", which I think is the best and safest way to regulate voltage. You can read about this on SoaringsDude's blog.

Last edited by liukku; Dec 12, 2011 at 05:57 PM. Reason: additional info
Dec 11, 2011, 09:46 PM
Magicsmoke maker
Inflexo's Avatar
Hi folks - I'm going to jump in soon with more specs from my own gear that I design/manufacture here... is that permitted?

Latest unit I've put out is the PLD-BAC-ESJ3AR (3A, linear, with electronic switchjack, and voltage readout) - or would you rather I didn't post anything in here?

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