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HelicopterMain Discussion › Align bl815h and bl855h... trust??
06-16-2017 08:11 PM  4 months agoPost 1
KingCobra Heli

rrApprentice

MA-USA

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Ok I have to be honest. I've delayed building this machine (Trex700L TOP) because of all of the issues I've read and was disappointed and untrusting about the reliability of these expensive servos I've just bought.

I have decided to just use them. I am going to use a CC 20A BEC Pro set at 7v even. I've read quite mixed results on these. Many have reported failure due to voltage others report hogwash (keeping it clean)

What's the general feelings on this?

Thanks

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06-16-2017 09:15 PM  4 months agoPost 2
Aswick3

rrNovice

Ct 06710

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I can't tell you the answer because I don't know myself, however I'm in the same boat as you bc I'm debating whether I should get one myself for my build or not.
Interested to read on..

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06-17-2017 02:06 AM  4 months agoPost 3
trex craz

rrNovice

Ontario canada

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Align servos

Hi ! I have been flying my trex 700l top for 2 years now without any problems, they're very smooth and powerful, I also have another set on my trex 800 and they are the same , it seems like from what I read , they're either work or not right from beginning. By the way I also use 2 s lipo directly . Just my 2 cents worth.

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06-17-2017 03:25 AM  4 months agoPost 4
S.Dykes

rrApprentice

Wesley Chapel, FL - USA

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I like them. I have been using a set for over 600 flights on 7.4.
I am putting another set in service as soon as the weather is good enough to fly.
Very quiet servos as well.

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06-17-2017 03:31 AM  4 months agoPost 5
EEngineer

rrProfessor

TX

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Don't know about the Align servos....been using MKS brushless servos here...

With regards to the CC 20A BEC Pro, if I had one, I'd take a look at it on my Oscope for you....

Just to see what can be seen, such as it's voltage undershoot characteristics and any signals in the 10 - 40KHz range that might interfere with your FBL controller's MEMS gyros.

Wish I could be of more help.

Logo 600SXs, 700XX, 800XX

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06-17-2017 06:03 AM  4 months agoPost 6
KingCobra Heli

rrApprentice

MA-USA

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EEngineer, I'm sad to say that you've just went way over my head. I don't have a big understanding of electronics.

Please explain, are the CC 20A BEC Pro problematic? I've been lead to believe they are a good product.

Is there a preferred setup? If it were nitro I'd run an rx pack. I plan on ordering a 123 Life rx pack for my nitro helis soon.

I only have one set of MKS (wish I had more) and they are awesome for sure. Only because I bought them 2nd hand NIB still sealed at a discounted price.

Sadly I just had a JR8717 completely go dead. I never ran it actually. I bought it from a guy on here that said it had just got back from Horizon with a clean bill of heath. I bench tested it when I got it and put it in a heli and went to set it up and nothing. I never would have guessed a JR would fail like that.

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06-17-2017 03:27 PM  4 months agoPost 7
EEngineer

rrProfessor

TX

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"Please explain, are the CC 20A BEC Pro problematic? I've been lead to believe they are a good product."

Absolutely not....that I know of....

I will try to explain this in layman's terms, if I can...

An Oscope....and spectrum analyzer...are electronic test equipment that allows one to "see" what's going on in a very small time scale....because electronic "transient" conditions can appear/disappear very quickly....

All SBECS(switching regulators)...whether for helis...or for any electronic application....exhibit an electronic characteristic know as "voltage undershoot"....linear voltage regulators don't, but linear regulators are very inefficient when dropping voltage.

This voltage undershoot(VUS) occurs when high current is "demanded" by the electronic systems(in our case servo current, mostly) which can occur at any given instant depending upon the "flight loads" applied.

When VUS occurs, it's on the order of microseconds in time, but during this time the voltage can drop significantly.....depending on how the SBEC is designed.

As the current demand "stabilizes", the SBEC's voltage output "recovers" to it's normal output state.....and all this occurs rapidly and continuously....because the servo's current demands are constantly changing.

Still with me?.....

Now, SBECs can be either "internal" like those of Kontronik ESCs....or one can have an "external" SBEC such as yours.

Either type exhibits VUS.....and either type can have little VUS....or....in the worse case, a lot of VUS....and on some, the VUS transient time can be a few microseconds in duration.

The worse case of VUS is what we are concerned with, as that can cause havoc with the RX/FBL controller.....i.e. "brownout".

In an ideal world, an SBEC with little VUS....that lasts the least amount of time is what we would want.....the "perfect SBEC".

Of the SBECs that I have tested, the Kontronik internal SBEC has by far the least amount of VUS.....~0.5V worst case....and the time duration is less than a microsecond.

Unfortunately for us, the SBEC manufacturers never have a specification for VUS.....so the only way I know of....is to use my Oscope to characterize this VUS for the SBEC that I use.

Without testing, I would recommend.....in general...to have your SBEC output the highest voltage your system can run at.

So your SBEC's VUS will never fall "below" the "brownout" threshold....

SBECs also exhibit another characteristic....due to the fact that it uses electronic "switching" to perform it's voltage dropping function.

One must use a spectrum analyzer to "see" what switching signals are present.

A spectrum analyzer displays electronic characteristics in the "frequency domain", rather than in the "time domain" like an Oscope does.

Some SBECs generate signals in the range of 10-50Khz....such as Kontronik SBECs. For this reason, Kontronik INSISTS that one must use the "toroids" on the cables for powering your electronic systems.

The 10-50 KHz signals of sufficient amplitude can cause havoc with the FBL controller's MEMS gyros....by interfering with the MEMS gyro's internal oscillators.

The "toroids" greatly diminish the signal amplitude of these SBEC signals....thus preventing such MEMS gyro interference....

The effect of the "toroids" is easily seen by using a spectrum analyzer.....

Like VUS, without testing, you can't make an accurate judgment as to whether toroids are needed or not.

So, my recommendation is.....that if the SBEC manufacturer says to use "toroids".....do it....period.

BTW, I've designed my own SBECs....so that's how I know of this "stuff"....

Hope this helps....

Logo 600SXs, 700XX, 800XX

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06-17-2017 03:52 PM  4 months agoPost 8
JuanRodriguez

rrProfessor

The Villages, Florida

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What would happen if you were to wrap a coil around it to induce a magnetic field ?? Would it be more efficient??? LOL !

Been there, done that and old enough to know better.....

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06-17-2017 04:18 PM  4 months agoPost 9
EEngineer

rrProfessor

TX

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In a word.....no....

Logo 600SXs, 700XX, 800XX

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06-17-2017 04:35 PM  4 months agoPost 10
EEngineer

rrProfessor

TX

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But, all joking aside, the "electrolyte" in electrolytic capacitors does not function properly in temps. below freezing.....

So, don't freeze your ESC or SBEC....

Logo 600SXs, 700XX, 800XX

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06-17-2017 05:10 PM  4 months agoPost 11
Doublah

rrVeteran

USA

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I have been running the Castle Creations 20A BEC for over a year on my 550 and 700 with absolutely no issues. Running them at 7.4 volts.

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06-17-2017 09:55 PM  4 months agoPost 12
Pistol Pete

rrProfessor

Seffner, FL

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EE post a video or link from any you have tested.

~~Enjoying the hobby one flight at a time~~

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06-17-2017 10:44 PM  4 months agoPost 13
EEngineer

rrProfessor

TX

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I don't make videos when I'm testing....sorry...in fact, I've never made a video of anything...

I've tested some Align SBECs, my SBECs, Kontronik Jive 80HV and Kosmik SBECs....

Using a Picoscope, 250MHz, 1Gs/sec Oscope/Spectrum analyzer....with test jig to impose a variety of currents using Ohmite power resistors that can be switched in.

With regards to my own SBECs, they are tested over a temp. range from below 0 deg. F(freezer) to +150deg. F(oven) using currents up to the max. current output...although all parts used are rated from -25 deg. C to +75 deg. C.....the smallest rated for 6A continuous(8A burst), +5V/+6V jumper selectable output...suitable for 450 sized helis.

The largest has 12A max. for cyclic, 6A max for anything else(dual regulator). Output voltage for cyclic, jumper selectable for +5/+6/+7.4V and the other regulator +5/+6V selectable.

But the voltage ranges can be customized.

I don't buy SBECs just to test them....I test what I fly only....

The test procedure can be applied to any SBECs...

FWIW

Logo 600SXs, 700XX, 800XX

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06-17-2017 11:02 PM  4 months agoPost 14
ticedoff8

rrKey Veteran

Morgan Hill, CA. USA

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The original question about the Align BLS855H and BLS815H:
I was worried about this when I bought them.
The ones I bought have batch numbers on the bottoms of the cases. I was told "... this is important".

I use them on my Trex 700N and Trex 600N
Maybe 300 flight total between then two helis and they have been 100% trouble free.

I use BK Servos BL-8002HV on my Trex 600E Pro with the CC BEC Pro 20.
The CC BEC Pro 20 has been trouble free and no problems.
I power the BEC with the 6S pack (rear set) on my 12S flight pack

The only problems I ever had with the CC BEC Pro 20 was when I used them on my TT Raptor 90 SE/3D.
The BEC's output lead's solder joint failed on the PC board and I lost flight-pack power. It was ugly.

However, I now consider a backup power system mandatory.
Perfect Regulators makes one for $55
But, I own 4 OptiPower Ultra-Guard 430 systems and all my helis have them.

Believe 1/2 of what you see and none of what you hear.
Fake News will be the downfall of our Republic!

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06-17-2017 11:10 PM  4 months agoPost 15
EEngineer

rrProfessor

TX

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Have never used Align servos, so I can't speak about them.

Now, soldering is one thing I know....

On my SBECs, my input leads are strain relieved at the PCB to prevent such an occurrence.....because that can indeed cause problems.

The output connectors for the 450 sized SBEC are dual lead connectors.

I forgot to add that my PCBs are 4-layered for the 450 size....and 6-layered for the 12A/6A dual regulator SBECs.

And the SBECs switching signals have been measured at ~470-500 KHz....which is far outside the range of MEMS gyro's internal oscillators....so toroids are unnecessary.

Logo 600SXs, 700XX, 800XX

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06-18-2017 03:45 AM  4 months agoPost 16
Dr.Ben

rrMaster

Richmond, VA, USA

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Get a Western Robotics BEC, such as a Hercules or Super Hercules. You'll be hard pressed to find a negative report on one. No limitations or "suggestions" for powering from only 6S from a 12S set up, either.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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06-18-2017 03:57 AM  4 months agoPost 17
EEngineer

rrProfessor

TX

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Western Robotics used to make modems and such....

I wonder how they got into making SBECs for helis?

Logo 600SXs, 700XX, 800XX

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06-18-2017 04:02 AM  4 months agoPost 18
Dr.Ben

rrMaster

Richmond, VA, USA

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Canadian company?

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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06-18-2017 04:05 AM  4 months agoPost 19
EEngineer

rrProfessor

TX

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A different company than the one that made modems?

When the old style modems became obsolete?

Never mind...it's USRobotics that made modems...different company.

Logo 600SXs, 700XX, 800XX

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06-19-2017 12:52 PM  4 months agoPost 20
Richardmid1

rrProfessor

Leeds, England

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There are ways to be more gentle on servos and running lower voltage is one but you could also run them on lower frame rates, lower gains, make sure your servo arms aren't excessively long and make sure everything is free and smooth with no binding.

Obviously the more servos that are sold the more problems you will hear about. There are A LOT of Align servos out there.

60% of the time, it works every time!

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HelicopterMain Discussion › Align bl815h and bl855h... trust??
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