Kraton Best servo money can buy?

[Robbbbbb66]

I read the specs as 0.014 though?
Price is still insane, just to have a basher be able to turn his wheels at standstill, but not my money.

Amain specs say 0.14 :

 

[jkflow]

Yup, my bad. So it's slow and expensive, 2 strikes against bashing.

 

[21STalion]

Yup, my bad. So it's slow and expensive, 2 strikes against bashing.

Agree. Strong but too slow.

 

[rchelipiloteer]

Yeah Its .14 .014 Would Be Impossible Haha,

The Mks does feel great in the truck though!!!

 

[rchelipiloteer]

Turns out the MKS 388 Made my throttle kick in just using minimal amounts of steering, Added a cap to the rx and no more of that, but shseesh, that sucked till i got a cap in,

 

[SrC]

Turns out the MKS 388 Made my throttle kick in just using minimal amounts of steering, Added a cap to the rx and no more of that, but shseesh, that sucked till i got a cap in,

Yeah that servo is an AMP hog, if needing a Rx cap.
"Stall Amp" specs are not all that. I've had scenarios where a Rx cap did crap for me. Natha.
Was with both my Sav 1210's.
The better upgrade ESC's will usually have better BEC Amp overhead.
Just that some Servos are Amp hogs no matter what. BEC Brownouts will occur.


Edit.
Worse case, Exteme BEC Brownouts can cause loss of the Tx/Rx Signal....Carnage.

 

[rchelipiloteer]

just tested the crap out of it and zero issues great holding power!!

 

[dk10438]

Anyone have any experience on the Futaba BLS177SV? I might be able to get one for about 130 on CL and I see that these can be programmed with a 10PX so I'm a bit curious. OTOH, it's the same price as a Promodeler DS630 so debating on which one would actually be better. I already realize that I don't "need" a new servo. This is a "want" purchase to make all the electronics on my Limitless premium.

 

[dk3000]

Well Promodeler servos are outstanding so that's my vote but never had a Futaba

 

[dk10438]

Well one of the reasons why I'm interested in the futaba servo is that my Limitless has a
Futaba GYC 441 Gyro
Futaba 334 SBS (may change it out to 404 SBS)
10PX transmitter
so I'm curious how it would would all connect if I used the S.BUS2 connection. Plus, being able to program the servo and not have to adjust the subtrim for centering amongst other things.

 

[21STalion]

Well one of the reasons why I'm interested in the futaba servo is that my Limitless has a
Futaba GYC 441 Gyro
Futaba 334 SBS (may change it out to 404 SBS)
10PX transmitter
so I'm curious how it would would all connect if I used the S.BUS2 connection. Plus, being able to program the servo and not have to adjust the subtrim for centering amongst other things.

I'm using the 404 on a 10px and would like to try the gyro and a futaba servo but so far nothing seems to be breaking or wearing out anymore so it might take a while lol

 

[dk10438]

I'm using the 404 on a 10px and would like to try the gyro and a futaba servo but so far nothing seems to be breaking or wearing out anymore so it might take a while lol

no resale value with broken parts, LOL

What gyro are you using? I used to have a skyRC but upgraded to the GYC 441 and I'd have to say the Futaba is much nicer. Then again it's way more expensive....

Most likely I'll get the Futaba BLS177 not because I'm convinced that it's better than the pro modeler, but because I'm curious about programming the servo with the 10Px and what sort of adjustments can be made.

 

[SrC]

Amain specs say 0.14 : View attachment 244971

Better make sure your Servo Saver Spring/tension with is up to the task with 68 kg's.

 

[Robbbbbb66]

Better make sure your Servo Saver Spring/tension with is up to the task with 68 kg's.

Agreed.

 

[carckton driver]

we can say ass on here?
seriously though, you spent god knows how long typing a post about how BECs are bad but yet why are there at least a handful of servos from you that don't mention BEC use when theres at least as many that specifically state "not recomended for BEC use"? what about the ones that don't mention BEC use?

Hi guys, a customer pointed me to this conversation saying we'd been mentions both favorably and unfavorably, so allow me to add a little bit of details to the conversation.

To begin, SrC is 100% right, when he states we have limited experience with RC trucks. Hobbyists comprise about 8% of our business with defense and industry being our most important customers by a wide margin. As for me, I'm more of any airplane guy but I do own two T-Maxx rigs (nitro powered, old school), an X-Maxx, a TRX-4, an Infraction, plus three SCX24 so it's not like I'm a virgin.

That said, however, it's also true servos don't know in what they're being installed, e.g. whether it's a rocket, boat, truck, airplane, ordinance disposal vehicle, manipulator arm, focus assist device, laser guide, whatever. So to SrC I say this; agreed we don't know diddly about trucks compared to a ot of real experts like you, but we know a fair bit about servos - and - we have enough good customers to call on for advice to teach us about specific vehicles.

We, in turn, take this information, integrate it (meaning add to it what we know), and turn around and share it with others. Put another way, we know a bit, and we learn fast and thus, can actually provide a fair bit of help to those who own trucks. I will add this; I've looked you up on the Arrma Forum and have taken note - you - are one of those who provides a lot of help others. If you ever become a ProModeler customer, don't be surprised if I call to ask questions.

Next, to those with kind words for ProModeler, I am humbled our product is mentioned so highly. Thank you.

Regarding the Futaba CB700 - it's my opinion this is an awesome servo. To be mentioned in the same breath is an honor. As to why they state not to use a BEC? It's my opinion this is for the same reason I'm not fond of them, either. Will they work? Sure they work! Thing is, and as an engineer, what 'I' find more concerning regards;

1. how do they fail?
2. do they deliver what they say?

In reverse order, a little bit of reading is in order because we address this topic on the site, so there's no need to repeat. Examples include;

• The case against synthetic voltage
• BEC or dedicated pack?
• Bypassing the BEC

. . . and if you poke around on the site you'll find more useful information, but often within articles about other brands of products. Like X-MAXX standard servos and How to use an HV servo with a 6V radio and Will ProModeler servos work with NiCds? as well as Maxxing a servo's performance requires 8.4V, right? and there are other.

As to whether BECs deliver what they say, the real question is, under what conditions do they deliver what they say? If you poke around on the site of reputable BEC-manufacturers you'll find buried in the specs something along the lines of, 'Tested at 70°F with 15ft/s cooling breeze', or with language that indicates current output (flow) is dependent on voltage input. Yup, variable output based in variable input - hmmm.

BEC Specs
So here's the thing; your BEC may see 70°F on a cool autumn day but in the heat of summer? Nope! Moreover, that's only if it's a discrete component so what if it's built into the ESC? Then it's gonna be a lot hotter than that because speed controls get hot with operation, understand? It means the harder you run the rig, the hotter the BEC is going to get, and thus, the less current it delivers! Note I said current, not voltage. More later.

The other thing is the 15ft/s is about 10mph in terms of a cooling breeze. While maybe you see that if the rig runs without a body (unlikely because so many bits protrude into the airflow the boundary layer is distributed so essentially it's operating in stagnant air, meaning practically no cooling whatsoever). Worse, with the body installed there's less airflow than without 'and' if it's a dark color the sun heats things up even more. And ESCs with fans have them to cool the components to juice for the motor. The BEC? It's an afterthought1

So again, a BEC's not gonna give you what you think. Is it enough? We don't know. You don't either. Moreover, what if it's an East Asian import instead of a domestic product? Honestly? Isn't it more likely the reason they don't give you any BEC-scpecs is preceisely because they're not really very good, take my meaning? Moreover, if the BEC you depend on was free with the ESC (because so you didn't pay sqaut for the BEC, it was free), how good is it? Do you really think it's good? Anyway, to dive into a claim of 8A, or 10A, or whatever - but - with no specs to back it up leaves me suspicious. But it get worse.

Worse is the issue regarding how BECs can uniquely fail;

• voltage high,
• voltage low,
• voltage, high sometimes,
• voltage low sometimes.

Low isn't really a problem for the equipment (receiver and servo) unless it's too low and stops working altogether (but low voltage doesn't otherwise damage the servo or receiver). High voltage is bad juju no matter what because components may go poof and give up the ghost. But it's the sometimes-high or sometimes-low that are real buggers to diagnose. Think the servo guy should warranty the quality of the juice delivered by a 3rd party BEC? In what world is that even reasonable?

Servo motors have FETs inside. It's easy to blow them with a crawler by wanging the wheels back and forth over and over trying to dislodge the rig from a crevasse. Do it long enough and a FET (or all three) burn up. No, again, user error, not warranty. Can destroy any servo on this planet in short order doing that fool stunt. Basically, because a battery cannot possibly deliver too much voltage (enough to fry the servo) then when we see fried FETs it was either a) the customer being stupid or b) the BEC giving the servo too much juice because otherwise, the 2S-pack cant fail the FETs with too much voltage. Physics. Anyway, that kind of BEC failure is fail high (and high sometimes), remember?

So a BEC that's taking 8S and regulating it down to to 2S (call it from 30V to 8V) begins to fail something then there arethings in a servo or receiver that can go poof in the process. Lets out the magic smoke. Oops! Battery can't do that. Makes a battery as a power source better. Simple. Note, when a BEC is failing high sometimes, then how in Hell are you (or anybody) going to diagnose that? So if it fries the servo, is the servo maker on the hook for the failing BEC? Hardly fair to expect that, either. Just saying.

So a BEC, any BEC no matter how expensive, compared to chemical energy that always works (a battery) 'and' which can never be voltage too high (physics) and consists of just two cells and a lead (just 3-components meaning it's dead nuts reliable), then it's better. Cheaper too. Win-win. Remember, a BEC may have 30 components. Only one goes teats up and you begin to get problems - gremlins affecting power. Simply put, there's more to go wrong with a BEC compared to a battery. As an engineer I hate when there are more things to go wrong. Always.

Current - and - Voltage
Folks confuse the two. I'll say, the BEC doesn't deliver enough current, guy responds, but I set it to 8.4V. Two different things. Apples and oranges. I'll use a dirt-simple analogy. One that's often used with DC electricity because it works.

Ever seen a children's toy waterwheel? Little paddles on a spool. Set it in a stream and it spins like mad! Hook it up to a generator with pulleys and an o-ring and it makes enough electricity to power a light bulb. Great fun for kids. Educational. OK, so imagine this set out on the patio floor. Take a 5-gallon bucket and fill it with water. Drill a 1/4" hole in the bottom and watch it leak out. Get fancy if you like and time it. Bigger hole, drains faster, right?

However, if you make a mark exactly half-way up from the bottom (or from the top, half-way, right?) an interesting thing happens. Fill it to the top and time how long it takes until it's half empty. Now time it from from half-empty to completely empty. Same amount of water but it takes longer. Why is this? Turns out the water level creates more pressure at the bottom when the bucket is full versus when it's half-full. So here comes the analogy. Water level is like voltage and the size of the hole dictates current flow (bigger hole, the faster it empties). Ready to put this all together?

Waterwheel experiment
Back to our toy waterwheel out in the driveway (or on the back patio deck), e.g. somewhere water can spill with impunity. First, hang the bucket somewhere low enough to easily refill but high enough to place the toy waterwheel beneath it (to see it easily). Pretend we start off with a brand new bucket (no hole). So first you drill an 1/16" hole in the bottom, so it leaks out a steady pinner of a stream. Align the stream of water leaking out so the water lands squarely on the paddles. The purpose is to have the water turn the toy water wheel.

Thing is, a 1/16" diameter hole probably doesn't have the power to turn the wheel. So let's drill it out to 1/8" (so we get a stronger stream because more water is flowing). Maybe it tuns the wheel, maybe it still doesn't. So next we drill it out to 1/4" (again, in hopes this creates enough force to turn the water wheel). If that's still not enough force, then maybe drill it out to 1/2" diameter. See what we're doing? We're creating a stronger and stronger force of water using the increasing diameter of the hole to create a current flow of water draining out of the bucket to spin the wheel. Bigger hole, bucket empties faster - simple relationship.

Another word for draining the bucket is flow. The current of water 'flowing' from the bucket empties it, right? Remember I said voltage equaled level and a full bucket empties to the half-way mark more quickly than a half-full bucket empties to zero and that's voltage? Let's tie it all together.

Current - versus - voltage
The servo is the water wheel. When the stream of current is too weak to turn it, that's a current source, maybe a BEC that isn't flowing enough current to adequately power the servo. Doesn't matter if the bucket is full or half-empty (8V or 6V), the hole draining the bucket isn't large enough to power the servo, maybe delivering 3A but it needs 5A - bigger hole equale more current flow - same with DC electricity. Need a stronger source of current.

Current, in electrical terms, is measured in A (amperage, or amps). Voltage potential is measured in V (volts). The potential energy in a full bucket is greater than the potential in a half-full bucket (higher pressure, the basic reason it empties to half full faster than it goes from half-full to empty). It follows the best combination is a full bucket with the largest hole. Same ting with a power source, you want the highest voltage with the highest current flow . . . take my meaning? A 2000mAh battery rated at 10C 9common as dirt, even 20C is available easily). Anyway, that small battery pack will run a rig for hours and delivers 2.0A (same as 2000mA) x 10C = 20A (and for a 20C pack its 40A). Now do you begin to understand why a battery is better? Honestly? It's not even breaking a sweat delivering 8A to the servo when a BEC may be gasping for breath. batteries are better. Period!

Given; no matter how hard the little toy waterwheel is to get spinning, eventually you get a large enough hole in the bucket it creates a stream of water strong enough to turn it (or strong enough to wash it off the patio deck altogether), right? So if you add water to the bucket using a hose juuuust fast enough that it's always full, then that's the maximum voltage (8V) but add water to it so it stays half-full as it drains (a little bit lower rate of flow from the hose) and it's still producing water flow but slower than if it were full up (reason the same size hole drains the first half faster than the second half), that's 6V.

Both full and half-full are delivering enough current to turn the water wheel if the hole is big enough, but the full bucket's flow (same size hole) generates more pressure (higher voltage) because iot empties faster (so the wheel spins faster). Look at our servo specs. We give you data for 5V, 6V, 6.6V, 7.4V, and 8.4V and there's a current figure for each. Unlike other manufacturer's ProModeler give you enough information to make informed decisions. Put another way, information is knowledge and knowledge is power. As my Dad would say, 'Put the hay down where the goats can get it!

BECs suck
So back to the BECs, maybe they deliver enough current at the voltage you select, maybe not. Another word for maybe is sometimes. Me? I dunno but a battery always delivers more than enough current - always. And 100% of the time (always) is better than sometimes, are we, agreed? So I'll begin to wind this down with this. A BEC produces current at a voltage using a variable source (because you're constantly accelerating and decelerating the rig).

But every time you accelerate the rig, the propulsion motor puts a load on the rig's battery and the input voltage dips. Every time. No exceptions. Physics. Remember when I said a good BEC company shows you the specs and the current flow is dependent on voltage? This is what I mean, the BEC is fighting like Hell to deliver what is being asked while you're busy varying the voltaage driving your rig. Not good.

The BEC-circuit at heart functions using FETs (really fast switches) to generate electricity synthetically. It's on, or off. One or the other. On longer means 8V and on for less time makes 6V. That's how it works. on and off. Another word for this is digital because the FETs are either on or off, 1s and 0s . . . digital, you grok? A battery, on the other hand delivers chemical power and it's perfectly clean and smooth, analog.

Digital vs. analog
We see something like this in other electronics. Are you computer savvy? Would you rather have a square-wave battery back up or a sine-wave UPS? Square-waves are another way of saying digital and sine-wave is like analog and the latter costs a lot more (and higher cost almost always equates to better). Perfect analogy? Nope, but I hope you take my meaning. Here's another; what about car stereo systems, would you rather have digital amp drivers with their inherent choppiness or analog drivers that are more costly but really smooth? Same idea once again! Guys who really know a lot use vacuum tubes in their amps because of their analog delivery. Yes, vacuum tubes - like from the 1940s! Analog kicks digital's ass in many places.

Look, there are times and places when digital is better than analog, servos come to mind. Other times when it's worse - but - in terms of power for receivers and servos? An analog current source like a battery is 100% of the time better than the synthetic digital juice delivered by a BEC, no question. 100% is ever single time, remember?

Futaba
So let's circle back to Futaba, who are probably the world's premier servo manufacturer (they produce in a week about as many as we produce in a year). So they're not telling you to use a battery instead of a BEC for no good reason (and neither are we). But on the one hand you have some keyboard expert (whom by definition you only know as ButtyRocket, his handle), and he's telling you BECs are great because he's never stressed a rig enough to tell the difference. Who is ButtyRocket? What are his credentials? You don't know! But on the other hand manufacturers like Futaba are saying about servos, wait a minute fellas when it comes to BECs.

Anyway, for our part (and Futaba, too I suspect) we know it takes a real 8A to drive a servo like a DS1155. Put another way, some weak-sister BEC is almost to a certainty not up to the job. Not when there's a big load. On the workbench? Sure, the wheels steer just fine but when you're driving and then it's not cutting as hard as you expect? The answer is almost certainly insufficient current flow! Seriously, it takes a BEC with stones to pwer a big ass servo. Stones means BECs costing several thousand dollars. Military-class money, take my meaning? So are such BECs available? Sure, but how much money you got?

Don't want to take my word for it? OK, remember the article I referred you to about synthetic voltage, above? Brief article, make sure to review that one above all. Take special note how at the bottom there's one comment, and one comment only. It's by Steve Carruthers, a lead project manager at the lab, and he says . . .

When attempting to power sensitive electronics, i.e. receivers and servos directly from the propulsion battery we have had several major issues and they all revolve around the motor and controller. Several things are happening all at one time and can cause many different symptoms and makes it very difficult to diagnose the problem. The first thing that we noticed that cause a problem is the voltage spikes when loading and unloading the motor. We have seen voltage change as much as 3 to 8 volts with load and a great big spike when the load suddenly goes away. I do not have to tell you what happens to performance of most electronics with large voltage swings in short periods.

The next problem related to voltage is the continued drop in voltage and increase in current during the period of performance and the loss of power to the servos. The other problems we have encountered is the switching power supplies in BEC’s and the chopped power reaching the servos and receiver. We have had many unexplained gremlins in our systems when getting ripple in the power to our systems. Our solution is far too expensive for modelers and more complicated than most would be willing to proceed with. If there is sufficient space and allowance for an extra ounce, the best solution we have found is to use a separate power supply (battery) for the servos and receiver. That has increased our reliability many fold and reduced the overhead in both time and money.
- Project Manager, United States Naval Research Laboratory

Traxxas
Wrapping this up, let me mention how people love to hammer on Traxxas servos by saying they are poop because they fail after a while - but - there's nobody better on earth than Traxxas to take $1000 and give you an awesome toy to play with like an X-Maxx (fair's fair, they're really good at that game). But to do it means they must make compromises along the way.

The servo? It's not top drawer, nothing about the rig is, but the overall package is pretty darn good (until it gets abused). That's when you being to play the upgrade game. Thing is, their BEC-circuit is sized for a 250-300oz-in servo so when you put a +1000oz-in servo in the rig the BEC falls short. Well big whoop, is anybody surprised other than a rookie? Same thing is happening with aftermarket ESCs - the BEC? It was free. So how good do you really think the silly thing is?

Now do you better understand why reputable servo companies advise against using BECs? it's not that they don't work, because they do. And they save the manufacturer a ton of money (30¢ for the components in the circuit versus $20 for a pack). What part of saving money is mentioned along with high performance? Anything?

Bottom line? If you're gonna get off the porch and run with the big dogs, you gotta feed them something other than puppy chow!

Pots vs. Hall Effect sensors
I'll close with this; there was mention of Hall Effect sensors (as in better than potentiometers). True, but not true. What? Please review more on the subject with this brief article; About Pots vs. Hall Effect Sensors to learn more because everything fails.

Reason I get paid the big bucks is to decide the way something fails. Put another way; is one way better for the customer than another? Me? I'd rather something fail with plenty of warning, meaning a little at a time is better than all of a sudden. Like a bulb that starts to flicker occasionally gives me warning to swap it out for a new one is a whole lot better for most folks than the the bulb that just up and quits without warning, take my meaning?

In brief . . . you pays your money and you takes your choice!

 

[Cheez]

we can say ass on here?
seriously though, you spent god knows how long typing a post about how BECs are bad but yet why are there at least a handful of servos from you that don't mention BEC use when theres at least as many that specifically state "not recomended for BEC use"? what about the ones that don't mention BEC use?

You’re messing with the wrong guy.

 

[Jeremy15086]

You’re messing with the wrong guy.

... To be honest I checked out of this thread a long time ago even though I am the one who started it. I am honored to have him comment on my post. I am dying to have one of his servos someday!

 

[Megafandrew]

Lately I’ve been running stock servos until they blow then I replace. I’ve had some good luck with PowerHd lately for a budget friendly servos. I really like their R series servos they are so quiet and powerful in the right application!

 

[Jeremy15086]

I have a Reefs 555... it is great so far.

 

[carckton driver]

its a genuine question, no "messing" happening.

You’re messing with the wrong guy.

... To be honest I checked out of this thread a long time ago even though I am the one who started it. I am honored to have him comment on my post. I am dying to have one of his servos someday!