ESC optinions. What are you guys running?

[Troy003]

So im now thinking the gryphon polaris bec (10 amp max) combined with my phoenix ice 50 will be more than sufficient. what do you guys think? Again I will be running 92a+'s on cyclic and 95i on the tail, stock compass motor, ar7200bx.

Thanks,

Gryphon Polaris

■TECHNICAL SPECIFICATIONS
Input voltage : 11.1V~30V(3~7 LiPo Cells)
Output voltage : 5.6V, 6.0V, 6.8V, 7.4V Selectable
Output current : 10A(Max Peak),
5A(Continuous) @ 22.2V
7A(Continuous) @ 11.1V
Size : 9mm(H) x 15mm(W) x 34mm(L)
Weight : 7g (exc. Cables)

[RudeRebel]

Originally Posted by Troy003

So im now thinking the gryphon polaris bec (10 amp max) combined with my phoenix ice 50 will be more than sufficient. what do you guys think

I've heard good things about the gryphon polaris, particularly with the set up that you are planning. I myself don't have any experience with it so I am speaking based on what I have read from others. That being said, I am actually planning to get a Gryphon Polaris for my Gaui X3 which has a BeastX with DSMX satellite and KST DS215MGs on cyclic and tail (planning to change the tail to a proper tail servo but haven't decided which one yet). I haven't really had any issues with the DS215 on the tail, but due to the weather, I haven't really been doing anything but hovering either (small park directly across the street from my house so I sneak in a short flight here and there. I currently don't have a BEC on the X3 right now so have been taking it easy and tweaking settings.

In terms of your comment "combined with my phoenix ice 50 will be more than sufficient", you can't use both Gryphon and ice internal BEC simultaneously. Again, just based on others I've seen using the MKS servos you will be using and AR7200BX, the Gryphon should be able to handle the requirement. I wouldn't just go on my wavering recommendation, but you should do some searches. Lots of people using that BEC.

[RudeRebel]

Originally Posted by waxman

My testing was with a Pyro 750-500, kosmik esc. Brand new 12s 4400mah 60c revolectrix pack and Brand new 14s 4400mah 60c revolectrix pack. So realistically the only difference was an extra 2 cells.

I have also tested with thunder power 4400mah 65c 12s packs with similar results.

The pyro 750-50 is not a monster motor by any means and is not pushing the packs to the point where they are causing a bottle neck.

I was going to ask about batteries but it would seem that batteries shouldn't be causing any funky results. Not sure what to say, as it goes against what I've been taught, researched, experienced and seen.

Originally Posted by waxman

I am looking at getting this motor rewound, the guys that do the rewinding mention nothing about inductance they just list the resistance, less resistance more amp draw. Simple.

So any way you look at it a motor has a set resistance, the only thing that can affect the resistance is increase in temperature which is minor.

I don't have time to dig up my material on inductance at the moment, but yes, resistance plays a part in the equation, but usually unless you have some sort of issue, the internal resistance of brushless motors is so small, it is the inductance that is the major player in current of a motor. Motors that are built around wound wire and magnets are an induction motor. The ESC controls the resistance between battery and motor which controls the current, which controls the speed of the motor (among other functions). The faster the motor spins, the internal resistance increases which is what is drawing more current through the motor. So the resistance that draws the current really is the internal resistance of the motor at rest + the resistance that is changing based on inductance.

Originally Posted by waxman

we know V=IxR
so if we increase volts current must increase as well because resistance stays the same.

Ohms law, yes. But once you plug in the battery to the ESC, the voltage provided by the battery remains stable (well, technically it decreases as the battery drains). The ESC is not controlling the voltage applied, it is controlling the current being sent to the motor, and as previously mentioned as the motor spins faster, it's resistance increases through inductance which draws more current. So if you rework the equation, V/R = I, where V is static and the current changes based on the given resistance.

Originally Posted by waxman

We are talking peaks here though, a heli that can hover at 200w on 12s will need very similar amount of power to hover on 14s which as you have mentioned will be less amps.

This is what I am finding puzzling, that the higher voltage LiPo, all else being equal is not drawing less current. Are you using a governor? If so, when you set the endpoints on your radio, what was the high and low setting?

Originally Posted by waxman

So how does this relate to servos? Servos draw maximum power at stall (stationary to moving in either direction, no different to any other motor) if you do a hard stop and punch back the other way this is where the servo is going to draw large peak, the higher the load the servo has to over come to start its initial movement the more amps it will draw, also the faster you want it to move the more amps it will draw (with a servo speed is related to input voltage).

Higher voltage to your servo will make it draw higher peak amps and it will work the servo harder causing a shorter life. So like i said if you dont need to run the max voltage don't. I have run 6v servos on 2s lipos and compared the wear and tare on the gears etc and they definitely wear faster. (dont try this with just any 6v servo only some will survive) i have also run logs on HV servo being run on 6v and they draw very little and work fine and i know they will last for a very long time which is a good thing for $1000 for a set.

Agreed, the higher voltage would drive the servo motors faster, thus causing more wear on the gears. Greater care of gears would definitely mean less maintenance and less gear failures. Bit from a servo motor standpoint, more current means more heat, which causes more motor wear. Most of the cost of the servo is the motor, not the gears. This being said, good servo motors should be able to handle the current draw as most of the time the draw is very little as you have mentioned.

I'll try to dig up material and links tomorrow ... as mentioned I'm not able to at the moment. Great discussion though, and thanks for engaging in it, waxman. I do agree with you that most of us don't really need to be running our servos at high voltage. Having re-thought about my rant, servo motors are not continuously running at high speeds so the current effect on the individual servos should not be of great concern as it relates to servo motor wear. We do however need to be aware that the combined draw of all the servos, FBL, and Rx is what the BEC is gate keeping so that BEC needs to be able to handle it.

Troy003, I hope you don't mind that we've sort of derailed your thread. I do hope you are finding it informative. I made sure I replied to your last post first before doing this one

[RudeRebel]

Originally Posted by waxman

My testing was with a Pyro 750-500, kosmik esc.

Just did a quick spec check on the 750-50 motor. they rate the max motor RPM at 25,000 rpm. I realize I may be stretching here but that is a 500 kv motor so at nominal voltage, a 14S is 51.8V which means 51.8 * 500 = 25,900 RPM. At full charge the 14S is actually 58.8V, so your initial RPM is 58.8 * 500 = 29,400.

It may be worth verifying with Kontronik if a 14S battery is suitable to be used with the 750-50 motor. Normally the faster spin would mean more resistance resulting in lower current, but maybe once the motor reaches max rated RPM, it is causing a different phenomenon. Again, I'm stretching but just a thought. If my theory is correct, at 14S, the right motor for your application is the 800-48 or 750-45. These motors would still be able to run your 12S, but you will lose headspeed and/or headroom if governed.

[RudeRebel]

Originally Posted by Aeolus1

Good choice on the wr, I'm running my rjx at 7.3v.

LOL, likewise ... I was planning on running mine at 6V, but the discussion that I'm having with waxman is causing me re-evaluate what I want to do.

Sadly, I am so embroiled in solving waxman's unexpected current result using the 12S & 14S with Pyro 750-50 motor that I have not touched my Warp build, LOL. I've got all the Warp parts sitting in front of me, but can't stop looking for solutions to the puzzle.

[waxman]

As i stated before im running the same setup, same pitch, same headspeed. 2200rpm.

At 2200 rpm on the blades with the same gearing your motor can will be spinning at the same speed no matter if it is a 500kv, 1000kv or if it is run on 2 s 6s or 50s. Its a fixed ratio.


Same headspeed loads more peak power. More Amps on 14s its just the way it is.


FYI i know the the motor is rated to only 25000rpm and i have taken a lot of consideration in to my setup/gearing to make sure the motor doesn't exceed this. The thing that needs to be taken in to consideration is temperature which isnt to hot at the moment as this is relatively a mild setup. If i ran a comp version of the same motor i would have a lot more temp but even more power which is not what im chasing. The TDR can be a little fragile if you give it to much power in a aggressive manor.

[RudeRebel]

Originally Posted by waxman

As i stated before im running the same setup, same pitch, same headspeed. 2200rpm.

At 2200 rpm on the blades with the same gearing your motor can will be spinning at the same speed no matter if it is a 500kv, 1000kv or if it is run on 2 s 6s or 50s. Its a fixed ratio.


Same headspeed loads more peak power. More Amps on 14s its just the way it is.


FYI i know the the motor is rated to only 25000rpm and i have taken a lot of consideration in to my setup/gearing to make sure the motor doesn't exceed this. The thing that needs to be taken in to consideration is temperature which isnt to hot at the moment as this is relatively a mild setup. If i ran a comp version of the same motor i would have a lot more temp but even more power which is not what im chasing. The TDR can be a little fragile if you give it to much power in a aggressive manor.

hmm, well that is a problem. If you are using the same setup for 12S and 14S, expecting to get the same 2200RPM head speed, that means you too much pinion for the 14S and the only way you can control the headspeed down to 2200 RPM is through throttle. You obviously have enough teeth on the pinion for the 12S or you would not be able to attain the desired headspeed. What is your throttle setting when you are running 14S? What pinion are you using?

I can tell you with certainty that if you are using low throttle to control your headspeed instead of using the right pinion, you will definitely drive high current. When you govern to a desired headspeed, you should be targeting between 75-85% throttle. Higher doesn't give you enough headroom, and lower will drive high current. Mystery solved.

[waxman]

Yep i control headspeed via throttle % i have the biggest pinion that henseleit make on it 16t.

i currently run 2400 headspeed with 710 blades at 16 degrees of pitch with the same motor and pulling massive amounts of power. This wasn't possible at the lower voltage even if i geared it to suit the motor didn't have the power to make it work. Realistically by adding the extra 2 cells i picked up around 30%+ more power.

So i still strongly disagree that a servo will not have higher peak amps when run at a higher voltage.

[RudeRebel]

Originally Posted by waxman

Yep i control headspeed via throttle % i have the biggest pinion that henseleit make on it 16t.

i currently run 2400 headspeed with 710 blades at 16 degrees of pitch with the same motor and pulling massive amounts of power. This wasn't possible at the lower voltage even if i geared it to suit the motor didn't have the power to make it work. Realistically by adding the extra 2 cells i picked up around 30%+ more power.

Just looking out for your heli ... that TDR with your setup is quite the bird. I've seen a friend fry his ESC doing the low throttle speed control thing and another fry his whole heli doing the same. I thought you were trying to solve the high current on your Pyro, but it sounds like you've got things just the way you like it. It's not one that I would try but it's not my heli. With that pitch and power, you must be pulling some crazy 3D maneuvers. I'd love to see a video of you flying it as that is one bad a$$ setup.

Originally Posted by waxman

So i still strongly disagree that a servo will not have higher peak amps when run at a higher voltage.

Does that mean you feel the same way about the 14S-12S and your Pyro 750-50 as well? I realize you've managed to set up your heli such that 14S draws more current, but that is not the how the relationship between a motor and voltage to drive current normally works.

Anyway, I will stop now, and you can do your last rebuttal and we can give poor Troy003 his thread back.

[waxman]

Thanks for being concerned for my TDR, it's not really built for 3d way to much pitch and headspeed, and a bit heavy, its a dedicate speed heli. But i tell you what if you could fly 3d with it i would be impressed. you should see it move when you take off flick the headspeed to 2400 and then punch out with 16 degrees of pitch. I have never seen another heli move that fast from a standing start. I have a second TDR for 3d thats over 1kg lighter 1600-1800 headspeed is more than enough for this heli.

You had better get back to work and finish that warp.

Im seriously considering building a second warp to run high headspeed. I think i have enough spares to build 2 more completely lol.

[Aeolus1]

Just installed a yge 120lvk

[waxman]

Very nice

[Troy003]

Dont take offense but why a 260$ 120amp esc on this size heli? Is it for the continuous 6A/ 12amp peak bec?

Troy

[Aeolus1]

I got it from a buddy of mine, didn't want to use the bec and it was just messy with the all the wires.

This is the old one

[Troy003]

Gotcha. Well I missed UPS today so looks like I will have to wait until tomorrow to get my Warp. I need to stop looking through the Warp forums until it gets here, you guys are all making me jealous!

Troy

[waxman]

Surely a BEC that size could have a built in esc

[AlvaSpeed]

Had a Megapower HV in one.
On my new one I am running YEP 60.
Both run fine.

[CHOPPER PATROL]

I've been running my 360 since last year and have had many bizzarr instances. Just now on the bench I am noticing many brown outs where servos lock for a short time. I am running a YGE 60hv, Gryphon Polaris bec, MKS D92a on clyclics, and a 95i on the tail. VBar logging shows "RC Input of ... channel missed" on all channels (it's hard to fly with missing inputs). If I power with a receiver pack I get no glitches on the bench. Looks like I will be getting a new bec. Wish I would have solved this much sooner.

[spektrex]

I have bought a YGE 60LV and sent it in for adding a RPM sensor lead output. I just got it yesterday, the ESC now had a throttle lead and a seperate RPM lead that I intend to connect to the mini-vbar port A

Since this ESC only has a 3A continuous (5A peak) BEC, I ordered a seperate BEC. Made my choice and got a Gryphon QUASAR 75HV 10A / 20A BEC. Weight is not an issue, pricing is reasonable and I like oversized - I intend to run the scorpion motor and I have MKS servo's which tend to be a bit power hungry.

All in all I think that this thing will not drop out of the sky due to electronics failure, which feels kind of nice

[Troy003]

Ended up throwing on a CC 10 amp Bec running 6v. About 15 flights now some pretty hard and so far so good.