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  • VaNDAL_UK: ANyone FPV onver Sutton Park Birmingham?
    December 07, 2018, 12:54:30
  • steveo9007: Cheers Atom was just a thought for now as I plan on keeping it well in range until I get comfortable with controls and flying
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  • shawdreamer: meanwhile the 433mhz telem option I mentioned gives you live fixes in realtime and not "delayed texts"..... plus it doesnt cost you credit everytime you request a gps fix (btw the tags sim card also needs to have credit on it :laugh:)
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Author Topic: Quality ESC for low KV 16" props running on 6S?  (Read 177 times)

Offline stickboy

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Quality ESC for low KV 16" props running on 6S?
« on: November 28, 2018, 04:19:08 »
I am starting a new hexacopter project and was hoping to get some advice on good ESC. Currently i have a DJI NAZA V2 and purchased a Tarot T960 frame to go with the following propulsion setup running on a 6 cell batt.

Motors: Multistar 390KV 22pole
Props: 1655 Carbon Fiber
Powa: 8000mAh 6S 35C LiPo

Any recommendations on quality ESC to throw on this setup? Everything out there is targeted towards small scale race quads with high kv so I'm lost trying to find a good fit with out breaking the bank on T-Motor ESC.

I just ordered a couple different ESC to test:
(1) Lumenier 35A BLHeli_S ESC OPTO (2-6s) DSHOT
(2) Rctimer Mini ESC30A OPTO BLHeli Firmware(Oneshot125, support 2-6S)

Any thoughts on those two as options?I'm nervous using the tiny Lumeniers and not sure how much i trust RCTimer with my investment so i plan to put them through a rigorous testing on the work bench.



PS. Was running Afro 20A HV ESC on the previous quad but am looking to expand the current max of the ESC since I'm putting bigger props on.

Offline Dave@F.P.heaVen

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #1 on: November 28, 2018, 11:19:18 »
My first thought is that you are over-proping those motors. The largest they will take would be about 1455. That is off the top of my head though so please double check!

Plenty of ESC options out there but as I've said, look into your motor/prop combination first :smiley:

Offline stickboy

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #2 on: November 28, 2018, 20:36:44 »
My first thought is that you are over-proping those motors. The largest they will take would be about 1455. That is off the top of my head though so please double check!

Nah way, check out this beauty:



I've seen several others online pushing 15-18" props with these motors (the higher pole count giving them more torque). I'm having a decent amount of success myself with a pretty heavy quad AUW of 3.5kg and still getting 15 minutes of flight on 16" props and a 6S. No concerning heat to the touch either.

I guess now the question is whether the thrust/current draw trade off is worth it. I've seen somewhere that they pull 18/19ish Amps running 6S at full throttle. You've got me wondering now though.....time to do some tests. ~~

Offline ched999uk

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #3 on: November 28, 2018, 20:50:12 »
I didn't listen to sound as others in room but is that running 4S or 8S? i.e. listed as 2 x 4S.

If it is running 4S on same motors are you sure 6S will be OK?

Offline stickboy

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #4 on: November 28, 2018, 23:09:32 »
I didn't listen to sound as others in room but is that running 4S or 8S? i.e. listed as 2 x 4S.

If it is running 4S on same motors are you sure 6S will be OK?

Oooh, I see the point now. I'm pretty sure those are 4S in parallel, and I've been neglecting to consider the extra voltage.

Whelp, still gonna do some testing on different sizes over the weekend, but any down side on throwing 14" props on a 960mm hex? I'd hate to have to cut the arms down to size if I decide to go small.

Offline ched999uk

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #5 on: November 28, 2018, 23:48:57 »
I believe bigger props are more efficient and would give longer flight times. Also I would guess that, to a degree, a wider frame gives more stability, down side being difficult to transport.
You might be able to find some thrust tests on the motors you have/are considering. That might help or do the manufacturers list voltage/prop size/thrust/current figures?

Offline Dave@F.P.heaVen

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #6 on: November 30, 2018, 10:22:10 »
Copied from HK website:

Spec:
KV(RPM/V): 390
Lipo cells: 6s
Max Surge Watts(W): 300
Working current: 11 amps
Max.current(10s): 15 amps
No Load Current: 0.25 amp
Intemal Resistance: 0.17 ohm
Number of Poles: 22
Dimensions(Dia.xL): 47.5 x 25 mm
Shaft: 3 mm
Prop: 12 x 3 - 14 x 5
Weight: 98 g

Although if you read the reviews, some people say they are fine on 18" :o

Offline ched999uk

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #7 on: November 30, 2018, 10:52:35 »
Copied from HK website:

Spec:
KV(RPM/V): 390
Lipo cells: 6s
Prop: 12 x 3 - 14 x 5
Weight: 98 g

Although if you read the reviews, some people say they are fine on 18" :o

That is for 6S so maybe people running 18" props are running 4S?

OP is suggesting he is intending to run 6S AND 16" props!!! So you might well be right that 6S needs smaller props.

Offline stickboy

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #8 on: December 02, 2018, 04:48:32 »
Here's the spec sheet from HK as well (somebody posted in the files section):



I did some testing today too, and yep, these motors are definitely not fit for 16" props on 6S based on how hot they got. I don't have a watt meter, but I did some thrust tests while taking temps. on a sloppy test rig I built and here's what I got (all running 6S with the new Lumineer 35A ESC I got in the mail yesterday):

1455 prop:
2 minutes @ 100% throttle: motor temp = 60 C
3 trials 5, 5, & 10 minutes @ 50% throttle: Avg. motor temp = 27.7 C, Avg. ESC temp = 20.7 C

1655 prop:
1 minute @ 100% throttle: motor temp = 82 C

I feel 16" could still be pulled off if you're easy on the throttle (basic hover maneuvers not flying like a racer), but I'm liking what I'm getting with the 14" props and will be sticking with those for my hexacopter build. Also, got an average thrust of 1398g at 50% so the spec sheet holds up and I am happy with that! ::)



Offline ched999uk

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #9 on: December 02, 2018, 12:44:23 »
It's good to test.
Looking at the spec sheet it says 'running current <11amps' and max surge current 15amps on 1447 props 100% throttle is 16amps!!!!!! So it seems like on 6S with 1447 props max continuous current means 75% throttle is highest without going into surge current and thus lots of heat!!!

1447 prop is less pitch (easier to spin, less thrust) than your 1455. So do watch the amps. Can you build in a current meter so you can see values on tx or osd?

Looks like you are assessing things and aware of limitations and heat.

Keep the updates coming.

Offline stickboy

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Re: Quality ESC for low KV 16" props running on 6S?
« Reply #10 on: December 03, 2018, 08:19:30 »
1447 prop is less pitch (easier to spin, less thrust) than your 1455. So do watch the amps. Can you build in a current meter so you can see values on tx or osd?

Do you think the little bit of extra pitch is enough to be worried about? I probably would go with the 1447 just to be safe, but I've developed a strong liking of "T-Style" props after a nut coming loose once, and there isn't a thing out there for a CW prop adapter that fits nor anything "T-Style" under the 5.5 pitch.

As far as current meter, I did just order one of those watt meter/power analyzer units. Thinking I'll throw it on for some early flight tests if it's safe. Going to be using my DJI iOSD mini so unfortunately not sure it has any current ready abilities.