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HelicopterMain Discussion › Understanding Lipo and ESC....
08-29-2017 01:52 AM  24 days agoPost 1
InvertedDude

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USA

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Okay, can anyone explain why I use less MAH while running at full speed compared to 75% on power.

Lipo 6s

Glacier 5000mah 45c

Example 1

Castle ESC 100A
600XL 1650 KV 6 pole

Throttle curves in S1 75% all across

6 min flight 4300mah charged back into battery

Example 2

Castle ESC 100A
600XL 1650 KV 6 pole

Throttle curves in S2 95% all across

6 min flight 2760 mah recharged?

Why is it running the helicopter at whipping speeds uses less power?

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08-29-2017 02:16 AM  24 days agoPost 2
EEngineer

rrProfessor

TX

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That does seem weird....

Other than the curve difference....what's the difference between S1 and S2.

What happens if you set S1 to 95%, too?

And then repeat.....any difference?

Logo 600SXs, 700XX, 800XX

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08-29-2017 02:51 AM  24 days agoPost 3
Doublah

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USA

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That does seem weird....

Other than the curve difference....what's the difference between S1 and S2.

What happens if you set S1 to 95%, too?

And then repeat.....any difference?Logo 600SXs, 700XX, 800XX
I think he is talking about the headspeed at roughly 75% throttle in S1 and 95% throttle in S2. A little more description on style of flying might help. If you are tossing it around heavily, I can easily see loading the motor and ESC in S1 and therefore pulling a lot more amps. It can become really inefficient at lower speeds doing 3D. Hovering not so much.

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08-29-2017 02:52 AM  24 days agoPost 4
InvertedDude

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USA

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EEngineer

I will get on it!

Its weird, my thinking the more speed equals more amps.

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08-29-2017 02:58 AM  24 days agoPost 5
Doublah

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USA

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Not necessarily. It can have just the opposite effect depending on many factors, but especially 3D where you are constantly loading the motor and ESC. ESC's are generally most efficient at or near 85-90% on the throttle curve. That is why the KV of the motor and gear ratio are so important for efficiency, power and how well the ESC can work. A lot of people blame ESC's for getting to hot, catching fire and a lot of times it is the wrong motor, gear ratio or battery voltage that will cause major problems. Not always obviously, but a lot.

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08-29-2017 03:05 AM  24 days agoPost 6
Doublah

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USA

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Do the same test as you mentioned in your post and than measure the motor temp after each run. Make sure you fly the same way for each flight and I bet you will see the motor alot warmer at the 75% throttle.

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08-29-2017 03:18 AM  24 days agoPost 7
Doublah

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USA

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Use the Castle Creations log on the ESC for temps and amps. Great tool to show the difference.

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08-29-2017 03:29 AM  24 days agoPost 8
InvertedDude

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USA

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Doublah

Great Idea....will get on it!

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08-29-2017 05:28 AM  24 days agoPost 9
spaceman spiff

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Tucson

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Timing might make a difference. (?)

There is also a PWM rate. If the rate is too low maybe... ?

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08-29-2017 07:06 AM  24 days agoPost 10
grimthenoble

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Sunnyvale, California

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Try hovering the helicopter at 75% power and at 95% and tell us mah used for 4 mins, (it may be boring). If you had similar flights it is because you are asking the motor to do same amout of work at slower speeds than you are at higher speeds. your motor couldn't do the same amount of work at slower speeds so your amp draw was much higher. which I'm sure your temps where a lot higher as well. are your main blade pitches the same at flight mode 1 and 2? Usually you run a few degrees less pitch at 75% than at 95%.

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08-29-2017 11:10 AM  24 days agoPost 11
wjvail

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Meridian, Mississippi

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Hey I-Fly- Interesting question...

The difference in battery consumed is huge. There is almost a 1,600mA difference. Same battery for each example? Same day/flight conditions? Can you repeat the results? I'm not surprised there is a difference. It's the magnitude of the difference that I'm struggling with.

Can you do a simple hover and look at the Castle Creations current draw? The charting function should report and average current draw. I fly a 450 with a CC 50 ESC and use the telemetry function to look at current draw in flight. There is some variation between the different head speeds as you would expect but in a steady hover it is less than .5 amp for a helicopter that draws around 6 amps while hovering. It is nowhere near the 60% jump you are seeing.

I would have a look at your testing methodology.

"Well, Nothing bad can happen now."

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08-29-2017 01:23 PM  24 days agoPost 12
pH7

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Sterling Heights, MI - USA

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Usually you run a few degrees less pitch at 75% than at 95%.
I think it would be just the opposite. In a hover, if you lower the head speed it will take more pitch to maintain the hover. Higher pitch will require more torque. Supplying more torque will draw more current. There are too many unknowns to determine if this is the actual case or not, but it is one possible scenario.

Phil Heavin

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08-29-2017 01:50 PM  24 days agoPost 13
Pistol Pete

rrProfessor

Seffner, FL

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ESC and Brushless motors are most efficient at 100% while anything less gets dissipitated into heat.

Lower head speed require more pitch, thus more drag and higher amp draw. Same applies to tail blades pitch and servo works more as well. Specially if tail was not set up mechanically for given a given head speed

As mentioned, hovering for a X amount of time is your best testing platform.

Test should be done with same battery at same temp. Internal resistance readings should be equal for both high n low speed test. Best option is to let battery rest between test and charging.

Once you are done testing, test with lower ESC timing. You will also see a difference in your results.

Yes, may be long and boring but great information, understanding and knowledge is gained.

You could take our word for it or experience it hands on.

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

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08-29-2017 04:49 PM  23 days agoPost 14
grimthenoble

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Sunnyvale, California

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I should of mentioned less pitch at full cyclic, which in turn makes helicopter a bit less snappy because of the less power and pitch available. your hover would happen just a touch above where heli would hover at 95% throttle. I don't think the difference in power draw comes when he is in a hover.. its when he is demanding power. And the difference comes when he still is trying to fly like he is in 95% at 75% power.

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08-29-2017 05:49 PM  23 days agoPost 15
EEngineer

rrProfessor

TX

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Seems like we'll have to wait for his results....

S1 at 75% and then at 95%....flat curves.

Then, S2 at 75% and then at 95%....flat curves.

Changing 1 parameter at a time....

Logo 600SXs, 700XX, 800XX

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08-29-2017 06:40 PM  23 days agoPost 16
InvertedDude

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USA

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Test 1 75% S1 Throttle curves

Hover within 30 feet circle no climb outs

Motor Align 600XL 1650 KV
Castle 100Amp (set not to exceed 125 amps)

12 khz
0 Pulse timing
Poles 6

Few seconds past 6 minutes

ESC 159F

Motor 140F

Lipo 80 F

MAH recharge Status waiting:

Landing Voltage 23.13V

Total 2010 MAH recharged

Flight time expected around 12 minutes

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08-29-2017 07:21 PM  23 days agoPost 17
InvertedDude

rrApprentice

USA

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Test 2 95% throttle curves

Hover within 30 feet circle no climb outs
Motor Align 600XL 1650 KV
Castle 100Amp (set not to exceed 125 amps)
12 khz
0 Pulse timing
Poles 6
Few seconds past 6 minutes

ESC 136 F
Motor 137 F
Lipo 98 F

Pinon gear 10T
Main gear 170T

Landing voltage 22.64v

Recharge awaiting status:
3095 mah

I had to wait a long time until pack cooled off.

This is the results.

Flight times expected around 7:30 mins

Conclusion:
I don't know what I am talking about! LOL!

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08-29-2017 10:06 PM  23 days agoPost 18
Doublah

rrVeteran

USA

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Hovering a 3D helicopter at 75% throttle is always going to draw way less amps than at 95% throttle. We are not lifting much weight. The comparison needs to be done under normal 3D flying conditions. That is what the helicopter is deigned and setup for...not hovering.

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08-29-2017 10:24 PM  23 days agoPost 19
spaceman spiff

rrKey Veteran

Tucson

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Glad the mystery is solved.

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08-29-2017 10:25 PM  23 days agoPost 20
EEngineer

rrProfessor

TX

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S1 seems about right....

What about S2 with the same conditions?

Logo 600SXs, 700XX, 800XX

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HelicopterMain Discussion › Understanding Lipo and ESC....
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