50A consumption during hovering!

Hello!
I just made a large 7kg weight hexacopter with 6x Gartt ML5008 400kV engines, 6x Hobbywing XRotor Pro 40A ESC with DEO ON, 6x 15" carbon fiber propellers. I have on board Tattu 16000mAh battery and it lasts for 8 minutes of hovering flight! I have a latest Ardupilot firmware on my pixhawk 4.

Does anyone have an idea what could be the reason for this and how to improve it?

Thanks!

50A consumption should be 15min of flight time with 20% reserve on 16Ah.

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You are using a a very small props for those motors. I have a simmilar motor from Tmotor 5008, and I user a 18" prop. Anyway, I have found this chart from your motor, and it say it can handle a 17" porps. This will give you more flight time.

In your current configuration, the chart it say if every motor must move 1.2kg (7 kg aprox total from your hexa), you will draw 5.8Amp for each motor, for a 35 amp aprox. So may be your current and voltage system are not calibrated, or your battery is a quite old. what is your landing voltage? what kind of voltage and current system are you using?
and share your log file

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ZDRONA,

I ran your configuration through eCalc, which indicates the drone should be burning about 8 amps per engine at hover, so 48 amps for 6 engines. I assumed a 6s battery. All the other parameters look good. Calculated thurst/weight is 2.5 so your propeller choice is adequate. If you run 17 inch props, eCalc predicts two more minutes of flight time, but at max power you’d exceed the amp rating of your ESCs and push up the engine temp.

The only thing I can think of is your battery wasn’t fully charged or it’s old as suggested by AMV.

Let us know what you discover.

Dave

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Thanks for reply guys!

My landing votage is set:
BAT_LOW_VOLT: 22,8v
BAT_CRT_VOLT: 21,6v
(I’m trying to land between these values)
BATT_CAPACITY: 16000mAh
BATT_MONITOR: 4 Analog Voltage and Current

My Tattu battery is brand new.

I wanted to change my propellers to SUNNYSKY EOLO 15" or T-MOTOR MS1503 maybe it will helps a little bit.

Thanks!

Wetransfer link for my telemetry logs: https://we.tl/t-vvN6wKxOoy

You likely won’t get ~85% of pack capacity if you are flying to 3.6-3.8V/cell and 50-52A at hover is right. You got what you built. Depending on your prop pitch I see a hover throttle a bit higher than desired. I used 1555. 1755, if they would fit your frame, would produce a good target hover throttle. Or lighter weight of course.

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I can’t make it lighter because I have camera gimbal with Sony camera on board.

So, the best option is change motors on something smaller for 15" propellers.
Do you have any suggestions for the right motors?

Frame is ZD850 and bigger propellers (17") won’t fit.

A motor with a bit higher kV but not much higher. it might not be worth doing, perhaps just live with a 58% hover throttle. You could look for some higher pitch props.

Post a link to the .bin flight log (not Tlog), lets see what’s really going on.

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Here you are: https://we.tl/t-yLY1LIMKIJ

This craft is flying pretty well. The hover thrust commanded outputs are not bad and tuning is pretty good. The Rate Filters look a bit low for a15" craft but as mentioned tuning is good so perhaps keep it.

I think at this weight you will just have to live with the flight time you are seeing. Determine what a good low battery voltage to FS from by mah consumed (80-85% of pack capacity) and fly to that.

Set these parameters:
MOT_BAT_VOLT_MAX
MOT_BAT_VOLT_MIN

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Good to know!
Thank you for your time.

A tattu can handle better low voltage.

Im using this setup for the same battery (no 50Amps usage)
BAT_LOW_VOLT: 21,5v
BAT_CRT_VOLT: 20,5v

That will give you more flight time.

But if you ask me, you should use a 20Amp tattu and 17" prop.

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Not going to fit on this hex so not much point…

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I have decided what I do. I will buy longer carbon pipes for arms and will buy a new propellers 17".

Now the diameter of the drone is 85cm, this will change to 91cm. That frame is pretty solid, so I think it can handle it.

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Now I have Tattu 16000mAh 15C.
You mean by that Tattu 16000mAh 30C or Tattu 16000mAh 15C HV?

This is almost my set, and you can see it takes in hovering 21A!

I have the same frame, 6 4010 arris motor, 16"prop, 1 Diamon 30000mah, 7KG, 30 minute flight… I think you need to change your motors for ones more sutible to that frame

If you make your arms longer, you have to change your landing too.

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What is your current (A) consumption?

Just some background info here to show that what you are seeing is realistic.

eCalc of your setup (~52A at hover predicted):

Actual from log:

Good correlation which is what I typically see with eCalc. Perhaps it’s spot on and your current calibration is off :slight_smile:

My guess at that? 49A

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38-42Amp average, was very windy last time

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