Hello guys, very curious about the topic, @kcee454 was your problem solved, from all your expertise what will be the best way to do motor alignment? did it liftoff?
After arranging a motor little, i get acceptable RCOUT values and i haven’t got errors…but there is still a very high voltage sag.It has very high sag initialy and perform better at 43-40v only… Does anyone have idea to reduce voltage sag…
Its my new log file
https://drive.google.com/file/d/195yt24s_2MQk0zWgqPpE6iSSo333b-pt/view?usp=sharing
The motor balance is better, but I think the drone is too heavy or the battery is worn out. In this hover test the motors are all sitting between 1725 us just to hover. That’s about 80%. This machine is working hard. Without a current meter it’s hard to say exactly, but it looks heavy to me. The battery voltage drop is pretty straight. By that I mean it drops right away but levels off for the current duration.
That level is just above 3.4v/cell. If this is a Lipo battery you’ve abused it pretty badly in this test. LiIon, then it’s not so bad.
If you’re trying to sort out a power issue, you really need a current meter.
I am using hexacopter of hobbywings x8 motor esc combo(https://www.hobbywing.com/goods.php?id=594)… its max thrust is 15kg/axis and i am using it for TOW of around 35 kg…i measured the current also with external hall effect sensor, its max is about 180A and in average 150-160A…Is it more for this drone?
160A from a 24Ah battery works out to 9 minutes flight time max but probably a lot less since your pulling so many amps… can you post a new log to see if the imbalance is fixed?
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As I calculated yesterday, your sitting about 80% throttle to hover. Give or take, but it’s a starting point. According to the link you sent at 80% throttle each arm is drawing 32.4 amps. Times 6 motors … 195 amps.
Don’t look at the max thrust. It’s not practical for regular flying. Even their recommended numbers seem odd. The 50% throttle thrust is 4 kg/axis and current is only 7.1 amps /axis. 24Kg MTOW. On paper, at 35kg you should be closer to 12.6 amps/axis or 76 amps. If the website is to be believed that should be between 18-19 minutes on your 24ah battery (but much less in real world minutes).
Possibilities:
- The motor manufactures numbers are “optimistic”
- Your drone weights more than you think. The power curve is exponential so it doesn’t need to be much.
- Your battery is worn out, or isn’t the capacity that you think it is. (more optimistic manufactures)
Are you running Lipo batteries or LiIon? Do your batteries have the C rating for these kinds of loads?
I doubt in batteries but sadly i have all batteries (12) of herewin, 12000mah 6s 20c lipo…they are new yet giving much sag…i had ordered tattu 22000mah battery which is misplaced and i couldn’t get that yet… which which battery do you recommend for heavy lifting drone?
GeoMuir, have you seen last log file i sent here (https://drive.google.com/file/d/195yt24s_2MQk0zWgqPpE6iSSo333b-pt/view?usp=sharing), I think it has acceptable balance, but sag is high…i verified the weight…its 36KG
You cant go wrong with tattu batteries, thats what I used in the heavy lift machines.
Geomuir, what is the tentative acceptable sag, which you get while flying heavylifting drone like this?
Continued and repeated use of a LiPo battery below 3.5v per cell will ruin the battery. There is no magic number for an acceptable voltage sag, as long as the running voltage remains above 3.5v/cell for the duration of your flight.
Installing 22ah batteries in stead of the 16ah you are using now will only increase the weight of the drone and making the problems worse. My recommendation is that before spending money on batteries you figure out what your current flow is (measured in flight, not on the ground and not calculated based on sales data) and why the motors are all running at such a high value just to hover.
I Couldn’t get power module for such high current (Mouch PM is unavailable here and i couldn’t find alternative for cube orange)…i am using wireless power meter (VAC8010), It giving around 180A max current while taking altitude and while hovering , its around 140-150A.
Based on the numbers you provided, for that weight you should be closer to 75A. You’re running twice as much current. You need to sort that difference out before moving forward.
Allister, can you please tell me, how can i sort that differences?..I tried without payload as well, there also i get instant sag of 2-3v in few sec, and after 47v, its discharging quite good.
I done some checking with some flight time calculators and they are agreeing with a 35kg machine on 12s 24ah is looking at 9minutes maximum. The batteries are only lasting 4 minutes because they are probably only rated for 2 or 3c discharge not 10c that the machine doing to them.
I have tested with herewin 12000mah (2s,2P) (12000mAh Batteries Herewin, Battery Type: Li-PO ( Lithium Polymer), Voltage: 25 V, | ID: 21928964412) setup and fullymax 16000mah (2S) setup (ROZETKA | Аккумулятор Fullymax 22.2V 16000mAh Li-Po 6S 25C UAV. Цена, купить Аккумулятор Fullymax 22.2V 16000mAh Li-Po 6S 25C UAV в Киеве, Харькове, Днепре, Одессе, Запорожье, Львове. Аккумулятор Fullymax 22.2V 16000mAh Li-Po 6S 25C UAV: обзор, описание, продажа)…i am getting much sag in both setup
The machine is too heavy. Even if your batteries could handle it your only going to get 9 minutes at most. At 180A your actually exceeding the current limit of the xt90 battery connectors even at 2p.
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But hobbywings x-series are famous in agriculture drone and X8 motors hexacopter are mostly used for 16L spraying drone, this setup are sold by many renowned agriculture drone seller as well…idk why i am having issue with my setup.
What altitude are you at? Are you up in the mountains?
not exactly…its 1400m above sea level…and if it worked good…i was planning to use at 2000-2600m altitude as well