I have a flying issue , Please help me out

[Saurav1711]

I have built an FPV drone using emax motors and escs . The problem here is that the drone doesn’t fly more than half a feet from the ground level. I give maximum throttle and it just hovers half a feet above the ground. Can you please help me with this issue . Thank you

 

[holtneil]

Hi did you calibrate the esc so it knows zero and max throttle
also can you give the guys more info what FCB , size of quad etc the more info we have the better the help

 

[Saurav1711]

I’m using Emax 45A Blheli Dshot 1200 esc . In Betaflight I calibrated with the option MULTISHOT. I got all the beeps which generally ESC get. When i opted for DSHOT in beta flight, while i was calibrating, I didn’t get that beeps. Its a 240mm frame with Matek F722 STD with Emax 2300KV motors. I have tried everything but not catching up the error. Please help me out with this

 

[RENOV8R]

In the receiver tab of Betaflight, when you apply throttle, does it show the throttle channel as going to the max and min? 1000-2000

 

[Saurav1711]

Yes when i turn on my receiver and increase the throttle , it goes from 1000-2000.
Is it the battery which is affecting it ? Its a 11.1V

 

[wafflejock]

The voltage is fine for that kv you should have plenty of power to get into the air, I've flown both 3S and 4S on 5" quads either way should be sufficient given your motor kv, shouldn't be an issue but what props are you using too have a link? Does it just seem to fly under powered or doesn't get more than 1-2ft off the ground?

 

[Saurav1711]

I can probably share a clip of the quad flying. I feel it flies under powered. I mean I cant really figure it out . It just fly like half a feet off above the ground, that's it. I mean the throttle is maximum and still it does not. The props I am using are

EMAX AVAN-R PROPELLER - 1 SET BULK-2 CW+2 CCW 5-inch 3-blade FPV racing Propeller

 

[mchaos]

what kind of voltage drop on the battery? maybe the battery is shot.

 

[Saurav1711]

How do i know the voltage drop on a battery? I accept that the 3s lipo battery I’m using is 400g and not so good.

 

[wafflejock]

Did you fully charge to 4.2V per cell after trying to take off/fly for like 1 minute has it dropped to 3.7V per cell? If so the battery is bad. Some balance chargers you can hit the status button while charging to see individual cell voltage or to see the internal resistance. There are also little standalone lipo tester modules you can plug into balance lead that will measure voltage (roughly) or better ones that are accurate and can measure IR of the cells as well. The numbers are all sort of relative but I see something like 8mohm to 15mohm per cell, would just try a fresh battery to take that out though and make sure it's well charged. Have been using ovionic brand ones for a while and haven't seen any kind of issues like that, even with a damaged or dying battery I can typically fly high up it just can't fly for very long.

 

[wafflejock]

Extra strange thing is all the components sound like they should be good, some sort of vid clip uploaded to YouTube or otherwise and linked here would help.

 

[Saurav1711]

Hmm if its possible i can catch you up on any social media platform ? If you don’t mind . I can share you the video?

 

[mchaos]

Like Waffle said, a fully charged cell should be at 4.2 volts. you have 3 of those, so full charge on the pack should be about 12.6. So in order to know the voltage drop you need to be able to see the voltage you are using. There are a few ways to do this. One is if you have an OSD which displays the voltage in the video feed. The other if you don't have an OSD is with telemetry to the radio. For instance if you have a FRSky Taranis, you can set up a screen on the controller with voltage. Also, min voltage and max voltage.

If you have OSD, make sure your voltage is displayed in the feed. You should see close to 12.6 volts on a full charged pack. When you arm and take off, and throttle up, take note of how low the voltage drops as you raise the throttle. This is your voltage drop. All packs will have some sort of voltage drop. But it's minimal on a good pack. So if you throttle and its still at like 12 volts, or 11 point something then it's not your batt. If you throttle up and it drops to like 10 volts or lower, you have a bad pack. That would be why your quad won't lift off.

Some other reasons..
Props - Upside down props don't provide as much thrust. The also sound weird and high pitched. could be too small props, or not enough pitch but unlikely. Un balanced props. If you have an unbalanced prop or props, because of all the vibration your quad is trying hard to keep you level, so all your motors are speeding up and slowing down like crazy and cant speed up because it's trying to maintain control. You would know this by erratic sounds.

If it's not the battery, and it's not the props, and everything seems to be working otherwise, then you have some sort of config problem. Either with the firmware or the wiring...

Something to look at if you have BLheli32. There is a setting to limit amp draw. If that for some reason is set really low, then it's not letting the ESC's draw enough amperage to lift off. It would have to be set really low, because even when you set this, and you hit the limit, the quad will slowley spin up as the amp draw drops after the initial surge.

You should post vids on youtube and post link. Upload images to imgur and post links here for us to see.

All in all you could re flash and start from scratch on config and insure wiring is correct.

 

[wafflejock]

Yah sorry on the social media platforms or chat but don't really use those outside of slack for work or hangouts and text messaging, if you upload vid somewhere though will be the most helpful for diagnosing what's going on and or a couple close up images of it (realize this site isn't the best about sharing high res anything but can upload to Google drive or any other cloud and share a link here too)