Hey guys.  
  
I've just flew my drone today. I was in the air for roughly 2 minutes just hovering around moving roughly 20ft slowly away from myself. I decided to give the drone a little power and punch it up to maybe 50ft and in a large circle roughly 30ft in diameter. Everything was going well until i flew it back to it's landing area at some speed, slowed down and brought the throttle down from 60% to 50%ish to remain in a very slow decent.  
The drone seemed to start increasing it's decent speed so i throttled up a little. Just a few notches on my radio and the drone just kept falling, it stayed level using GPS mode just kept coming down faster. I ended up hitting full throttle and within a second or two it had hit the ground, snapped the landing legs (Damn plastic rubbish) so i hit the motor cut switch which saved my props at least.  
  
I'm now 3 legs down, an arm down and confused about why this had happened. I've just put the battery on my balance charger and it did come up as R: 3S SER - S: 4S SER or something like that and battery voltage at 12.68v (before i started it was 15.58v)  
  
Did i just drain the battery too much? It's hard to believe as using the "Drone Flight Time Calc" online it shows i should be able to maintain a flight time of roughly 10 minutes which i assume would be either hoovering or full throttle not mixed flying. My timer registered a total flight time of 3 minutes 47 seconds before it came down.  
  
The drone came down next to a metal fence (Construction Type that sit in the large black block feet things) could that've blocked my radio signal at the end?  
  
If it helps my Drone specs are,  
Racestar BR2212 motors  
10x45 props  
Turnegy opto 20A ESCs  
6200mah 120C 4S Lipo (Brand - Uruav)  
Naza M V2 FC  
  
Total weight 2119g I've just weight the entire thing to be sure. This actually increase flight time to 12 minutes according to that drone flight calc website. So 4 minutes should be fine.  
What sucks is i started to feel more confident at flying LOS in my little protective bubble area.

As an idea this fence was in the area where the drone landed beside. There's a couple of these right by my house. Would these block the radio? If so i guess lesson learnt. Otherwise i'm thinking my battery has an issue with the whole 3SER thing as it typically shows as 4S for both.

(14-Apr-2020, 04:44 PM)bLoWsMokE Wrote: Yes you killed your battery. 4S charges up to 16.8 not 15.8 you were already flying a not full battery. What happened was exactly because you killed your battery. You most likely damaged it as well.

Your set up is very strange as well.... ur flying an X class drone on  4S battery?

4 minutes for that is actually a long time when you were only charged to 15.58V. The only reason you get more than 10 seconds is because it's a 6200mah battery.

X class drones usually use 12s batteries I think, so your voltage is 3x too small and even worse when you don't fully charge the battery and ur making up for that with an inordinate amount of milliamp hours.

The issue is 100% your battery. And on top of that I'm surprised your ESC's don't just burn out immediately upon taking off at only 20amps.... X class ESC's should be at around 80 amps. And the reason for not blowing the ESC's is the motors you're using.

Those motors are NOT suited for X class drone AT ALL. The motors say they are "great" for 8 -10 inch props but....... man..... Your set up is very unorthodox to put it lightly. You should drop the prop size by at least 3 inches and lower the weight by 1600 grams, and lower the battery size by around 4000 MAH. Even then I'm not sure even that would be a good idea. your build is just strange.

I assure you though, the reason it fell is because you drained the battery too much. The reasons you drained the battery too much are many fold.

So would an easy fix be to swap out the hex frame for a smaller quad frame and remove 2 motors/ESCs?

The motors show with 10x45 props according to the spec sheet that it pulls just under 20A at full throttle with those props. From all the research i thought a 120C battery had enough to power all 6 esc's at 20A each.

Quick Google search came up with 12S batteries weighing the same as my entire current build. If i was to use one of those my drone would weigh almost 4kg that's not taking in to consideration much larger esc's and motors i guess would be required to produce enough lift for the entire thing.

(14-Apr-2020, 05:20 PM)MrTrendizzle Wrote: So would an easy fix be to swap out the hex frame for a smaller quad frame and remove 2 motors/ESCs?  

The motors show with 10x45 props according to the spec sheet that it pulls just under 20A at full throttle with those props. From all the research i thought a 120C battery had enough to power all 6 esc's at 20A each.

Quick Google search came up with 12S batteries weighing the same as my entire current build. If i was to use one of those my drone would weigh almost 4kg that's not taking in to consideration much larger esc's and motors i guess would be required to produce enough lift for the entire thing.

I re-wrote my comment like 8 times haha.... I never seen a build like yours but after looking it up I changed my comment to more suit what you're going for.... my thinking was that you wanted to fly freestyle line of sight, which the drone you built would not be good for..... 

yes you're right.... you want 4s.... 12S batteries are for a freestyle X class FPV drone which is not what you're building and what I THOUGHT you were doing because I had never seen anything like what you are doing... it was pure ignorance on my part..... and BTW the ESC's don't make... the motors draw power through the ESC's from the battery. if the motors draw more power than the ESC's can handle (in your case 20 amps) then the ESC's would blow..... that's why I said the motors are why they aren't blowing.

My original comment was mostly wrong, sorry. It's just that your particular build is very unorthodox and doesn't really fit when it comes to FPV and racing drones.... so I was ignorant of what it was you were doing.

Yes the main point is that all you have to do is charge your batteries to full capacity. That was your only issue.... ignore everything else I said and just charge your batteries to 16.8V which is 4.20V per cell and never discharge past 3.5.

Once you start to feel that you need to give more throttle than usual to keep it in the air.... shut the drone down IMMEDIATELY you've already drained your battery too far.

Edit: I deleted my original comments ;D They were ignorant and 25% wrong.

(14-Apr-2020, 05:26 PM)bLoWsMokE Wrote: I re-wrote my comment like 8 times haha.... I never seen a build like yours but after looking it up I changed my comment to more suit what you're going for.... my thinking was that you wanted to fly freestyle line of sight, which the drone you built would not be good for..... 

if you're just going for a DJI style of flight then you will be fine with what you have.... just charge your battery to full capacity and you should get the flight times you are looking for... proly not 12 minutes but 10 minutes would proly be possible.

the kind of build your doing is more like a production model drone not a hobby grade one.... The X class's I'm talking about are hobby grade..... yes those motors are suited for 8-10 inch but you're not going to be flying FPV racing like you see on youtube..... it's gonna be more just casual flight.

What you're doing would be good for getting a camera and doing photography, and maybe even using a camera with head tracking... that would be cool!

Ahh ok i understand now.  
  
Yeah this being my first ever drone build i wanted something slow, smooth and stable. Something to practice with while having safety features. Hence why i wen't the Naza route. 
I have a video transmitter and receiver. One of those ones you plug in to your phone (I've got a Samsung VR headset which will allow me to go FPV) but that's more of a "Ow shit i can't see which way im facing" type of deal where i can check on the screen to show me if i have a bunch of tree's i'm heading towards etc...  
  
I'm thinking of buying a slightly smaller quad frame and swapping over the parts. Only reason i decided on the hex was for motor fail redundancies. If i decide to go tiny i'll more than likely want end up researching drones all over again and maybe investing in a 3D printer as i'm starting to see the cost mount up when i break stuff.

EDIT: No worries. I'm pretty lost in this world once again. I thought i had everything figured out and i'm having to learn all over again certain parts. I'll be sure to charge my batteries fully next time. I assumed they were charged fully as i had taken them from the charging cradle i have. I guess a costly mistake to remind me of further safety checks to complete before flying. (The CAA is going to love the safety sheet i have)

(14-Apr-2020, 05:34 PM)MrTrendizzle Wrote: Ahh ok i understand now.  
  
Yeah this being my first ever drone build i wanted something slow, smooth and stable. Something to practice with while having safety features. Hence why i wen't the Naza route. 
I have a video transmitter and receiver. One of those ones you plug in to your phone (I've got a Samsung VR headset which will allow me to go FPV) but that's more of a "Ow shit i can't see which way im facing" type of deal where i can check on the screen to show me if i have a bunch of tree's i'm heading towards etc...  
  
I'm thinking of buying a slightly smaller quad frame and swapping over the parts. Only reason i decided on the hex was for motor fail redundancies. If i decide to go tiny i'll more than likely want end up researching drones all over again and maybe investing in a 3D printer as i'm starting to see the cost mount up when i break stuff.

An FPV drone would more sturdy and resistant to breaking than what you have.... however, you'll be going MUCH faster so it will proly even out haha.

but yeah man go 5 inch or 3 inch propellers.... 3 inch is safer and works just about as good as a 5 inch. So you want around 130mm-150mm frame for 3 inch and 220 -250 for 5 inch. These are not strict numbers BTW... just general.

For instance, I'm using a 237mm frame 5 inch props 2306, 2450 KV motors 60A ESC (which many people would say 60A ESC's is over kill, but an ESC that can handle more amps has a less chance of burning because of too many amps so that's just my personal preference thing to do, I could explain more in detail but w.e) with a 1550 MAH battery at 100C. 

My 3 inch is 145mm 33A esc 1407 motors 3600kv 850mah at 45C (I used to have R-Line 850mah 95C but they both failed on me for w.e reason so I'm stuck with the first batteries I ever bought).

MrTrendizzle

EDIT: No worries. I'm pretty lost in this world once again. I thought i had everything figured out and i'm having to learn all over again certain parts. I'll be sure to charge my batteries fully next time. I assumed they were charged fully as i had taken them from the charging cradle i have. I guess a costly mistake to remind me of further safety checks to complete before flying. (The CAA is going to love the safety sheet i have)

You definitely wanna buy a digital charger. over charging your batteries or over discharging them will... WILL damage them.

When I first started this hobby i thought 14.8 was full charged because it says on the battery 14.8V haha... so I was like... why are my batteries only last 30 seconds... and charging in 5 minutes... it took me flying like that 2 or 3 times before I actually figured it out ;D So don't feel bad.

But yeah you definitely wanna get a charger so you can balance charge the cells and know what the voltage is, and be able to charge them to storage voltage.

So when you're not using the batteries never leave them full charged.... and when you're not using them for a while they should all be at around 15.2V 3.80v per cell is storage. That's what the charge is at when you buy them (hopefully). When you store lipos you always want ach cell to be at 3.80 or as close to it as possible.

It could likely be your battery not being fully charged. The resting/recovered voltage of 12.68V (3.17 per cell) could mean that you dropped below 3V during your flight. Below 3V, most multirotor do not have the power to spin the props. And you can damage the lipo pack.

Flight time and voltage are not great indicator for when to land. The best is actually current (amp) used. At full charge, you can safely use 80% of the capacity of the lipo. Unfortunately, I don't think Naza has this feature.

Anyway, if you want to use voltage, tried to land when you are at 3.4-3.5V per cell for several seconds. Dropping below 3.2V is usually a very fast drop below 3V.

(14-Apr-2020, 05:51 PM)voodoo614 Wrote: It could likely be your battery not being fully charged. The resting/recovered voltage of 12.68V (3.17 per cell) could mean that you dropped below 3V during your flight. Below 3V, most multirotor do not have the power to spin the props. And you can damage the lipo pack.

Flight time and voltage are not great indicator for when to land. The best is actually current (amp) used. At full charge, you can safely use 80% of the capacity of the lipo. Unfortunately, I don't think Naza has this feature.

Anyway, if you want to use voltage, tried to land when you are at 3.4-3.5V per cell for several seconds. Dropping below 3.2V is usually a very fast drop below 3V.

Dropping down to 3.4V I start to see a rapid decline in voltage immediately to a point where full throttle just makes my drone slowly sink. You go that low when you fly Voodoo? I used to but then I ruined all my batteries, so now I never go under 3.6 if I can help it.

(14-Apr-2020, 05:51 PM)voodoo614 Wrote: It could likely be your battery not being fully charged. The resting/recovered voltage of 12.68V (3.17 per cell) could mean that you dropped below 3V during your flight. Below 3V, most multirotor do not have the power to spin the props. And you can damage the lipo pack.

Flight time and voltage are not great indicator for when to land. The best is actually current (amp) used. At full charge, you can safely use 80% of the capacity of the lipo. Unfortunately, I don't think Naza has this feature.

Anyway, if you want to use voltage, tried to land when you are at 3.4-3.5V per cell for several seconds. Dropping below 3.2V is usually a very fast drop below 3V.

I'm looking at getting a camera with onboard OSD which i assume will display my drone battery voltage so i'd be able to use that as my "Time to land gently" indicator rather than "Ow shit incoming WTF happened?"

Quote:BlOwSmOKe  

You definitely wanna buy a digital charger. over charging your batteries or over discharging them will... WILL damage them.

When I first started this hobby i thought 14.8 was full charged because it says on the battery 14.8V haha... so I was like... why are my batteries only last 30 seconds... and charging in 5 minutes... it took me flying like that 2 or 3 times before I actually figured it out ;D So don't feel bad.

I've currently got a Lipro balance charger. I charged them yesterday and only plugged the battery in to check something within the DJI assistant. I guess i didn't charge correctly. Maybe i used the balance option rather than charge. I assume the balance option just brings the voltage per cell equal rather than fully charge them all equally or something like that. My charger came with zero instructions.

(14-Apr-2020, 06:14 PM)MrTrendizzle Wrote: I've currently got a Lipro balance charger. I charged them yesterday and only plugged the battery in to check something within the DJI assistant. I guess i didn't charge correctly. Maybe i used the balance option rather than charge. I assume the balance option just brings the voltage per cell equal rather than fully charge them all equally or something like that. My charger came with zero instructions.

You want to use the balance option.

What is the DJI assistant? What kind of charger do you have?

So I found the battery I think https://usa.banggood.com/URUAV-14_8V-620...rehouse=CN


VOODOO.... Do you know what that 6.2 number on the battery label is/means?

(14-Apr-2020, 05:58 PM)bLoWsMokE Wrote: Dropping down to 3.4V I start to see a rapid decline in voltage immediately to a point where full throttle just makes my drone slowly sink. You go that low when you fly Voodoo? I used to but then I ruined all my batteries, so now I never go under 3.6 if I can help it.

I try not to but unfortunately it happens more often than I like. Yes, many times I don't quite make it back to my landing spot.

(14-Apr-2020, 06:34 PM)voodoo614 Wrote: I try not to but unfortunately it happens more often than I like. Yes, many times I don't quite make it back to my landing spot.

Same here... but not ebcause I don't make it back... but because I simply don't hve will power over my own actions

(14-Apr-2020, 06:14 PM)MrTrendizzle Wrote: I've currently got a Lipro balance charger. I charged them yesterday and only plugged the battery in to check something within the DJI assistant. I guess i didn't charge correctly. Maybe i used the balance option rather than charge. I assume the balance option just brings the voltage per cell equal rather than fully charge them all equally or something like that. My charger came with zero instructions.

You probably properly charged. Plugging in just to setup or look at stuff could have drained some of the lipo. Just check your battery right after a complete charge next time.

6.2 is just their way of indicating 6200mah. 6.2ah.