Very low flight time please help

M

Marc f

Member
Hello there I need some help with my home built quad copter.

The quad is run by an Apm 2.6

4 * 1400kv motors and 10*4.5 plastic props

30A ESC

Weight without battery is 950grams

When running with a 3s 3000mah 30c battery with a total quad weight of 1200grams I get about 7mins of flight time on a good day.

I want to upgrade to Carry a camera and mount so I did a test with a 500gram weight to see how it went flight time it got 4-5mins

I wired two 3000mah batteries together in Parrell to see how long a flight time I could get to see if increasing the battery mah would help. With a total weight of 1970grams with the 500gram weight I only got 7:30mins of flight time the motors were warm after this but not to hot



Can someone please help me with why I'm getting so short of a flight time even when I'm just flying around with no extra weight.

Do I have the wrong props the wrong motors ?

Thanks very much for all help provided I'm new to this but want to get better thanks again
 
Your using too big of props on too high KV motor. I have a 3ib AUW quadcopter that is running on: 9'' props, 3S battery, and 1240kv motors. My motors really should have 8'' props, so yours are being overworked. I suggest you grab some 8'x4.7 slowfly props.
 
Just read, that you are going to be carrying a camera, I suggest the Runcam, it is nice-n-cheap and takes really good videos. Also if you don't watch you are going to burn your motors up, if you later wanted to upgrade to a heavier lift quad 800-900 kv motors would be my suggestion, and you could lift a lot more.
 
Ok great thanks for your help I did find some motors to try on hobby king I was looking at

Donkey ST3508 730kv

Just to try something a bit cheaper to get the job done and then if that works get some good Motors

Do you think 730kv is ok for everything else I have ? Or should I try and stay around the 900kv mark?? Speed is not a big thing as I want to use it for camera work.

Finally what would be a good size battery to upgrade to in mah before it is no longer worth it???

Thanks again for your help it's much appreciated
 
Hi Marc try playing with 4 cell as well the ESC should be ok then low KV motor , if you want to stay with 3 cell go for the multistar 5200 mah is light for its size made just for quads , a 1000 kv on a 10x4.5 3 cell 2200mah should give you 15mins say 10 mins with a camera , it is the prop size to the motor speed killing you
Low kv big props big mah will give you flight times
The donkey st3508 is not the nicest looking motor but will do the Job , see what the max prop that will fit on the frame like i said the ESC will take the power pull of the motor with big props, this motor will work on 4 cell
 
Thanks holtneil, I want to try and stay a 3 cell because I already have a fair few 3 cell batteries.

I'll buy some new motors today and keep you guys updated on how it goes thanks very much for all your help
 
holtneil said:
Hi Marc try playing with 4 cell as well the ESC should be ok then low KV motor , if you want to stay with 3 cell go for the multistar 5200 mah is light for its size made just for quads , a 1000 kv on a 10x4.5 3 cell 2200mah should give you 15mins say 10 mins with a camera , it is the prop size to the motor speed killing you
Low kv big props big mah will give you flight times
The donkey st3508 is not the nicest looking motor but will do the Job , see what the max prop that will fit on the frame like i said the ESC will take the power pull of the motor with big props, this motor will work on 4 cell
Click to expand...

Holtneil just one more quick question.

I looked at the multistar battery you said but most of them are rated at 10c with busts of 20c for 10 seconds. The motors I got are 16amp (that is at 1.2kg per motor so I won't be anywhere near that weight) but that C rating isn't high enough is it?
 
I like them, the 4.7 pitch really helps. The slowfly style props seem to work nicely, plenty of power, and my quad is an aluminium tank haha.
 
Hi Mate George answered right , the multistar battery was made from the start to just run multirotors , as they dont need the high C rate you would need with a 450 or 500 class helicopter , so the C rate can be lower and in return they up the mah for longer power runs ,they are lighter too which is nice to keep the weight down
If you go for the lower KV motor with a bigger prop you can up the pitch As George said ,On my 450, 525 and 666 mm I used 10x4.7 prop ( carbon fibre) your get a lot of lift, on my 700mm quad I run a 650kv heavy lift pan motor and these run a 14x5.5 carbon prop the motors dont even get warm , so see how big of a prop your frame will run , the motor will run 13x4.0 , you can try a 13x5.5 this will give you a 1.5 extra pitch that will be a mega amount of lift
http://www.hobbyking.com/hobbyking/..._CCW_Rotation_with_Dual_Mountings_1pair_.html
 
I run 1000kv motors on a 450 frame with 30c 2200mah battery and get 10 minutes with 10.45 props when i add a gopro and mount it goes down to about 8 minutes. Thats with medium flight speeds nothing too nippy. Your could go down to 8045 or even 8060 with those motors but again as already said the prop is just too big for that motor power is probably being lost to heat in the esc or motor windings.
 
Hi I ran 10x4.7 on 1000kv had lots of lift just go up on mah it will help with flight times , My son runs a 450 on 2200mah 10x4.5 no camera but flight times are 15mins
 
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