How to increase flight time ?

Started by knvshrm, May 17, 2018, 12:24:19 PM

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knvshrm

Hello everyone I wanted to increase the flight time of my quad copter. The electronics I'm using are :
A2212 1400 kv motors
2200 mAh 3s 25c lipo
30amp esc
F450 frame
8045 props
On hover I am getting around 5 :30 mins of flight time. How can I increase the flight time ?
Awaiting suggestions
Regards

rcrcnitesh

Get a bigger battery, more efficient motors and props. Those two will help you a lot.
Maker | Aeromodeller | Teenager

taksh

Quote from: knvshrm on May 17, 2018, 12:24:19 PM
Hello everyone I wanted to increase the flight time of my quad copter. The electronics I'm using are :
A2212 1400 kv motors
2200 mAh 3s 25c lipo
30amp esc
F450 frame
8045 props
On hover I am getting around 5 :30 mins of flight time. How can I increase the flight time ?
Awaiting suggestions
Regards

Purchase 30c of the same version or purchase higher mah lipo battery with lower c as shown in this video.

knvshrm

#3
Which battery should I get ? I mean of what specifications ?

taksh

Quote from: knvshrm on May 17, 2018, 12:43:45 PM
Which battery should I get ? I mean of what specifications ?
buy battery according to amps for your A2212 1400 kv motors.
If one motor can draw 13 amps then 4 x 13 = 52 amps. If battery provided more than 52 amps then motors can be damaged as motors reached maximum rated current.
(5500 mAh * 10 c)/1000 = 55 amps is above 52
If battery is providing current according to your esc and motor then lipo is good for your quad.

I suggest you to contact some experienced person who has used high mah lipo for his /her quad.




rastsaurabh

Hello Taksh,
A few clarifications....
Battery does not push current in circuit, its the load which pulls current. In this case Motor.
Also C rating is the capacity which the battery can deliver ( at the time of need ) when demanded by the motor.

Analogy --> if a bucket full of water is battery then C rating can be thought as the size of hole in bucket with which water comes out. ( don't consider the height & pressure for this case)

So, if the Quad pulls say 20 Amps at full throttle and battery C rating is higher meaning it can give 20+ amps then no issue. But if C rating is lower then your quad will not give good performance at full throttle. Battery will also get hot or get puffed.  

Getting good time out of quad is tricky as on a very efficient motor, prop, battery ( c rating) if you put bigger Battery then weight of the quad increases. ( also one has to consider how you are flying the quad, smooth 1/2 throttle  or bumpy throttle frequently full up & down)

Hence there is no straight forward answer for increasing flight time. Consider your use of quad, as per that buy a efficient combination of motors, props & battery & keep the frame weight as low as possible.

example --> I do direct soldering of motor and ESC connections saving on connector weight. ( yes, you will have to go in such details for increasing flight time. Using Self screwing props (DJI) will save on collet weight, 2212 Motor with DJI props is a good combo, DJI props supposed to be more efficient then normal props.

hope you got basic idea... rest read a lot from net .. there is tonnes of info available.

knvshrm


taksh

@rastsaurabh
Thanks Uncle
I think i need to learn college level physics.

K K Iyer

Quote from: taksh on May 17, 2018, 07:25:01 PM
@rastsaurabh
Thanks Uncle
I think i need to learn college level physics.

@knvshrm
@taksh

Taksh, I think you are just being modest. Saw on another thread that you built a DIY TX!
Nevertheless, your reply #4 in this thread needs a relook.

Kanav, here's one way of approaching the problem:
The first rule is to start from observation instead of from opinion.
Known facts:
1. Hover time 5 min 30 sec
2. Battery is 3s 2200mah
3. Since you had earlier asked about how low a lipo can be run, you probably did not use more than 1500mah

So let us assume that 1500mah was used in say 5 minutes, or in 1/12 hour.
Or 18,000 mah in one hour.
Ie, drawing 18 amps.

At 11-12 volts, that's a little over 200 watts.

You said the quad weighs about 1kg.
Hence in hover the thrust must be 5gms per watt.

This can easily be improved to ~8gms/watt, with:
1. A larger diameter prop
2. Lower pitch
3. Lower RPM, ie, lower kv motor

To get a feel for this, look at the first post in the undernoted thread, that has half throttle data for a DT700 motor with different props.
https://www.rcgroups.com/forums/showthread.php?1594904-Efficiency-test-hexTronik-DT700-and-24-propellers-GWS-9x5x3-added

knvshrm

Thank you sir for your valuable suggestions  :salute: will do the modifications soon...
Regards

knvshrm

Sir what pitch to go for ? Right now the pitch is 4.5 will 3.8 be fine ?

K K Iyer

Doubt if you can get a prop with less pitch than 3.8"
What is the largest dia that can fit? 10"? 12"?
If you can get 12*3.8, (or say 11*4) you should consider using a 2s lipo of 3300mah (which should weigh about the same as your 3s 2200)
But without a wattmeter and a homemade thrust gauge, this will be just tukka or guesswork...

Meanhile, you can add payload to check how much it reduces the duration.
Eg, your 2200 weighs 200gms and gives 5 minutes 30 sec.
Add 200gms payload and check duration.
It will probably be more than half of what you are getting.
If so, all you need is a larger lipo!

knvshrm

Ok sir will check and let you know.