## Calculate Flight Time of LiPo Battery

Before we can calculate flight time, we need to know the average amperage the quadcopter will draw. Once we have the average amperage draw we can then calculate flight.

To calculate flight time, take the **battery’s capacity in amp hours**, then **divide** that into the **average amp draw** of the quadcopter and then **multiply** it by **60**. The **total** is the** flight time in minutes**.

For Scout, I chose a 11.1 volt 30C 3000 mAh LiPo battery. I calculated the average amp draw of Scout to be around 20 amps. This will give me a flight time of 9 minutes.

Using your calculator at what level does that leave the battery.

The calculation is based on the batteries capacity. The estimate time will leave the battery at 0mAh and the minimal cell voltage of 3.0 volts.

Realistically you would want to have maybe 200mAh left on the battery to avoid premature failure of the battery.

So before you plug the numbers in, take off 20% to 30% of the batteries mah rating. For instance for a 2650 mah lipo, you would plug in 2650 X 80% or 70%, which would give you 2120 or 1855 mah.

Why are you taking off 20% to 30% from the battery capacity?

That for safety reason, lipo cannot be empty, it will damage the battery.

How did you calculated the average current draw to be 20Amp? only the motors(Turnigy 2213) takes from 24Amp to 60Amp? Am i missing something here?

The average current draw was calculated by having Scout hover and in the air and measuring the current draw. It take around 20 amps for Scout to hover. That means each motor was drew 5 amps. The Turnigy 2213 have an operating current range of 6-15 amps.

To preserve Lipos and prolong their life you should only discharge 80% of the available amps

how you calculate average amp draw?

First your Calculator does the math correctly.

For Example for a 5500 Mah battery and an Average Draw of 30 Amps

It calculates: (6000 but leaving 500 Mah margin(left-over)

5500/1000 = 5.5 Amp Hours

5.5 X 60 = 330 Amp Minutes

330 / 30 = 11 Minutes

However, In your opening explaination you say:

take the battery’s capacity in amp hours, then divide that into the average amp draw.

What you actually need to do is:

take the battery’s capacity in amp hours, then divide that by the average amp draw.

Above, I converted to Amp Minutes and then divided by the Average Draw, you can also first divide by the Average Draw and then convert to minutes.

Hope this helps all understand what is actually being computed/calculated.

Hi,

What is the practically achievable highest flying time ever designed? Is there any ways or anyone has designed a copter which could fly more than 40-50mins. I would appreciate if you could tell me what are the hurdles for this.

Thanks,

Anil

search google and youtube. there are multirotors with hour long flight times

Dear sir,

We are use 8, 1300 kv bldc motor for multi copter and its maximum current rating is 50~60 amp and produce thrust is 1860~2400 grams, so how many mah battry is suitable for long flight time?

Pleas riply on ketantejani77@gmail.com

Dear sir,

We are use 8, 1300 kv bldc motor for multi copter and its maximum current rating is 50~60 amp and produce thrust is 1860~2400 grams, so how many mah battry is suitable for long flight time?

Pleas riply on ketantejani77@gmail.com

is there any relation with propeller length?

Yes. Your propeller size will determine current draw, which will affect flight time. For long flight times, use a low KV motor with a 4s or 6s battery and 12-13 inch propellers.

can i used the 1800 kv motor with battery of 2700mah with 2c.

Dear sir,

We are use 8, 1300 kv bldc motor for multi copter and its maximum current rating is 50~60 amp and produce thrust is 1860~2400 grams, so how many mah battry is suitable for long flight time?

Pleas riply on ketantejani77@gmail.com

Hi there,

I am a mechanical engineering student. I have compiled an entire report in drone component selection for my project and I am at the stage where I have selected the components based on my research.

If possible I would like to get the combination of components checked or reviewed by someone in the field as I am unsure about the spec sheet I have generated. If anyone is able to assist I will put forward the specs or the contact details.

Kind regards

Jameel