LibrePilot Forum

General Category => General Discussion => Topic started by: startrek66 on January 30, 2017, 07:57:08 am

Title: Current consumption
Post by: startrek66 on January 30, 2017, 07:57:08 am
Someone measured or knows how much current a GPS module with external magnetometer? I noticed that when I use the GPS in flight the flight times were reduced by 30%.
Title: Re: Current consumption
Post by: f5soh on January 30, 2017, 08:40:01 am
I really doubt the GPS+Mag current drawn will reduce the autonomy by 30%. :)

You may need to search in other direction like flight style, battery...
Title: Re: Current consumption
Post by: TheOtherCliff on January 30, 2017, 05:23:57 pm
Is there a noticeable oscillation?  Do the motors get hotter?

If either is true, you may need to reduce a PID somewhere to get rid of the oscillation.

Even without a visible oscillation there can be large invisible oscillations that are so fast that the quad doesn't visibly change bank angle.
Title: Re: Current consumption
Post by: startrek66 on January 31, 2017, 07:02:27 am
Is there a noticeable oscillation?  Do the motors get hotter?

If either is true, you may need to reduce a PID somewhere to get rid of the oscillation.

Even without a visible oscillation there can be large invisible oscillations that are so fast that the quad doesn't visibly change bank angle.
I do not see oscillations. the quadcopter  is really stable and use basic pid unmodified. I had tried to measure the flight time indoors because I was pretty convinced that the cause could be the battery performance by little ambient temperatures above 0 degrees Celsius. But even indoors the flight time is decreased by 20%. The tests I made them on two batteries with the same capacity. I should be able to measure the internal resistance of the battery to see if it may be the characteristics deterioration, how to do though?
Title: Re: Current consumption
Post by: startrek66 on February 05, 2017, 12:43:26 am
I really doubt the GPS+Mag current drawn will reduce the autonomy by 30%. :)

You may need to search in other direction like flight style, battery...
I measured the current consumed with telemetry to 12.6 mW, gps receiver module on and rx on. The current consumption is 240 mAh. I expected less. It is a normal value?
Title: Re: Current consumption
Post by: hwh on February 05, 2017, 01:29:13 am
240 sounds reasonable to me.   My revo pulls 120-140mA, a random gps sitting here pulls 70-90mA, and last time I remember checking a tiny sat receiver pulled about 20 or 30mA.   Even using all the low end readings that would be 210 mA.

Compared to the large currents pulled by the motors it's nothing.
Title: Re: Current consumption
Post by: startrek66 on February 06, 2017, 08:49:36 pm
240 sounds reasonable to me.   My revo pulls 120-140mA, a random gps sitting here pulls 70-90mA, and last time I remember checking a tiny sat receiver pulled about 20 or 30mA.   Even using all the low end readings that would be 210 mA.

Compared to the large currents pulled by the motors it's nothing.
Thanks for information