How to see altitude value from flight log?

Dear Forum,

I want to see my drone altitude change during flight and battery voltage value.
Are these correct graphs?

How is possible my drone altitude goes up but drone battery goes down?

Please see flight log attached 2019-12-01 10-04-17.bin (276 KB)

Can anyone please take a look on this ,pleaase~~

Your craft has insufficient power to fly so of course the battery sags. As was explained in the other thread… Clearly 2S power is not cutting it.

Dear Dave,

Thank you soo much!! To be honest my purpose of this topic is to understand analyse flight logs.
Yes, you already explained me that battery is the problem, thank you much.

However, for I can better understand flight log, can you please explain the below graph,

Battey voltage is down, but Alt is going up ie. drone is going up. How is that possible?
And in your graph you look RCOU parameter, why?

can someone please help me out with this~
I want to fly again, but need fully understand the logs

When alt is going up, current increases. Mr. Georg Simon Ohm found out the relation with voltage 200 years ago.'s_law


1 Like

As you increase Throttle- which is Channel 3 ,(RCIn.Ch3). FC sends motors signal to increase RPM (RCOU.Ch3). RPMs on motors increase as does load on motors (Current (BAT.Curr) goes up). Due to high Current draw, voltage sags or drops (BAT.Volt). As voltage drops FC will increase RC Out to speed controllers (RCOUT.C3) to enable copter to lift off as you kept increasing throttle. This load Pulls Voltage down and FC will attempt to increase RCOut to follow your RC Input command to increase RPM. At some point battery Voltage will limit ability to fly. Even with a large enough battery you will see voltage drop over time during flight. With your too small battery the effects are amplified…

In a direct hookup from a ESC to a motor , RPMs will drop under load or lowering voltage at a certain throttle setting, You have a FC in line, that will adjust its motor signal to an ESC to compensate for this- so voltage has no direct relation to RPM as long as the battery can keep up.

Excellent description and soo detail
Thank you Sir ever so much for your time.

@Rolf, to be honest it is not such a clear from V=IR, that when alt is up than I should be up and V down

The older or weaker the battery, the higher the internal resistance of the battery (R in Ohm’s Law). The voltage drop is correspondingly greater with higher power consumption.

Please how do you plot this graph with the messages included inside the graph? I am trying to get better at using flight logs and this would be very helpful. Thanks