# High consumptions. Batteries die very fast. Not heat losses detected

Hello everybody, we are experimenting a weird problem about consumptions in our vehicle. We are taking off a quadcopter (U10 plus 80kv motor and 30 - 10.5" blades - ESC Flame 100 14S); although we are able to take off and land without problems, our batteries (two 6S batteries connected in series of 10000 mAh each one) die very fast, only a few minutes of flying in vtol. We are losing energy very fast but we did not detect any overheat at the wires or any other device. Does anyone a tip about which coould be our problem? maybe any parameter should be tune ?

Our calculus say it should able to lift without problems, the weight is 16kg, and the lift of the motors up to 40 kg (aprox).
Im open to any suggest or hint
Thanks

Tuning might help but doesn’t increase your flight time drastically (if you have a reasonable flight before). Did you monitor the vehicle’s power consumption? Perhaps some logs?
You have 12S 10Ah. U10’s have 10kg per motor at max thrust give it or take. For weight per motor is 4kg, so (I did not find the exact motor type, just assuming), just for lift off, each motor needs %50 thrust, which is 8amps for each motor, 32 amps for the vehicle. Approximately your max flight time is 10/32*60 = 18.75 minutes at most. By saying “few minutes”, how much?

Hi and thanks for replying! The specs of our motors (assuming 75% eff) are 11.8 A per motor, so 47.2A of consumptions.
The C-rate is 30C for the batteries. Extrapolating to your calculus, we should have 10/47.2*60=12.71 min , we had calculated for 18 min aprox. Anyway, we flew for 5 min, which is weird.
We have to check Qgroundcontrol+Ardupilot analysis log yet.

Why don’t you just plug those numbers into eCalc? If you did you would find it’s underpowered/overweight (~69% throttle at Hover) and should fly (hover) for ~9 minutes to 85% capacity.

Post a link to a .bin flight log and let’s see how close this prediction is.

Seems you have an underpowered (or in other words, heavy) vehicle.

The C rate is irrelevant in your case.

Why did you land after 5 minutes? Did you see something like thrust loss or you were monitoring the battery status and decide to land?

Post them in here too as @dkemxr suggested. Logs might help.

• Get a motor tester with current measurement capability.
• Divide the total weight by the number of motors.
• For that thrust find the combination motor/propeller with the least current.

Hello again!

This is a link to the logs:

Could anyone tell how can I check them by myself? Which programm/tool should I use to open .bin files?

This flight time makes sense for us. Since at 40/50% battery the drone automatically landed. Maybe QHover or QLoiter mode force to do that.

I think is a safety process when it reaches 40/50% battery capacity in Qhover/Qloiter mode

You don’t have a current monitor installed.

You have posted in the wrong thread if it’s a VTOL.

Hi! I posted here because we are using Arducopter 4.1.3, and for the current problems, I thought this was the most similar topic . Still we dont move to fixed wing mode

The logs you posted show ArduPlane 4.1.3 not Copter. Wrong thread. A 69% hover throttle may be sufficient for a VTOL. Post in the VTOL thread.

But in any case I think your basic question was answered. The performance is as expected.

Ok, thanks. I will move to VTOL thread