Compass motor calibration

when I try to do the compass motor calibration, I press start and raise the throttle up to about 60% for 5 seconds. But the blue and red lines don’t rise at all. I see a message that says new values have been stored:
x:0 y:0 z:0

Does anyone know what I’m doing wrong here. In the past I have been able to successfully calibrate it.

just want to add that I have gone into the config tab_standard parameters and it is set to analog voltage and current for battery monitoring and A12 for current sensing pin

Can you tell me which versions of APM Planner 2.0 you are using OS and ArduCopter version.

Also post a log?

In the meantime , are you checking that both voltage and current are displaying correctly in the InfoWindow?

I was running the compass mot without props. It hadn’t dawned on me for some reason that the motors wouldn’t draw comparable amps without props.
all set now thanks.

Now that I figured that out, my inline power analyzer has come to life as well. It looks like my motors are drawing more power than I expected. Do you think that is due to the larger props? currently using 15x5 props

you can test compass mot, by rotating the prop position clockwise and turning them upside down. It then pushs the copter into the ground instead of taking off … and_motors

Bigger props will pull more amps. (ie more power)

That’s what I did. I caught the tutorial from the ardupilot site. Now I just have to wait till morning to run the compass mot. Those 15" props are extremely loud. I routinely hear the people in the apartment next to mine snoring through the walls, so running the motors w/props on will likely scare the crap out of em.

Regarding the amps pulled by the props;
If my power analyzer shows that I am regularly going above 30a and going as high as 40a or even a little above, will setting up current limiting be sufficient? Or should I just bench my quad until I have some 40 or 50a ESCs.(currently 30a ESCs)

You say you are pulling 120A max? While doing a compass mot? Steady state. There’s no current limiting I know off and if you can set it in the ESC it will probably have disastrous results to the control algorithms. I’d suggest getting bigger ESCs.

I never raised the throttle above 2/3 throttle and I saw the power analyzer go over 40a. But I was thinking that each motor esc was the recipient of those 40a. I guess that number is actually divided by 4 motors. Is that right? I’m still somewhat new to the science of drone technology and I still find myself stumbling occasionally.
My ESCs did get quite hot. Fortunately, I didn’t burn out a motor. I’m starting to think I should just order some 10" or 12" props and shelf the 15" props until I can afford to get a set of quality 60a ESCs. I imagine the amps pulled by the smaller props will be significantly less. When I bought the motors from hobby king, their was minimal data regarding the conditions they are suited for. At the time, the listing just said 10 to 15" props & a 30a esc. Still, I should have looked into it.

The motors are in parallel to the battery so the current from the battery is the sum of the current in each motor. So you will be good with approx 10A in each motor.

They always get hot. As they need airflow to stay cool and 10A is still high current.
If you have further quad questions stick then in the other forum topic. Thanks

some info that I found on the topic of current limiting.
@ … e-scaling/

Copter > Current Limiting and Voltage Scaling
Current Limiting and Voltage Scaling
Copter includes current limiting in order to protect the battery from damage and voltage scaling to compensate for the voltage drop as the battery is depleted. Both of these features require the vehicle to have a Power Module or other voltage and current monitor.
Current limiting and voltage scaling were introduced in Copter 3.3.
Contents [hide]
1 Current Limiting
2 Voltage scaling
Current Limiting
This protection automatically drops the throttle to as low as 60% of full throttle in order to limit the current requested from the battery. This can be useful to protect the battery from damage.

To enable the feature, set the MOT_CURR_MAX parameter to the desired limit in amps (or “0” to disable this feature).


If the measured current exceeds this limit the maximum throttle will be reduced to a safe level in 1 to 5 seconds (depending upon how far over the limit it is). Because the limit can be exceeded for short periods of time, the limit should be set somewhere between the battery’s burst limit and it’s absolute upper limit.

Voltage scaling
If enabled, this feature will increase the roll, pitch and yaw control gains to compensate for the voltage drop as a battery is depleted. This is helpful in that it helps ensure the vehicle’s attitude controls do not degrade as the battery weakens.

To enable set the MOT_THST_BAT_MAX to the battery’s full charge voltage (i.e. 12.6 for a 3S battery). Gains will be scaled to attempt to maintain the attitude control response seen at full charge.

Set MOT_THST_BAT_MIN to the minimum battery voltage the vehicle would normally experience. The gains will not be scaled up any more as the voltage falls below this level. Setting this to the battery failsafe voltage is a good start.


When a 4S 5200mAh battery costs only $22 you don’t worry about current limiting as much. The $150 Solo batteries I’d be more concerned. … duct=56840

In your case I don’t think you’ll need to be concerned with that feature.

The voltage scaling I haven’t used. Be interesting to see how effective that is. Probably just different.

Sent from my iPad using Tapatalk