Copter 3.5 power monitor issue

Hello there, I just updated to 3.5 on my pixhawk and since this update my reported current with propulsion off is around 400 - 600A… Measured with a meter and it’s.5A… Went back to 3.4.5 and current reports normally again. I use a current limit on rig in order to not stress my battery… I’m new here so I’m not sure your typical manner of reporting bugs…

If you’re seeing ludicrous amp readings in Mission Planner, it is probably because your version of Mission Planner is quite old. Update and it will show the amp readings correctly.


I’m using 1.3.48… Is that outdated? I thought it was the stable release

Thanks for the report, this is the right place to report bugs. is what I’m using so it sounds like a reasonable number. Maybe try pushing the “Help” button and then “Check for Updates” just to be sure.
If that doesn’t fix it, have you got a dataflash log by any chance?
here’s how to download a dataflash log:

There was a reported issue in the pixhawk 2 area about this that @Michael_Oborne responded to. This is fixed in the latest beta release of mission planner.

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Awesome. As soon as I noticed this on my hardware I reverted firmware and the issue went away. I prefer to set up my hardware on stable releases and will wait for a stable MissionPlanner before going to 3.5…

I use MOT_CURR_MAX with a Mauch 200A current sensor so I was worried about this tripping during flight. Can’t be too careful.

In MP, what sensor do u choose for the Mauch 200a current sensor. Just got mine but havent installed it yet.

I believe you just pick “Other” in MP screen. Look Here:


1.3.49 is the most current MP

Wanted to confirm this is fixed with the 1.3.49 and 3.5.0

Since it was brought up, this is what works for me on my Mauch sensor. It’s dead on against my test equipment compared to the resistor based sensors.

I had same problem yesterday after install 3.5.0 on my hexa.
Always 25V on screen, and the result was a crash during autotune.
No battery alarm at 21V, and the led status was always on fix red.

I downgrade to 3.4 and the led falshing again and battery screen is ok.

Mauch sensors are pre-calibrated at the factory.
A data sheet comes with each sensor with the numbers you plug into Mission Planner’s voltage sensor section for proper readings.
If you misplaced the datasheet, just email Christian Mauch and he will provide your data.
He keeps excellent records of sale.

Now that we are at v3.5.1, try upgrading if you still see the effect with factory numbers.

I am aware he does this, that is why I went with his product in the first place (Using his BEC too)

I use plain jane PMs. After I calibrate them I am well within 200mAh of logged consumption vs charged current.

The basic process is you take a fresh battery and make a flight of 5 minutes or so, land, disarm and unplug the battery.
Charge the battery and record the mAh charged. We will call this number “CHARGED_MAH”

Now take a look at the flight logs and find the total current used. We will call this number “LOGGED_MAH”.

Next look at the BATT_AMP_PERVOLT parameter and record that number (by default its something like 17…). We will call this number “OLD_AMP_PERVOLT”

So, let’s say LOGGED_MAH was 1300Mah, and CHARGED_MAH was 1500mAh, and OLD_AMP_PERVOLT was 17.

We can use this formula:


NEW_AMP_VOLT = (17 x 1500) / 1300
NEW_AMP_VOLT = 25,500 / 1300
NEW_AMP_VOLT = 19.61

Set BAT_AMP_VOLT to 19.61 and click “Write Params”

Take a fresh battery and make another 5 minute flight.

After one or two iterations you should be well within ± 200mAh…

BTW, BATT_AMP_PERVOLT is the same thing as item #6 in the PM calibration box…