Calibrate Amperes (Amperes per Volt) in Battery monitor settings without Amp Meter

Basic, only for dummies…

I do not garantee this is the safest and accuratest way, but sometimes, with small light drones, like my test drone, it’s difficult to use the Ampmeter tool, values displayed fluctuate too much.

This example for 3S 11.1V 3300mAh battery

  1. Full charge your battery.
  2. Connect to MP, select INITIAL SETUP…Optional Hardware…Battery Monitor and type your battery capacity (3300mAh).
  3. Look at the value in the field Amperes per Volt (default is 17) and remember it.
  4. Using a telemetry solution, like yaapu, you will see the capacity indicated in MP (point 2 above) 3300mAh and the capacity used (0 before the flight).
  5. Proceed to a standard flight (loiter mode) and wait your battery reaches the defined lower limit in voltage (10.5V in my case).
  6. Land.
  7. Look at the Remote Control display and note the % and mAh of battery remaining. In my example, with Amperes per Volt set to 19, I read 1.97mAh in the script display, and 40% battery remaining.
  8. Full charge again your battery and look at the charger’s display how much Ah were injected in the battery, in my example 2.28Ah.
  9. Compare the value of point 7 (1.97Ah) with the “real” value of point 8 (2.28Ah). If this last value is higher at the one displayed in the sript display, increase the Amp per Volt value until you reach the “real value”, and proceed to a new flight. In my case Amperes per Volt needs to be set to 23.

Hope it helps someone.

This simple ratiometric procedure has been around a long time.

  1. New amp/volt=old amps/volt*charged mah/logged mah

Happy for you, can you give me the linkin the wiki? For me in the Wiki you have only this, this is another way to calibrate Amperes…

Wiki? This is self-explanatory, it’s ratiometric… You would follow the same procedure you outlined but I would obtain the “logged mah” from the flight log. I assumed everybody uses this method.

Sorry to post this, I will change the title: Only for dummies, if you are too clever, don’t waste your time reading this post…

The limit of this method is that you will obtain an average value and since non HAL effect Ampère sensors do not work well with low values you can risk of having wrong measurement while generally it is important to have a good measure of high ampères values.

I suggest to use a power analyser like this one :

It can be useful in a lot of circontances and IMO worth each cents it costs.

I use this one, almost the same I hope!

As I said I use a very small drone with 2212 low power motors. But with another Tarot 650 with larger motors, no problem to calibrate with the Ampmeter. You’re right, I just get the average value, but in this case, better than just looking at the voltage value.

I plug a battery on the output and charger on the input so i can set it to charge at 5A and use that to calibrate the sensor.

it works with a charger on the output if it can discharge fast enough.