Convert power module values to actual voltage and current

Continuing the discussion from Power Module Battery Voltage/Current Scalers:

Hello community,

we have the exact same question as in the topic linked above:

  1. What are the voltage and current scalers in the power modul (ADC A2 and A3 channels)?
    I have found a thread in the community forum about an experimental approach (estimating the current scaler from the charge, reported by the battery charger), but I think there could be a more direct answer to this.

Unfortunately the thread has no answer to this questions and digging through the documentation and other thread also didn’t provide an answer.

To our understanding there should be simple factor which we could use to convert the values from adc measurements which are between 0 and 5 V to the the actual value for our battery between 0 and 16.8 V and the current between 0 and 90 A.
We might be able to calibrate the voltage value ourselves but that seems just like a hassle and inaccurate.
Any other solution or known conversion factors?

Thanks in advance.

Hi @johannes.hubert,

The power module outputs the 5V voltage to Navio2 ADC, it hardly can get readings directly from the battery.
There is no fixed conversion value since every power module is slightly different.
To calculate a conversion factor, I’d recommend you to measure battery voltage and current and divide the measured values by the ADC voltages.

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I still think that EMILD should (be able to) tell us at least the nominal conversion factor of their own power module.
I really do not understand what makes answering this question so difficult.

Hi @csmolnar,

I hardly can provide you with the exact value, as different units may have slightly different coefficients. However, you can configure the power module in the Mission Planner to monitor battery voltage. To accomplish it, you can try the following multipliers:

  1. Voltage divider: 11.3

  2. Amperes per volt: 17.0

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