search

kamilsss655 / ESPRI

ESPRI (ESP Radio Interface) project providing extended functionalities to ham radios
Apache License 2.0
122 stars 6 forks source link

[FEATURE] V2.2 board battery measurement #50

Open kamilsss655 opened 3 months ago

kamilsss655 commented 3 months ago

Is your feature request related to a problem? Please describe.

New 2.2 boards support battery measurement.

Describe the solution you'd like

Battery voltage is measured every couple of minutes and the reading is available in About page in frontend app. Voltage divider is only powered during the measurement and then turned off via MOSFET to conserve power.

KDMcMullan commented 2 months ago

From the schematic, it looks like it's already added. HOWEVER, your divider is 200k total. That's drawing like 8.2 / 2e5 = 41uA. That portion of the circuit should not deplete a 2200mAh battery for at least 2.2 / 4.1e-5 = c. 6 years. I could be completely mad, but I'm not sure it's worth the effort.

kamilsss655 commented 1 month ago

There is no need to drain battery all the time, if the voltage measurement can be taken in less than a second every few minutes.

Moreover you should note that there are other elements already on the board that deplete the battery:

  1. The LDO quiescent current
  2. Audio input voltage divider

The board is designed to be battery efficient. This is also the reason this particular ESP host board has been selected, as it offers good price to LDO quiescent current ratio. And in my book the more efficient the better.

KDMcMullan commented 1 month ago

I completely agree. There's no need. But with the calculated drain being so minimal, it's not worth the extra effort of adding even a 10c transistor. the other two points are void for these purposes: the poster is enquiring specifically about only powering the voltage divider during measurement. They don't ask about LDO quiescent current, nor the audio input PD. Out of curiosity: are either of these bypassed with the proposed FET?