Hello,
Thank you for contacting Teltonika Crowd Support.
Please be advised that it is possible to monitor your spare 24VDC battery using a TRB141. We would recommend that you use the ADC input to read your 24VDC battery voltage rather than the isolated input as the isolated input is a digital input as opposed to ADC input which is an analogue input and supports analogue input voltages of between 0 - 30 V. Using ADC input for monitoring will enable you to view the 24VDC battery voltage in real time.
Isolated input will either show high level if voltage coming from the battery be in the range of 7.3-71 V and low level in case voltage level range is 0-7.3 V. Meaning that you will not see voltage level in real time, and you can only use isolated input as the indication that battery's voltage level dropped below 7.3V. And that could be used as an alert when battery got discharged and no longer have the needed voltage level to power up equipment.
The ADC value can be viewed by accessing the TRB141's WebUI and navigating to Services > Input/Output > Status and check for Analog Input state. The ADC value (Analogue Input) can also be read via CLI or SSH using the command below:
cat /sys/devices/qpnp-vadc-8/mpp4_vadc
In order to convert the ADC value into volts, it should be divided by 126582
Further details could be found using the links below:
https://wiki.teltonika-networks.com/view/TRB141_Input/Output#ADC_.28Analog_Input.29
Additionally you may make use of the I/O Juggler to create automated rules that perform certain actions based on certain input states. More information about I/O Juggler could be found in the link below:
https://wiki.teltonika-networks.com/view/TRB141_Input/Output#I.2FO_Juggler
Warm regards
Wesley