The state of the red Main Power cable on the Syrus can be queried with the command:
>QSSF13<
a response of
>RSSF131< connected (8-32V DC)
>RSSF130< disconnected (< 8V DC)
You can connect the ADC cable (White color cable) found in Syrus 3G & Syrus 3G Bluetooth devices to the Main Power to know the main battery’s voltage.
After connecting both cables you can use the command
>QXAAC<
the response looks like this
where vvvvv is the voltage read in milliVolts and ### is the percentage of that voltage from the max 15V
>RXAACvvvvvP###<
example:
>RXAAC13103P087<
Which corresponds to 13.1V / 87% of 15V.