ADC A1 reading out of range

Hello,

I am using Navio2.
When I run the ADC example I can see strange readings on the A1 channel (servo rail voltage):
A0: 5.1960V A1: 18.3260V A2: 1.4720V A3: 0.0000V A4: 0.0180V A5: 0.0260V
However I can measure the servo rail voltage with a volt meter and it is 5.01V.

From the example I can see that the ADC value is divided by 1000 to get the voltage level, so for 18.326V the ADC value must have been 18326, which seems to be wrong for a 12-bit ADC.
Am I missing something?

My Navio2 seems to be OK and up-to-date:
pi@navio:~ $ emlidtool
emlidtool version: 1.0.8
Vendor: Emlid Limited
Product: Navio 2
Issue: Emlid 2018-06-05 831f3b08594f2da17dccae980a2e3659115ef71f
Kernel: 4.14.95-emlid-v7+
RCIO firmware: 0xb09979ae
2019-03-09 13:00:17 navio root[20288] INFO rcio_firmware: Passed
2019-03-09 13:00:17 navio root[20288] INFO adc: Passed
2019-03-09 13:00:17 navio root[20288] INFO pwm: Passed
2019-03-09 13:00:17 navio root[20288] INFO rcio_status_alive: Passed
2019-03-09 13:00:17 navio root[20288] INFO lsm9ds1: Passed
2019-03-09 13:00:17 navio root[20288] INFO gps: Passed
2019-03-09 13:00:17 navio root[20288] INFO mpu9250: Passed
2019-03-09 13:00:17 navio root[20288] INFO ms5611: Passed
emlidtool -h to get more help
pi@navio:~ $ emlidtool rcio check
Nothing to update! You are using the newest firmware.

Any ideas are welcome.

Thanks,
Csaba

A post was merged into an existing topic: Power Module Battery Voltage/Current Scalers