User's Guide

12V Calibration
The 12V voltage is measured using the incoming voltage that powers the OVMS. You can
calibrate it using…
config set system.adc factor12v <factor>
The <factor> has to be calculated using:
oldFactor * (displayedVoltage / actualVoltage).
● oldFactor is the old value set. If you have not changed it yet it is 195.7
● displayedVoltage is the Voltage as displayed by the OVMS.
● actualVoltage is the Voltage as measured by hand using a voltmeter.
The voltage is read once per second and smoothed over 5 samples, so after changing the
factor, wait 5-10 seconds for the new reading to settle.
The initial 12V reference voltage (= fully charged & calmed down voltage level) on startup &
after reset can be set by
config set vehicle 12v.ref <voltage>
The default reference voltage is 12.6. The value will be updated automatically if your vehicle
supports the v.e.charging12v flag.
The 12V alert threshold can be set by
config set vehicle 12v.alert <voltagediff>
The 12V alert threshold is defined by a relative value to the 12v reference voltage with a
default value of 1.6. If the actual 12V reading drops below 12v.ref - 12v.alert, the 12V
alert is raised.
Related metrics:
Metric
Example value
Meaning
v.b.12v.current
0.6A
Momentary current level at the 12V battery
v.b.12v.voltage
13.28V
Momentary voltage level at the 12V battery
OVMS v3 User Guide Page 21 / 86