Troubleshooting guide

Station ‘Low battery’ warnings
Note: This topic refers only to low battery warnings from Vue and VP2 transmitters (or what are reported as
messages similar to ‘Low battery on station #1’). Console low battery warnings are dealt with in the console
section.
Background
All modern Davis wireless transmitters (ISS; Supplementary wireless transmitters such as the Anemometer
Transmitter; and wireless repeater units) are powered in a similar fashion: The circuitry typically has three
three sources of power: a small solar panel; a ‘supercapacitor’ (‘supercap’) component; and a backup
lithium battery. (NB The 6372 and 6382 Supplementary Temp and Temp/Hum stations have no solar panel
as standard, although one may optionally be fitted.) These three power sources work together in harness as
follows:
When the sun is shining brightly then the solar panel provides power for the circuitry. Any surplus power is
used to charge up the supercapacitor, which, as a 10 Farad component, can hold a considerable amount of
charge for its size.
As night falls, the solar panel can no longer provide any power and the circuitry switches to use the
supercap as its primary power source. The supercap can hold enough charge after a bright day in summer
time (long days and short nights) to power the transmitter for the whole of the night-time. But for much of the
year, the supercap will be exhausted after a few hours of operation and the circuitry will then switch
automatically to use the backup battery as the power source. At dawn, the solar panel will start to function
again and will take over from the battery.
The transmitter circuitry is very efficient and the back-up battery will last a considerable period. Indeed even
without solar panel input (eg as in the 6372/6382 transmitters) the battery can last 6-9 months. The role of
the solar panel is effectively to extend this battery life still further, typically to 18-24 months. But nonetheless
the battery will of course eventually expire and need replacing, which is clearly when the Station ‘Low
battery’ warnings are designed to show and alert the user to the need to change the battery in the relevant
transmitter. In normal operation there is usually no need to panic when the station low battery warning
appears – typically the unit will not stop transmitting overnight for at least 1-2 weeks.
In stations with just a single transmitter then obviously there can only be one transmitter battery that needs
changing. In multi-transmitter configurations then care must be taken to read the ‘Low battery on station #1’
Prodata Weather Systems Davis Weather Stations KB - Prodata Weather Systems - 1
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