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PG. 11
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You can operate batteries down to about 2.4 Volts (for two in series, 1.2 Volts on the graph below).
Remove the batteries and measure each of them. If your combined battery voltage is less than 2.4
Volts, replace the batteries.
You may also use alkaline AA batteries such as Duracell Coppertop. They will not last nearly as
long, especially at low temperatures, but will likely be adequate for several weeks at 10-minute
interval.
When replacing batteries use only fresh batteries. Do not mix battery types. If one battery differs in
type or charge level from the other and the miniDOT Clear Logger runs them to full discharge, then
one battery may leak. SEE SECTION 3.4 FOR CAUTION ON BATTERY PLACEMENT.
Error on the side of caution when planning your deployment.
The recommended battery is the Energizer L91 lithium battery. For more information including the
performance at low temperatures, then click the link:
http://data.energizer.com/PDFs/l91.pdf
The figure to the left gives a general idea of
terminal voltage vs. lifetime. Service life in
hours is incorrect since miniDOT Clear
Logger draws far less than 50 mA
continuously, but the general shape of the
voltage vs. time gives an estimate of life
remaining. This plot is taken from the
manufacturer’s specification. The plot is for a
single battery. The miniDOT Clear Logger
halts operation at a total of 2.4 Volts.
C O I N C E L L B A T T E R Y L I F E
The miniDOT Clear Logger uses a coin cell battery for backup of the clock when the power is
switched off. This coin cell battery will supply many years of clock operation. Should the coin cell
battery discharge, then it must be replaced by PME. Contact PME.
