Precision Measurement Engineering, Inc.
(760) 727-0300
www.pme.com
10
The Low Drain Performance plot below gives an estimate of terminal voltage for both lithium
and alkaline batteries. 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. Don’t mix battery types. If one battery
differs in type or charge level from the other and the miniDOT Logger runs them to full
discharge, then one battery may leak.
SEE SECTION 3.4 FOR CAUTION ON BATTERY
PLACEMENT.
Err 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 below gives a general idea of terminal voltage vs. lifetime. Service life in hours is
incorrect since miniDOT 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. Double the voltages shown to
give the terminal voltage as measured in the picture above. The miniDOT Logger halts
operation at a total of 2.4 Volts.
