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PG. 10
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number of files grows large into the thousands the miniPAR Logger may suffer decreased battery life
or other performance problems. Please, at the earliest convenient time, copy the recorded files to a
HOST computer and delete them from the
miniPAR Logger’s SD card. Also, do not use the miniPAR
Logger to store files unrelated to the miniPAR Logger’s operation.
C L E A N I N G T H E S E N S O R
Contact Li-Cor for instructions for cleaning the PAR sensor. The white pressure housing and black
end cap can be gently scrubbed.
A A A L K A L I N E B A T T E R Y L I F E
Alkaline batteries will perform slightly worse than lithium, especially at low temperatures. Alkaline
batteries are superior to lithium in one way; you can determine how much battery life remains by
measuring the battery terminal voltage. For short deployments of a month or two, then alkaline
batteries will provide adequate performance. For longer deployments, or for deployments in cold
environments, then substitute lithium batteries.
A A L I T H I U M B A T T E R Y L I F E
The miniPAR Logger consumes battery power mostly from the measurement of PAR and
temperature, but also a small amount from simply keeping track of time, writing files, sleeping, and
other activities. The following table shows the approximate endurance of the miniPAR Logger when
powered by the Energizer L91 AA lithium / ferrous disulfide batteries:
Sample Interval (Minutes)
Main AA Battery life (Months)
Number of Samples
1
1
50K (approx.)
10
>12
50K (approx.)
60
>12
25K (approx.)
Keep a general record of the miniPAR Logger’s number of samples. It is not possible to accurately
tell the charge state of a lithium battery by measuring its terminal voltage. If you have a general idea
of the number of samples already obtained on a battery, then you can make an educated guess as
to how many more samples remain.
The numbers in the table above are, at the time of this writing, based upon extrapolations of testing
current demanded from batteries. The 1-month performance at 1 minute is very likely. Performance
at longer sample intervals will be much longer, but how long is difficult to predict. In any event, these
AA batteries are easily available and relatively inexpensive compared to the cost of the miniPAR
Logger. PME suggests you replace the batteries often, especially before any long (months)
measurement deployments.
