Onset HOBO - Batteries

Chapter 3: Understanding the logger
HOBO Energy Logger Pro User’s Guide 11
Memory
The logger contains 512K bytes of very durable, high-capacity, non-volatile Flash memory, which stores data even
if power runs out. This allows for data retention even when the batteries become depleted or are removed.
Up to 10K of this memory is used to store the launch configuration and deployment notes, leaving at least 502K
bytes for data storage. HOBOware Pro automatically estimates how long the logger will record data before the
memory fills up, based on the logging interval and the number and type of sensors connected. This is called the
logging duration.
Adding sensors or logging the internal battery channel decreases the logging duration; increasing the logging
interval increases the logging duration.
For most applications, it is battery life, not memory capacity, that limits the logging duration. The following table
shows the expected run time for several logging intervals based on the total number of bits in place, which is
determined by adding together the bits per sample for each sensor measurement parameter in your system. For
example, a HOBO Energy Logger Pro with the following sensors is using 56 total bits.
Sensor
Bits per
Sample Total bits
1 temperature sensor X 8 = 8
1 wind speed sensor X 16 = 16
2 temperature sensors X 16 = 32
Total number of bits 56
At a logging interval of 5 minutes, the logging duration for a logger using 56 bits would be approximately 250 days.
(Refer to the sensor manual to determine the number of bits each type of sensor uses.)
Batteries
The HOBO Energy Logger Pro requires eight 1.5V AA batteries. The logger is shipped with eight alkaline batteries,
and is also compatible with enhanced alkaline batteries and lithium batteries (Li/FeS
2
).