Chapter 7 _____________________________________________________________ Technical Data
VAISALA _______________________________________________________________________ 171
Solar Cell
When the solar cell is used as an external power supply, a few things
should be kept in mind:
- Always use solar cell in combination with lead battery.
- To achieve the highest possible efficiency, a 6 to 8 V solar cell is
recommended.
NOTE
You can use a 12 V solar cell, however, half of the delivered energy
is lost as heat in the linear charger regulator.
Lead Batteries
The charger is capable of charging from 1.2 to 24 Ah, 6 V lead acid
batteries. There is room for one 1.2 Ah or 1.3 Ah battery in the logger
battery compartment. If larger capacity is required, additional batteries
must be connected to the POWER connector terminals GND and
+BATT. Internal and external batteries can be present at the same
time; they are essentially paralleled. For protection, an automatic self-
recovering fuse is used.
CAUTION
The battery protection fuse may trip if internal and external batteries
have very different charge states when connecting them. This is due
to current flowing from one battery to the other. This condition
ceases, when the battery voltages reach a balance after one or several
trip-recover cycles.
To be able to efficiently charge the lead battery, the charger must
know the total capacity of the connected lead batteries. This capacity
setting is done with the command:
battery
[capacity]
Where capacity is the battery capacity in Ah. This value is also saved
as a static parameter and is not lost if QML102 is reset or unpowered.
CAUTION
If too large of a capacity value is used, the battery may be
permanently damaged due to excessive charge current.
