User's Manual

DRAFT TrimTrac 1.5 Technical Manual v0.3ab 41
fixes and transmitting or receiving messages both above and below this range,
however, such operation is neither specified or guaranteed by Trimble or type
approved.
In practice, the limiting factors in any battery-powered device in terms of
temperature ranges are the batteries themselves. The capacity of alkaline batteries
is, for instance, severely compromised when subjected to high temperatures. The
TrimTrac 1.5 will survive when subjected to temperatures as high as +105
degrees C; however, alkaline batteries would likely be damaged and become
unusable after being subjected to this elevated temperature. Conversely, low
temperatures will increase the internal resistance of alkaline batteries and a
voltage drop commensurate with the low temperatures will be observed.
The NiMH battery in the Vehicle Adapter or Control Module has a wider
operating range than alkaline or LiION batteries, but it too will suffer from
temperature extremes. In particular, the charge capacity and cycles of a NiMH
battery will be decreased substantially when subjected to high temperatures. At
least they will not explode or catch fire when their rated temperature
specifications are exceeded like some LiION batteries.
Low temperatures do less permanent damage to batteries than high temperatures.
Generally, a battery subjected to low temperature will stop working, but may
recover once unit temperature is brought back to normal.
All battery life estimates assume that the batteries are at normal temperature (20
degrees C), that they have never been subjected to temperature extremes either
high or low, and, in the case of the Vehicle Adapter or Control Module NiMH
battery, are fully charged and have never been completely and fully discharged.
Vehicle Adapter or Control Module Battery Charging
The internal stand-by battery in the Vehicle Adapter or Control Module should
never be allowed to fully discharge. Even if the Vehicle Adapter or Control
Module is left uninstalled and unused, it should be connected to a 12 VDC power
supply no less frequently than once every 90 days to recharge the internal stand-
by battery. A good battery will reach full charge in approximately 3 hours.
GPS Reception Problems
Even though the TrimTrac 1.5 uses enhanced GPS sensitivity technology, it is still
advisable to position the device or the optional external GPS antenna with as clear
of a view of the sky as possible. Make sure that the TrimTrac 1.5 or antenna is
reasonably positioned to receive GPS signals.
GPS Almanac Collection
When the TrimTrac 1.5 is used for the first time after being provisioned, the unit
may not have a complete or current GPS almanac. If the TrimTrac 1.5 needs to
collect or update the GPS almanac, it will do so by keeping the GPS receiver
operating in the background. This GPS almanac collection will not interfere with
the other operations of the TrimTrac 1.5.