
Section 1. Installation and Maintenance
1-12
1.10.1 Desiccant
The CR800 is shipped with desiccant to reduce humidity. Desiccant should be
changed periodically. To prevent corrosion in uncontrolled or condensing
atmospheres, the CR800 must be placed inside a weather tight instrument
enclosure with desiccant. Do not completely seal the enclosure if lead acid
batteries are present. Hydrogen gas generated by the batteries may build up to
an explosive concentration.
1.10.2 Replacing the Internal Battery
Misuse of the lithium battery or installing it improperly can
cause severe injury. Fire, explosion, and severe burn
hazard! Do not recharge, disassemble, heat above 100°C
(212°F), solder directly to the cell, incinerate, nor expose
contents to water.
The CR800 contains a lithium battery that operates the clock and SRAM when
the CR800 is not powered. The CR800 does not draw any power from the
lithium battery while it is powered by a 12 VDC supply. In a CR800 stored at
room temperature, the lithium battery should last approximately 10 years (less
at temperature extremes). Where the CR800 is powered most or all of the time
the lithium cell should last much longer.
While powered from an external source, the CR800 measures the voltage of
the lithium battery daily. This voltage is displayed in the status table (Section
1.6) A new battery will have approximately 3.6 volts. The CR800 Status
Table has a “Lithium Battery” field. This field is either “True” (battery is
good) or “False” (replace battery). If the lithium cell is removed or allowed to
discharge below the safe level, the CR800 will still operate correctly while
powered. Without the lithium battery, the clock will reset and data will be lost
when power is removed.
A replacement lithium battery can be purchased from Campbell (part number
13519). Table 1.10-1 lists the specifications of the battery.
Table 1.10-1 CR800 Lithium Battery Specifications
Model Tadiran TL-59025 (3.6 V)
Capacity 1.2 Ah
self discharge rate 1%/year @ 20°C
Operating temperature range -55°C to 85°C
The CR800 must be partially disassembled to replace the lithium cell.
Figures 1.10-1 to 1.10-5 illustrate how to disassemble the CR800. Reverse
these steps to reassemble the CR800.
CAUTION
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