Campbell Scientific CR23X Micrologger - Manual (Page 238)

SECTION 14. INSTALLATION AND MAINTENANCE
14-12
14.10.2 REPLACING THE INTERNAL BATTERY
CAUTION: 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 CR23X contains a lithium battery that
operates the clock and SRAM when the CR23X
is not powered. The CR23X does not draw any
power from the lithium battery while it is
powered by a 12 VDC supply. In a CR23X
stored at room temperature, the lithium battery
should last approximately 10 years (less at
temperature extremes). Where the CR23X is
powered most or all of the time the lithium cell
should last much longer.
While powered from an external source, the
CR23X measures the voltage of the lithium
battery daily. This voltage is displayed in the
B Mode window 8 (Section 1.6) and in
response to the telecommunications Status
command (Section 5). A new battery will have
approximately 3 volts. The battery should be
replaced when the voltage drops below 2.4
volts. If the lithium cell is removed or allowed to
discharge below the safe level, the CR23X 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 Scientific or from an Electronics
store (e.g., Radio Shack). Table 14.10-1 lists
the specifications of the battery.
Table 14.10-1 CR23X Lithium Battery
Specifications
Model Sanyo CR17335 SE (3V)
Capacity 1800 mAh
self discharge rate 1%/year @ 25°C
Diameter 17.0 mm
Length 33.5 mm
Temperature range
Operating -40°C to 85°C
Storage -40°C to 60°C
The CR23X must be partially disassembled to
replace the lithium cell.
The battery is replaced as shown in Figures
14.10-4 to 14.10-6. The battery is held in place
by a band clamp. It can be removed by gently
prying the band from the sides of the battery
holder.
SANYO
FIGURE 14.10-4. Removal of CR23X back
plate and lithium battery location.
The new cell is placed into the battery holder,
observing the polarity markings on the holder.
Replace the band clamp, ensuring that both
ends snap securely into the battery holder.
SANYO SANYO
FIGURE 14.10-5. Loosening of band clamp.