Specifications

Section 1. Installation and Maintenance
1-6
BLACK
RED
WHITE
6V 7AH
LEAD ACID
BATTERY
6V 7AH
LEAD ACID
BATTERY
LEAD ACID BATTERY REPLACEMENT
--
++
FIGURE 1.3-2. Lead Acid Battery Wiring
Monitor the power supply using CRBasic keyword Battery (Section 7.6).
Users are strongly advised to incorporate this instruction into their data
acquisition programs to keep track of the state of the power supply. If the
system voltage level consistently decreases through time, some element(s) of
the charging system has failed. The keyword Battery measures the voltage
internal to the CR3000, not the voltage of the lead acid battery. The measured
voltage will normally be about 0.3 V less than the voltage at the internal or
external 12 V input. This voltage drop is on account of a Schottkey diode.
External power sources must be disconnected from the CR3000 to measure the
actual lead acid battery voltage.
TABLE 1.3-2. CR3000 Rechargeable Battery and AC Transformer
Specifications
Lead Acid Battery
Battery Type Yuasa NP7-6
Float Life @ 25
o
C 3 years minimum
Capacity 7.0 amp-hour
Shelf Life, full charge 6 months
Charge Time (AC Source) 40 hr full charge, 20 hr 95% charge
Operating temperature -15°C to 50°C charge
-20°C to 60°C discharge
AC Transformer
Input: 120 VAC, 60 Hz
Isolated Output: 18 VAC 1.11 Amp
There are inherent hazards associated with the use of sealed lead acid batteries.
Under normal operation, lead acid batteries generate a small amount of
hydrogen gas. This gaseous by-product is generally insignificant because the
hydrogen dissipates naturally before build-up to an explosive level (4%)
occurs. However, if the batteries are shorted or overcharging takes place,
hydrogen gas may be generated at a rate sufficient to create a hazard.
Campbell Scientific makes the following recommendations: