Hach SIGMA 900 - Manual (Page 46)

Page 46
Batteries and Chargers 8544apdx_batteries.fm
Appendix B
Nickel-Cadmium Batteries
Nickel-cadmium batteries provide superior power capabilities when used at
low temperatures. They also perform a higher number of charge/discharge
cycles than lead-acid batteries.
Maintenance
Nickel-cadmium cells are of a sealed construction. They contain no free
electrolyte, and in most cases require no service or maintenance other
than recharging.
Note: The use of chargers other
than those provided by the
manufacturor for use with these
batteries is not recommended and
may damage the battery or shorten
its life. Charging
Charge new nickel-cadmium batteries prior to use due to their self-discharge
rate.
Nickel-cadmium cells are designed to be fully charged using a nickel-
cadmium battery charger within 14 to 16 hours. Do not exceed 16 hours or
you may damage or shorten the life of the battery. The charge rate is 400 mA
dc.
Storage
At room temperature, the self discharge rate of nickel-cadmium batteries can
be as high as 2% per day. When charged cells have been stored for a long
period of time, or at an elevated temperature, a change starts to take place in
the negative probe. The structure changes so that it is less reactive than a
fresh cell. This structure will return to normal after one or two
charge/discharge cycles. Batteries that have been stored for extended
periods of time (longer than one week) should be fully charged prior to use.
Nickel-cadmium cells can be stored for extended periods of time, in either a
charged or discharged condition, without significant degradation in their
performance. However, after long storage periods, the battery pack may
require a few charge/discharge cycles to restore its full capacity.
Table 3 Lead-Acid Battery Storage Recommendations
Storage Temperature
Maximum Recommended
Storage Time
0 to 20 °C 12 months
21 to 30 °C 9 months
31 to 40 °C 5 months
41 to 50 °C 2.5 months
Table 4 Nickel-Cadmium Battery Storage Recommendations
Storage Temperature
Maximum Recommended
Storage Time
20 to 30 °C 9 months
30 to 40 °C 5 months
over 40 °C 3 months