5.8. Effect of temperature
on lifetime
Sunica.plus is designed as a
twenty year life product but, as
with every battery system,
increasing temperature reduces
the expected life. However, the
reduction in lifetime with
increasing temperature is very
much lower for the nickel-
cadmium battery than the lead
acid battery.
The reduction in lifetime for both
the nickel-cadmium battery and,
for comparison, a lead acid
battery is shown graphically in
Figure 6.
In general terms for every
+ 10°C (+ 18°F) increase in
temperature over the normal
operating temperature of + 20°C
to + 25°C (+ 68°F to + 77°F), the
reduction in service life for a
nickel-cadmium battery will be
20 % and for a lead acid battery
will be 50 %. In high temperature
situations, therefore, special
consideration must be given to
dimensioning the nickel-cadmium
battery. Under the same
conditions, the lead acid battery
is not a practical proposition due
to its very short lifetime.
14
Figure 6 - Lifetime reduction with temperature
Temperature
Percentage of + 25
°
C (+ 77
°
F) lifetime
Lead acid
Nickel-cadmium
+ 25°C
+ 77°F
0
10
20
30
40
50
60
70
80
90
100
+ 30°C
+ 86°F
+ 35°C
+ 95°F
+ 40°C
+ 104°F
+ 45°C
+ 113°F
+ 50°C
+ 122°F
+ 55°C
+ 131°F