013-015-B2 Rev C
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4. Operating Temperature
4.1 Operating range
The AlphaCap-665 operating range is -40°C to +65°C (-40°F to +149°F).
4.2 High-temperature shutdown
A temperature of +65°C will trigger a high-temperature shutdown. Normal holdup and charging functions will resume
when the temperature drops to +60°C (+140°F). In other words, there is a 5°C (9°F) hysteresis.
4.3 Ambient versus case temperature
In most cases, the temperature limitations are based on the ambient temperature. Because a fully charged Alpha-
Cap-665 dissipates very little heat, the case temperature is assumed to be equal to the ambient temperature.
4.4 Temperature effects
4.4.1 Holdup duration
The holdup duration decreases as the temperature increases. The power output also affects the holdup duration,
making this a 3-dimensional analysis.
4.4.2 Capacitor life expectancy
High temperatures decrease the life of an AlphaCap-665, for example:
350 W load at 25°C (77°F)
11 s of holdup after 10 years.
350 W load at 45°C (113°F) 8 s of holdup after 10 years.
350 W load at 55°C (131°F) 4 s of holdup after 10 years.
4.5 Electrical
The AlphaCap-665 is designed with a single connector for input and output for a single “+” and “-“ connection to the
–48 Vdc system bus similar to a battery.
