3 operating conditions, 4 capacity – Alpha Technologies AlphaCell SMU-HR User Manual

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745-680-B2-002, Rev. B

1.3 Operating Conditions

Because SMU-HR batteries, which are valve regulated and virtually sealed, do not give off

perceptible amounts of gas under normal operating conditions, they can be installed in the

same environment where people live and work.

Acceptable ambient operating temperature: -40ºF to 131ºF (-40ºC to 55ºC)

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Ideal ambient operating temperature: 68ºF to 77ºF (20ºC to 25ºC)

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Ambient humidity: ≤ 95%

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Operating room or area: ventilated and not fully sealed

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1.4 Capacity

Battery capacity is rated in Ampere hours (Ah) and is the quantity of electricity that can be

supplied during discharge (See Table 1-1).
The actual capacity is related to the utilization ratio of the active positive and negative

materials within the battery. The utilization ratio is influenced by the depth of discharge, the

structure of the battery, and the manufacturing technology. During normal usage, the factors

that influence the actual capacity are discharge rate, depth of discharge, end voltage, and

temperature.

The higher the discharge rate, the lower the available capacity.

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As batteries get colder, the available capacity is reduced. This is related to the kinetics of

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the electrochemical reactions and the resistivity of the electrolyte (See Fig. 1-1).

NOTE:

Although the battery can be operated at temperatures below 5ºF (-15ºC), the capacity and ability to

discharge will be dramatically decreased. Similarly, temperatures approaching 122ºF (50ºC) will increase

water loss and corrosion of the plates, resulting in a shorter battery life.

1.0

Introduction, continued

Fig. 1-1, Available Capacity vs. Ambient Temperature

Capacity (%)

Ambient Temperature (ºC)

-40

-30

-20

-10

100