HUNTER OPERATION
SECTION 2.10
2. 10
BATI"ERY LIFE
2,10. 1 HUNTER's power control system is designed to optimise battery life by
adapting power consumption to the computer's level of activity. This
means that power consumption varies according to the level and nature
of use, making calculations of battery life slightly more complex
than usual. However, if it is known how long HUNTER will be used in
its different modes, it is possible to calculate with reasonable
accuracy the expected life of a set of batteries.
2,10.2 Battery capacity is measured in mAH (milliamp hours) and by knowing
the battery type in use, life may be calculated.
Battery capacity is affected by a number of factors including age,
charging method, ambient temperature, etc. However, the capacity
typically available from the two types of battery used by HUNTER is
as follows:
a) DISPOSABLE Duracell type MN1500 (I.E.C. LR6) capacity 900
mAH.
b) RECHARGEABLE Berec type NCC50 (I.E.C. KR 15/51) capacity 425
mAH.
Because capacity can vary significantly, the application planning
should always assume reduced available capacity. There are no firm
guidelines for this, but 50% of capacity is considered conservative.
A factor affecting apparent battery life is the "end point", or
voltage at which the battery is considered to be exhausted. Hunter
sets this end point at 4.6 - 4,8 volts for battery warning.
This value yields virtually 100% of Nickel Cadmium batteries capacity
and gives good results for Alkaline cells, but means that
manufacturer's specifications for capacity may some times be
misleading.
2.10,3 HUNTER's power consumption has three principal modes:
a) POWER SAVE 15mA
(awaiting keyboard or serial port entry)
b) OPERATING 90mA (208K)
VER.V09F
(running a program for calculation, data storage, screen updat-
ing or any operation involving continuous execution of user
program).
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