Technical data

• monitor battery temperature during charging using a thermistor placed on or
near the battery wired to an ADC input on the Wireless CPU®
Li-Ion batteries have a higher ESR (compared to Ni-Cd or Ni-MH), although this
should not be a limiting factor for peak current delivery, any battery should be
capable of at least 50% greater than the GR64 demands (~3A peak)
To determine battery life, on a full charge, the following rule of thumb can be applied:
• Standby time = Battery Capacity (mAh) / Idle current (mA)
• Call time (voice or data) = Battery Capacity (mAh) / Call current (mA)
Example 1 – Standby Time
A 600mAh rated Li-Ion battery, from fully charged (around 4.2V) to the Wireless CPU®
cut-off point (3.2V) will provide around 95% of its total charge capacity. For a
standby (idle) current of 18mA, the Wireless CPU® will typically provide
600*0.95/18 = 32 hours standby time
Example 2 – Call Time
An 1800mAh rated Li-Ion battery fully charged, transmitting maximum power on a
low-band (850/900MHz) channel may consume an average 320mA, therefore the
Wireless CPU® would typically provide
1800*0.95/320 = 5 hours 20 mins call time
Example 3 – Typical Operation
A Wireless CPU® performing periodic network data transfers and communicating
intervallic status information to its host would spend its non-active periods in sleep
mode. If the Wireless CPU® spends 30 minutes each day on call (320mA), 30 second
each hour performing housekeeping, monitoring and status tasks (110mA), and
sleeps (2.1mA) during the intervening periods, an 1800mAh rated Li-Ion battery fully
charged would typically provide
1800*0.95/([0.5hr*320]+[0.2hr*110]+[23.3hr*2.1]) = 7 days 6 hrs operation
The above examples are given for guidance, the actual battery life will
depend upon variables such as battery condition, number of previous
charge/discharge cycles, operating temperature, series resistance
between battery and the Wireless CPU®, and manufacturing tolerances
CAUTION
This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged without prior written agreement.
Ce document est la propriété exclusive de WAVECOM. Il ne peut être communiqué ou divulgué à des tiers sans son autorisation préalable
GR64 Integrators’ Manual
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