User's Manual

LZT 123 1836 45

small form-factor (typically handset-sized) Li-Ion battery capacity varies

considerably, some batteries are rated as high as 3200mAh (600mAh to 1800mAH

are more commonly available)

weight is generally not a problem with typical GS64 user application, even so small

form-factor Li-Ion batteries (up to 1800mAh) can vary between 10 to 40 grams

size is generally a factor of capacity, since larger capacity batteries naturally have

more material/cells, and will range between 2750mm

to 18000mm

for small form-

factor Li-Ion batteries

the speed by which lithium-ion ages is governed by temperature and state-of-

charge; high temperatures and deep discharge will effect useful life

if possible avoid frequent full discharges because this puts additional strain on the

battery, partial discharges with frequent recharges are better

never short circuit the terminals of a Li-Ion battery

do not expose Li-Ion batteries to moisture or rain

monitor battery temperature during charging using a thermistor placed on or near the

battery wired to an ADC input on the module

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 GS64 demands (~3A pk)

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 module cut-

off point (3.2V) will provide around 95% of its total charge capacity. For a standby

(idle) current of 18mA, the module will typically provide

600*0.95/18 = 32 hours standby time