Well I found general LCD data, on supplying power for the LED type backlight. Thanks to all those that steared me in the correct direction to complete this thread and locate this data.

LED type Backlight General Specs:

char/row voltage current
16X1 4.5vdc @ 160 ma.
16X2 4.5vdc @ 160 ma.
16X4 4.5vdc @ 240 ma.
20X4 4.5vdc @ 300 ma.

Max I = 150% rated I

Calculating the series resistor:

Series Resistor RS = (Vbat - Vf/ If
example:
RS = 12vdc - 4.5vdc / .160amp = 47 ohm (1.2 watt)

Since the LED backlight is a current hog, to avoid over heating the voltage regulator, it might be advisable to connect the backlight to the unregulated input side (i.e. 12vdc), going to the micro's voltage regulator. I assume, that's why they separated the data/control and backlight input voltage source pins.

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