electrical question about charging..resistor values..limiting current.etc

[Clint]

each little nimh 1.2v 150mA batteries say they want to be charged at1.5v, 15mA for 16hours(online pdf specs)..instead of buying a peak charger...which i might do tomorrow anyway..ive been thinking about just slow charging the batteries manually.
will slow charging a fully dishcharged battery be similar to charging them in an r/c peak charger? ie ..will i get more runtime. i'm doing a balsa rc plane and i need all the runtime i can get from each batt.

i have a small 100mA power supply that does 3v and 4.5v, 6v, 7.5v, 9v @ 100mA

i want to slow charge a dual cell which is 2.4v and a 3 cell which is 3.6v
can i use the LED resistor principle to limit the current to 15mA..ie

can i use?
limiting resistor=(voltage of power source - voltage of battery) / desired mA)*1000

so for a 16 hour charge of a dual cell
((3v-2.4v)/15mA)*1000=40Ohm limiting resistor

for a 16 hour charge of a triple cell
((4.5v-3.6v)/15mA)*1000=60Ohm limiting resistor

for a 16 hour charge of a quad cell
((6v-4.8v)/15mA)*1000=80Ohm limiting resistor


discharging is done automatically by the bits, since u cant turn the cars off..they just drain off in an hour or two naturally. i know i'll need a switch so the charger doesnt power the board while slow charging..that would just be wasted effort.