Hi
Pinkfreud is right, of course, (as usual)
and it also depends on how often the flashlight is used :-),
but there is a simple equation which will take these
factors into account and gives you a straight answer:
On many bateries your find data like :1600 mAh 1.2 V
The first number is the'capacity' or charge
C = 1600 mAh = 1.6 Ah = 1.6 AmperHours
Equation is:
Time to discharge = C/ current
Current depends on bulb you use, typical it is 160mA (for .5 W bulb)
for conventional bulb, about 10 times less for new 'diode type' bulbs.
In practical terms, most brands will last about the same, namely one day,
when left on, despites the ads saying that 'XY brand' 'lasts longer'.
The differences are found between different types( Ni-Cad, Lithium ..)
You can find capacity (=charge) of different types of batteries
in references given here :
http://answers.google.com/answers/threadview?id=558992
Hedgie |
