1. What makes a flashlight bright and light up the woods at night... the type of bulb (Incandescent vs. LED), the quantities of bulbs (1 LED vs. 6 LEDs), the type of battery (AAA vs AA vs C etc) or the number of batteries?
there are 2 ways to measure brightness, total brightness and brightness in the forward direction.
Total brightness is like a household bulb throwing light in all directions at least half is wasted going behind you.
Brightness in one direction is like a laser pointer. All the light goes in one direction very far but the beam is so narrow it is useless except as a pointer.
So you will need to decide if you need a wider beam or you need a beam that throws far.
Take a look at the pictures here:
http://www.candlepowerforums.com/vb...2-shipped...&p=3676360&viewfull=1#post3676360
The top light has a floody beam. Notice how much brighter the flowerpot on the left side is lit.
The other 2 have a much more throwy beam. The center of the beam is much brighter and will reach out farther but you may have to keep swinging the torch from side to side to see everything.
1. What makes a flashlight bright and light up the woods at night... the type of bulb (Incandescent vs. LED), the quantities of bulbs (1 LED vs. 6 LEDs), the type of battery (AAA vs AA vs C etc) or the number of batteries?
The incan bulbs that come with 2D plastic lights are not that bright. The incan bulbs that come with 15 million candlepower spotlights are brighter than the bulk of LED flashlights. LED flashlights range from 2 lumen to 1500 lumen for most production torches. So for LED vs incan it depends on the exact torches compared.
1. What makes a flashlight bright and light up the woods at night... the type of bulb (Incandescent vs. LED), the quantities of bulbs (1 LED vs. 6 LEDs), the type of battery (AAA vs AA vs C etc) or the number of batteries?
LEDs vary fro 3 lumens to 900 lumens (to 2300 for the SST-90) driven to the max. Usually multiple LED bulbs mean use of crappy out of date dim LEDs. A 9 LED 3AAA torch available cheaply everywhere is estimated to top out at 27 lumens. A 1AA Zebralight or Xeno E03 XML with a single LED can produce 200 lumens on high. But the tiny reflectors of the 1AA lights also mean they tend to be floody.
1. What makes a flashlight bright and light up the woods at night... the type of bulb (Incandescent vs. LED), the quantities of bulbs (1 LED vs. 6 LEDs), the type of battery (AAA vs AA vs C etc) or the number of batteries?
LEDs need ~3.6V to operate properly
So 1AA and 2AA (and the 2D MagLED) have to use a boost circuit to produce the voltage needed. Boost circuits tend not to drive the LED to the maximum so these lights are often dimmer than 3 cell and 4 cell with the same LED.
CR123A are 3V and is 2/3 the length of an AA. Same voltage and 1/3 the length of 2AA. So they were quite popular for a while when there is need for a bright pocket light.
You will find many people here use lithium batteries such as PCR123A & 18650 here. That is because a 18650 runs from 4.2 to 3.6V and can power up an LED all on its own. But you will have to learn safe lithium handling before using them.
1AA usually 90 lumen max though some goes as high as 200.
2AA & CR123A usually 150 lumen max.
RCR123A usually 200 lumen max.
18650 350-700 lumen max.
2*19650 or 26650 2000 lumen max.
2. Would more batteries in use at one time make the light last longer? That is, would a light with 6 AA batteries last longer than one with 3 AAs if all else is the same?
More batteries are used to provide more power. Bigger batteries produce more runtime.
LEDs need ~3.6V to operate properly.
So 1AA and 2AA (and the 2D MagLED) have to use a boost circuit to produce the voltage needed. The boost circuits use up a lot of energy shortening battery life.
The 3D MagLED does not need a boost circuit and its runtime is more than 3/2 the 2D MagLED.
More batteries produce more voltage than an LED can handle. Some Dorcy 4AA LED use a dropping resister which wastes the extra voltage as heat. Dorcy uses 4AA because 3AA alkaline goes from 4.5V to 2.7V and with the LEDs needing ~3.6V the torch goes dim when the batteries are still half full. 4AA goes from 6V to 3.6V so is a much better fit.
More batteries than 4 does not help.
EDIT
The size of reflector determines how well the torch focus.
Both these torches is 180 lumens. The Quark MiNi AA2 on the left is actually a little brighter when doing a ceiling bounce.
But point them at something. Notice the difference the bigger reflector makes?
An example for a floody light get the Quark AA² Tactical, For more concentrated beam the Quark AA² Turbo with its bigger reflector.