battery life

[djbordie]

I have searched high and low for this question with no luck...

with a basic electronics package from tcss, how long would the led last?
that is

red luxeon 3 star with resistor and 4-AAA batteries?

im just wondering if its at all worth it, or do i just setup my 7.2v recharchables asap.

[Novastar]

Battery life depends on several things, some of which are:

* Mah of the batteries (milliamp hours--this is usually posted after the voltage on a battery, but not always, such as "3.6v 2400Mah")

* How much your resistor is... uh... "resisting"... if the resistor is heating up, it's burning a lot of the battery energy in order to prevent the LED from being over-driven. In general, you want a battery setup with a very close forward voltage that an LED requires. For example, a 3.6v Li-Ion cell is great for lighting up a Luxeon III with a 3.4 forward voltage rating.

* Whether you use a "driver" board or not. In your case, you are saying a resistor, so there is nothing going on to regulate/manage the battery life.

That's about all I can think of right now.

[djbordie]

yeap but back to my point,

red luxeon 3 star with resistor and 4-AAA batteries? (regular duracel batts, not nimh)

so as i said, do i go and hook up my 7.2v 1600mah nimh, or will the 4 AAA duracels be good enough for now?

also approx time on the bat/resistor setup...

seeing as this is the basic electronics package from tcss, they should probably make a note of average time the saber will last for the newbs that are just going to try it with the basic package.

if its not worth my time, then i will f*&^ the basic package and then just go buy the proper resistor for my 7.2v 1600mah nimh, or possibly a driver that supports 7.2v

[Ryma Mara]

To make that 7.2V pack to work and not fry your led in a seccond you need a 3.3 Ohm 10 Watt resister. I have a feeling battery life isent gonna be to great as alot of gonna get bled of as heat.

[djbordie]

i see, so is the 4 AAA gonna be better?
or how do i save the bleed off?

[vortextwist]

an driver or a buck puck. I get pretty good run times with my AAA pack and mr board. I use rechargables and I have an couple extra sets.

[UltraSWG]

To actually answer your question, with a resistored setup on 4x AAA batteries at 1000mah, you'll get about a 45min- 1hour run time before you notice a significant drop in brightness with a red Luxeon III.

For a red Lux III, you'll actually do better running a 2x AA setup with no resistor. Battery life will more than double, and you'll be using half as many batteries.

I wouldn't reccomend the 7.2v nihm for a red Lux III unless you use a driver circuit. It will work great with a Lux V, tho.

[djbordie]

interesting, so i can actually not worry about the resistor with a 2AA setup?
does this not endanger the led? or is it the perfect voltage/mah for the led?

[UltraSWG]

The red Lux III will do great on a 3 volt direct drive setup since the normal forward voltage is 2.95 volts.

[Novastar]

Exactly... as I told djbordie in the beginning... it DEPENDS on whether you're using a driver (puck, Corbin's, Ultra's, Erv's, etc.), or a resistor.

When wiring "direct drive", you want to get as close to the forward voltage of the LED as possible.

For example (as Ultra mentions, Djbordie):

Lux V = 6.85 fwd v... so 7.2 is perfect
Lux III (let's say red) = 2.95 fwd v... so 3v is perfect.

However--with driver boards... you DO NOT want to give it "exactly" enough. You usually want to give it quite a bit more. Anyhow. Read the info threads.