Overdrive without LED driver?

[krog7d7]

Hi Guys,

I know this might seem lame....but if I'm gonna learn, I gotta ask.

I've been making simple PVC/LED sabers for about a year for friends/family.

Just the typical Lux 3 with 2 AA batteries, no resistors needed.

Is it possible to overdrive these LED's without a driver?

Like, what if I ran 4 AA batteries....4 AAA batteries.....etc, would I just fry the LED?

Thanks for helping me learn.

[FenderBender]

Yup, fry them you will.

For greens, blues, whites. Use a 3aaa 4.5v pack.

[ARKM]

If you don't have a 3AAA battery pack, you can use a 4AAA battery pack and make a dummy battery using wood dowel and aluminum foil to complete the connection.

MacGuyverism #1138.

[krog7d7]

Thank you sirs!

[Novastar]

krog... some other things to keep in mind (so you don't have to constantly re-visit this concept)... specification sheets of particular LEDs will tell you the min/nominal/max voltage... and current needs of that LED.

This gets a little tricky for newcomers to battery cells, current and so forth because (for some reason) people confuse "mAh" with "mA".

In the case of AAA alkaline cells... the little guys are rarely capable of outputting more than 1A, and definitely NOT 1.5A. Guaranteed, especially if they are directly connected to an LED.

NOTE: This does NOT reflect the "mAh" rating of a cell!! As I said above "mAh" is NOT = "mA". Just like "miles" are NOT = "miles per hour". One is a measurement... one is a measurement over time.

Anyhow... once you start using AA alkalines, it gets more tricky, since THESE can be quite capable of outputting 1A, even >1A.

Now... just what the HECK am I talking about?!?!? All this blithering about AAA cells and mA and mAh... well:

* AAA alkaline cells can naturally produce many voltages depending on how you set them up (1.5v, 3v, 4.5v, 6v)... but they are unlikely to deliver >1000mA (1A)...

* Luxeon III reds and red-Os and ambers are "brightest" @ around 1400mA or even 1500mA. And their forward voltage is 3v... but 3.3v or even > may be needed to spit out around such high current.

So... in general, it's important to understand what the heck the cells you are using are capable of delivering. Also in general... AAA cells would not be the best way (in my opinion) to drive most any saber. They are too weak.

It's a little along the lines of why a 9v "rectangular" alk cell is pretty darn useless in driving high-current LEDs. For the record, they are simply 6 AAAA (yes, that's right QUAD "A") cells, and they are quite pathetic for delivering high current. Sure, you get 9v... but with... like... what? 200mA? I don't really know--but it's not a CHANCE near 1A, let alone 1.5A.

Not to mention, it's important with the reverse thinking: like Fender said... deliver TOO much current/voltage to the LED, and you're going to kill it. Not good either. :)

[Kant Lavar]

If you don't have a 3AAA battery pack, you can use a 4AAA battery pack and make a dummy battery using wood dowel and aluminum foil to complete the connection.

MacGuyverism #1138.

I see what you did there... :cool: