Battery and/or led upgrade

[AMK]

I have a Dominix V2 with a red led but I don't like the two AAA battery solution. Can I just remove it and replace it with an 18650 holder without changing anything else? If not, while I'm in there I might swap the led to a tri red and just rewire everything. The saber is about 6 years old as of now, so I want to breathe some new life into it.

[Rapine]

Funny you should ask AMK,

A buddy and I were just discussing that.  The only problem is finding a holder to accommodate an 18650, and still fit inside the hilt.  

The V2s are 1.16" in diameter for about 2.5", then it goes down to around an inch...
  
Even a 2xAA holder is slightly longer.

And yes, if you were to change the voltage, you'd need to change the resistors as well, so you might as well do the LED.
 

[AMK]

If I do get the 18650 to fit, do you know what resistor to use with a tri-Cree R/R/R and would a tri-cree led lens fit in the ultrasabers led module?

[Rapine]

Use an online resistor calculator to determine that.  It's easy.  I do.

Here's one:  link  You'd most likely do them in parallel, the numbers will be with the actual LED star. 

And yep - 1" LED module.

[scifidude79]

Well, it's possible.



(click images to enlarge)

I actually did this earlier. I figured out an 18650 in a Keystone battery holder will fit up into the hilt, past the 1.16ch in section. I was trying to use a different holder before that I thought was smaller, but it's actually bigger. The Velcro is super glued on there, both to keep the back end from rattling around and to keep the battery from going too far into the hilt. It's tight getting it in there, but it does work. I looped a piece of spare wire around, stripped and soldered the ends together and then put some 1/8 inch heat shrink on it to make a pull to get the thing out of the saber.

[Rapine]

Excellent!

Way to jump on that SFD, and thanks.

+1

[scifidude79]

You know I've been working on it. I too dislike AAA battery setups.

[Rapine]

You know I've been working on it. I too dislike AAA battery setups.

Yep - did...you were the "buddy" I referred to.

[Infinit01]

Thanks for the write up, SFD. My Dom recently shattered it's crappy battery case this past weekend so it's down for the count. I needed this. +1

[AMK]

Should I resistor each red individually or just connect them together in parallel and use a single resistor on them?

[scifidude79]

The second one. Twist all the wires together and solder them to a single wire. Then put the resistor on that. It's your call if you put it on the positive or negative wire.

[AMK]

So the LEDs are 2.65 V @1000 mA, 2.65 V @1000 mA, and 2.5 V @1000mA. this means that the resistance of each is just 2.65, 2.65, and 2.5 respectively (their voltage divided by 1 A). Now that they're in parallel we have this equation where R is the unknown resistor value:
3.7V=3A*[(2/2.65+1/2.5)^(-1)+R]
This tells us that the needed resistor for this Tri-Cree setup is a single 0.367 ohm resistor.

I'm not great at physics, so forgive me, but can someone please double check that work for me? It doesn't seem right

[Chad mikolyski]

Hey there!

Just saw this. There are a couple things you will want to change from your current set up for safety sake and to avoid blowing the LEDs.

So the resistance value you will need is about 1ohm-1.5ohm (roughly) and you will want to wire one to each die so three 1 ohm resistors all in parralell will work okay for that set-up supposing you are using an 18650 at 3.7v.

If you use a .367ohm resistor you will be letting almost 3000mah of current to each led which would blow your leds out. Here is a great resistor tool i use:

http://www.ohmslawcalculator.com/led-resistor-calculator

The reason i recommend using one resistor for each die is because there is less chance of runaway voltage and also otherwise you will be drawing all the current through that one resistor so it could get hot from all that current. Using 3 separate in parallel is a safer way to go but not 100% required as a lot of the time it will be okay with just one depending on the Watt rating.