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ARobb73
12-14-2016, 09:58 AM
Hi all!
I'm planning and buying parts for my first color mixing saber. I'm taking the leap and going with a CF8 and Xtender board.
My first saber was a NB v3, with a Gn/Rb/Rb setup to run all 3 die at the same time, when I was done with all the calculations I didn't really need any resistors because i was using a single cell setup.

Now however this 7.4 volt setup has me tilting my head a little. I understand the math to get the resistances and even the wattage of the resistors, but getting to those resistances is confusing me. I'm going with a Lime/Cyan/PC Amber custom (yeah, I like the lighter colors). The calculation for the Amber is:
(8 - 3.51) / .7 = 6.41ohm
(6.41 *(.7)^2) = 3W

So since I can't find a 6.41ohm resistor - can I solder resistors totaling 6.41 (or close too) end to end to achieve the desired resistance? I think I can, but I wouldn't mind a more experienced set of eyes giving it a glance.

Thanks!

darth_chasm
12-14-2016, 10:11 AM
Use the nominal 7.4v for your calculation and I bet you'll find a resistor in the shop that will cover your needs ;)

Edit: Actually, scratch that. You don't need resistors when using a CeX.

ARobb73
12-14-2016, 10:20 AM
Oh.
I wondered why it didn't show resistors in the CF manual - guess I just assumed I'd need them. Glad I asked. Thanks!

ARobb73
12-14-2016, 11:30 AM
So, while I'm cool with not using resistors... I'm not sure I understand why I don't need them. How does the board know not to drive my #3 die past 700 mA? Is it in the config file? (yes, I'm rtfm now trying to answer it myself but I don't recall seeing any sort of setup for that in the config portion of the manual)

Silver Serpent
12-14-2016, 12:47 PM
If you're using a CeX, then yes, the settings are in the config file.

ARobb73
12-14-2016, 02:18 PM
If you're using a CeX, then yes, the settings are in the config file.
Thanks SS, I found them & then got stuck in a meeting and couldn't post that I had until now.