# Thread: First time wiring up an 18650 & recharge port

1. ## First time wiring up an 18650 & recharge port

Hi, all.
I'm hoping someone can verify that I've got the right wiring schematic here.
All I'm trying to do is replace a busted AAA battery pack with 1, an 18650 and 2, a recharge port.

tcss-us-rewiring.jpg

Actually, typing out this post makes me realize: I may not have a buckpuck, I may have a resistor, so then do I need to add in a new resistor? I'm doing this on a US saber, and https://www.thecustomsabershop.com/C...LED-P1035.aspx says for the green tri-cree, it has a forward voltage @ 1000mA of 3.7V.

4x AAA -> 18650 conversion:
4 AAA in series will be 6V
18650 is 4.2V

So then consulting http://forums.thecustomsabershop.com...e-to-Ohm-s-Law :
AAA build:
R = ( 6 - 3.7 ) / 1 = 2.3 ohm
P = R * I^2 = 2.3 * 1^2 = 2.3 W, so I probably have a 2 ohm, 2 watt resistor already in there.
What I'll need is:
R = ( 4.2 - 3.7 ) / 1 = 0.5 ohm
P = 0.5 * 1^2 = 0.5 W, so I'll need to rip out my current resistor and replace it with a 0.5 ohm, 0.5 watt resistor.

So then my questions are:
1, is my wiring diagram at the top correct?
2, are my calculations correct? I have other sabers I need to repair, so I want to make sure my process is correct for (say) a 3.4V LED.
3, since the 18650 is 3.7V and the green LED is run at 3.7V, can I skip a resistor entirely, or do I still want a tiny resistor?
4, someday I want to also convert my 2x 14500s setups into using 18650s as well. My thinking is that I just have to make sure I'm buying 7.4V 18650s, and I just replace them without any other mods (I'm pretty sure my Li-ion sabers have buckpucks). Is that correct?

Thanks in advance for any help!

2. The wiring looks correct. The 2ohm resistor is larger than the 0.5ohm but I doubt if the difference is visible. its good practice to resistor all LEDS for safety/peace of mind.

Greenie.

3. Thanks for the confirmation and info! Much appreciated.

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•