What guage wire?
- Thread starter LED4LYF
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Mr Happy
Flashlight Enthusiast
Re: What gauge wire?
With large high power wiring (like house wiring), the gauge is about heat generation and temperature rise. With short low power wiring (like flashlights), the gauge is about resistance and voltage drops.
So what gauge wire to use depends on the length of the connections. Longer connections need thicker wire to keep the resistance down, short connects can use thinner wire. If your connections are less than one inch you can really use remarkably thin wire.
With large high power wiring (like house wiring), the gauge is about heat generation and temperature rise. With short low power wiring (like flashlights), the gauge is about resistance and voltage drops.
So what gauge wire to use depends on the length of the connections. Longer connections need thicker wire to keep the resistance down, short connects can use thinner wire. If your connections are less than one inch you can really use remarkably thin wire.
Al Combs
Enlightened
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- Jul 2, 2007
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- 872
Here's a handy table for wire size vs current. 'Chassis' is the column to use for this kind of short run. The battery current depends on what batteries you use. The higher the boost ratio, the higher the battery current. If you figure roughly 3.4 volts per LED, then a 3 cell Li-Ion pack is about right. Battery current=boost ratio*LED current*1.11. The 1.11 is for 90% driver efficiency. I figure that 6*XR-E's is roughly the same as 7*XP-G's. That's ((3.4*7)/(3.7*3))*1.11=2.38 amps. That's a minimum of 25 gauge for the battery and 29 gauge for the LED's. As far as what's available, buy some 24 gauge and you can do the whole thing with just one kind of wire. Don't forget to heat sink your Blue Shark.
mdocod
Flashaholic
Re: What gauge wire?
Good rule of thumb: Use the largest wire you can use that is practical for install within the space allotted. 1A will flow fine on just about anything though.
Good rule of thumb: Use the largest wire you can use that is practical for install within the space allotted. 1A will flow fine on just about anything though.
kuksul08
Enlightened
Re: What gauge wire?
I find 22 or 24 Ga works for most of my flashlight projects, and use 18 or 20 for longer lengths.
I find 22 or 24 Ga works for most of my flashlight projects, and use 18 or 20 for longer lengths.
Th232
Flashlight Enthusiast
Re: What gauge wire?
+1 on that. I go for the largest size I have that'll still fit through the hole on the PCB. And if I'm still iffy about it and think that the pad's large enough, I'll just ignore the hole and solder larger wire on top of the pad instead.
+1 on that. I go for the largest size I have that'll still fit through the hole on the PCB. And if I'm still iffy about it and think that the pad's large enough, I'll just ignore the hole and solder larger wire on top of the pad instead.
Last edited:
uplite
Enlightened
- Joined
- Aug 7, 2009
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- 307
Re: What gauge wire?
LED4LYF, you forgot to mention the current from the battery pack.
FYI, this table gives the max current for different gauges of copper wire:
http://www.powerstream.com/Wire_Size.htm
There's also a voltage drop calculator. Very important for long runs of wire, or narrow wires in voltage-critical applications.
-Jeff
LED4LYF, you forgot to mention the current from the battery pack.
FYI, this table gives the max current for different gauges of copper wire:
http://www.powerstream.com/Wire_Size.htm
There's also a voltage drop calculator. Very important for long runs of wire, or narrow wires in voltage-critical applications.
-Jeff
