tripple XPG's active cooling question
hello to all u light people.
I almost got all the parts for the bulid and only need a small advise about installing a fan.
my build is:
3 single XPG's will run in series in up to 1000mah each in.
battery is 4 cell 18650 14.8V , 2400mah
I thinks I'll need a fan to keep it cool (here in israel we ride in high humidity and about 25-30 degree C at night..
I need a small fan as possible, how much V / mah should it have and whats the best way to wire it?
p.s - will a small fan from vga adapter card (like G-force) do the job?
Small fan will do wonders, use a 7812 or 7805 depending on fan's voltage. Put a thermostat in series with input pin of 78xx. Hook directly to battery input, fan will only run when light is hot. You can get a thermostat in a TO220 case. Look up Rubix cube light. It used a nice fan set up. James
Why not build a case with enough surface area instead of resorting to a fan? The amount of surface area needed to keep 3 XPGs cool isn't large enough to really present a significant design problems given that you get a fair amount of airflow at typical mountain bike speeds. Then you avoid all the drawbacks of including a fan in the design.
- extra power consumption
- additional drive electronics
- reliability (being a electro-mechanical device, the reliability of a fan is much less than other components like LEDs)
- weather proofing - fans need to be protected from water
I tried this using a 25mm x 8mm 5v DC fan. It wasn't anywhere close to being enough air flow to make any sort of impact on a 20mm triple XP-E board.
A 3x single XP-G setup wouldn't require a ton of surface area to stay within the rec'd operating temperatures.
My "revised" double barrel design is proof of that:
Second Double Barrel Regina...revised...
The barrels barely get warm on some significantly warm nights.