View Full Version : in need of cooling assistance

08-01-2009, 07:19 AM
i am in need of a way to cool my self down while wearing my Robo (Chrono Trigger) costume.


here is my thought for this project.

I want to wire multiple computer case fans along the inside of the torso to help keep cool.

but i want to keep them all hooked up to the same switch. i also would like the power source to last for an entire cosplay session(1-2 hours each day because of heat exhaustion. if the cooling system works, i'll be able to wear it longer).

so far in my searches through the internet ive only found howto's on how to wire 1 fan to 1 battery and 1 switch.

I am unsure of how to go about wiring a system that would use... lets say 6 fans, to 1 switch.

also unsure of how much juice each fan would take.

i have an idea in my head, but it could be completely wrong and i dont want to risk catching my self on fire while wearing flammable material.

08-01-2009, 10:41 AM
The fans will have a power rating in amps on them. Batteries will have a mah rating, or milli-amp-hour. It's just basic math.

1000mah is 1amp of power at (battery voltage) for one hour.


You want to run 6 fans @ 12v for 2 hours. You'll need 12v of battery, best bang for the buck is the Heavy Duty lantern batteries (the square ones with the springs on top). If you wire a pair of those together in parallel you'll get 12v.


Now is where the math comes in. I grabbed a couple of my spare 120mm fans and they call for 0.4amp, or 400ma @12v. So, here's the math using 6 of these:

6 fans x 400ma x 2hours = 2400ma x 2hours = 4800mah = 4.8amps every hour

The Energizer and Everready lantern batteries are saying they're 2600mah, so if you wired 2 together you'd get about a half hour out of each pair. Not going to be enough for what you want probably. If you have the ability to do it, a sealed motorcycle battery might be the trick. They're already 12v, the sealed ones don't vent gas, and for about $40 you can have a battery that will last upwards of 3-4 hours in a package that weighs about 8-9lb. If you figure out what fans you want to actually use, I can do all the math for you quick & easy. 80mm fans will draw about .7amps total, so it's really about balancing your battery weight vs. airflow quantity.

As for the wiring, it'll look something similar to this:

(-BATT1+)-(-BATT2+)--(-SWITCH+)-|------(+FAN3-)-------(TO BATT)

Split the + wires from the switch out to each fan, then back from each fan to the batteries. One switch, 6 fans. If you want more exact control, you could split it into fan groups, like a switch that runs all the head/neck fans, another that runs the chest/torso fans, and a third switch to run the leg fans. That way if it's cool out you don't have to freeze just to get fresh air to breathe.

As for the setting yourself on fire, wire is rated by thickness, called AWG, by how much amperage it'll take before it breaks down. The lower the number, the more amperage it'll take. It's the amperage that does the work, the voltage is just how fast it gets there. You'll want a wire rated for more than your max draw between the batteries and the switch, but if you're splitting the wires out to each fan then each wire only has to be thick enough to power the fan it's running, not all the fans in the system. Something like this:

|thin wire(+FAN1-)--|->thin wire to batt -
|thin wire(+FAN2-)--|->thin wire to batt -
(-BATT1+)THICK(-BATT2+)THICK(-SWITCH+)-|thin wire(+FAN3-)->thin wire to batt -
|thin wire(+FAN4-)--|->thin wire to batt -
|thin wire(+FAN5-)--|->thin wire to batt -

Does all that make sense? Feel free to PM me if you'd like more details, math done, wiring diagrams, etc.

08-01-2009, 02:58 PM
1st: Go out and buy Under Armor! Under Armor comes in a variety of colors

an alternative method. Go out and purchase a few gel packs, just like you put into a cooler. Sew a harness to put them near your torso. I would suggest getting twice the number of packs you will need, so you can have replacements sitting either in a cooler on ice or in a freezer.

If you are looking at using 12v computer fans. I have 5 smaller ones mounted inside my master chief helmet. (4 mini fans, 1-2" fan in the chin) I went overkill since I occasionally wear it outside and will be wearing it in a couple of parades. I power them by 2 - rechargable Lithium 9v batteries in parallel.

Your main overheat spots on your body are your head and your chest/upper back just below your neck.

08-02-2009, 03:08 AM
im hoping to get as much weight off as possible, the entire costume already weighs about 80 lbs as it is.

are you talking about those lantern batteries you find in the camping section? the ones the size/weight of a brick?

I would prefer to use something a little lighter than that.

there also isnt a whole lot of room inside that thing for large batter packs.

Sirblood, how long do your fans last powered by the 9v batteries?

08-02-2009, 10:00 AM
bear in mind they are mini computer fans.

I can run my 4 blue high intensity automotive LED's and 3 cooling fans for most of the day.

I have 2 larger cooling fans like you are talking about in the backpack part of my costume, if I run both of them I can get like 2 or 3 hours tops off of a fresh pair of 9v batteries. I usually put the helmet batteries that I have used off and on for the day in the backpack to finish them off, and only run 1 of the backpack fans.

Just about to buy either 6 or 8 rechargable lithium 9v batteries and start using them. They might not be cheap, but they are reusable! 4 fresh 9v batteries (decent ones) run 12-14$ The lithium ones cost like 15$ each, compare them to wearing the costume 4 times and I break even! (give or take the recharging station that can dock 4 of them at a time)

The best thing I have ever found for cooling you down though is underarmor. Its not exactly cheap, but its VERY effective! The 2nd best thing is those gel packs I mentioned. The fans are a tie for 2nd though as the helmet fans work wonders! The backpack fans are only noticable when I am outside and its hot, they are a backup cooling system I devised as I have walked in a couple of parades before.

08-03-2009, 03:26 AM
good to know.

thanks for the info.

I'll look into the underarmor for the next time i wear the costume.

the original version of my robo suit was made out of sculpted spray insulation foam. "Great stuff" covered in latex putty(the stuff used to fill cracks in basement walls). as im sure you can imagine, the costume got extremely hot. any body heat i produced was absorbed by the foam, and sent right back into my body.

over the course of the con that i wear this at, i loose about 5-7 pounds, and this is almost all from wearing this costume.

i once took the temp of the inside of the torso after wearing it for about 2 hours, 92F.

i think just getting some cooler air inside will do wonders.

08-03-2009, 08:07 PM
If you don't mind spending the money, you can also look in these: http://www.coolshirt.net/port-a-cool.html

I'm very much considering buying one for my Snowtrooper costume

08-03-2009, 10:00 PM
from the look of the front, there's a lot of slits you could carve into a vent! Trick is to take fiberglass screening. You want the black stuff, not the silver or white. You want the stuff with the smallest holes possible as those will allow less light through.

Cut the holes where the vents are, apply the fiberglass screening inside the vents and if you wanted to, a fan to blow air out of the vents. You could try blowing air in, but that's up to you. Blowing air in would get cool air inside the costume, but blowing air out would help to vent some of the built up heat.