Goggle defogger

**cheese** · 5th January 2010, 13:59

So I was a bit bored at work and I saw some PDA fans that were doing sitting about and some nichrome wire which is what is used in heaters, toasters etc and remembered talking a while ago about a defogger for goggles.... so I got inventing... LOL

So the concept is simple enough, the fan is pretty small (15mm square) and only draws 30ma at 4v and the nichrome wire will draw 0.5a at 4v which gives you a 2w heater. If 2w is enough to defog goggles all well and good. I can then use some lithium button cells which are pretty cheap and small and have 230mA capacity. This would run the fan and heater for around 15 mins continuous with one fan, but I’d put two in (one each side of the goggles) so 7 mins run time. If it’s not enough, I can add another button cell and the heater will run much hotter and give about a 4-5w heater. The air flow from the fan alone might be enough to stop fogging, but I’ll have to do some tests. Pretty pointless at this time of year, but meh, I got some time on my hands. I’ll take a pic later tonight.

**scumdog** · 5th January 2010, 14:18

I wouldn't worry about the fan, hell the element heat + air currents would be enough!

But then again, would you get anything that is light and compact enough yet still work?

**cheese** · 5th January 2010, 14:49

Not sure really. Like I said I was just dicking about at work. I just ran it up and I have to use a bigger battery for the heater. I've got some 16850's at work that will run everything well enough. The bonus with that battery is that its 2500ma, so it would run for ages!

**laserracer** · 5th January 2010, 14:51

yeah i remember chatting about this ..nice one cheese....shit its getting hot at the moment

..how about air conditioned goggles....mmmmm nice cool air while you are at it how about an air conditioned helmet as well

**cave weta** · 5th January 2010, 14:58

I just piss in mine....

**cheese** · 5th January 2010, 15:10

Pissing in them is a bit smelly, I did get some rain-x stuff, but thought I'd be flashy.

Air con helmet..... doable, but probably a bit heavy! LOL

**cheese** · 5th January 2010, 15:10

Double post. Don't know how I did that!

**Blagger** · 5th January 2010, 18:45

The old roadbike trick I remember was Pledge furniture polish on the visor because it used to fill in the scratches that made night driving a bit starry.

Howabout heat elements positioned over the incoming airflow cos, if you're going fast enough, there's plenty of airflow, right?

**Daffyd** · 5th January 2010, 18:55

Try connecting the element in series with the fan. If you get the resistance right you could connect it all up to the bike battery.

(Will involve a bit of trial & error.)

**B0000M** · 5th January 2010, 19:30

the bike battery....

**cheese** · 5th January 2010, 21:04

LOL yeah I know Sam....

Anyway, I tested it and it works reasonably well! With two fans and maybe running off two CR123 batteries so its running at 8v it would work better, but not too sure It I want something at 100 degrees near my eyes. I'll set it up with tow fans and give it another crack for shits and giggles. Only other issue is that I can only fit the fans at the top of my goggles which doesn't make much sense as heat rises.....