12v Fan help...

[fivesmallworlds]

I have a bunch of 12v fans that I'll be incorporating into my new canopy soon. My question is, how many fans can I wire to a wall wart? 2, 6, 10?

Thanks in Advance

[hypertech]

The fans should say what their current draw is. Your wall wart should also say how much current it can supply.

Divide the two and you have your max number. Since those numbers are not always right, I'd add a margin in there and not run the full load.

[David Grigor]

It all depends on the size of your dc adapter and the fans themselves. For a questimate on 3" fans ( no experience with 4" ones ) about 1 fan per 250ma of your DC adapter size. Also check the wall plug after a day or so to make sure it isn't running too hot.

[hypertech]

I'd also suggest that you put bullet connectors or something on them so the fans are easily replaced and run them in parallel so they don't all shutdown if one fails.

[NandKBlock]

ditto. you should be able to find a mA rating for your fans and a similar rating for your adaptor. Just don't exceed the rating on the adaptor and you're golden.

[fivesmallworlds]

Thanks all!

[flyingclay]

if you have an old computer power supply you can convert it to 12v and use it for all your fans and also leds for moonlight.
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
this shows how and it works very well and has enough power to run many fans. Ive been using one for my leds and fans for about 6 months without a problem. hope this helps, Les

[NandKBlock]

I'm using an old laptop power cord. Same concept but smaller.

[Fish'InMN]

I'm using an old laptop power cord. Same concept but smaller.

Laptop power supplies usually have the added benefit of being regulated, that means a steady 12VDC no matter what the current draw is. Can't say the same for most wall warts though: I measured one at 18VDC with no load while the rating at full load (.5A) was 9VDC! When you're experimenting with LEDs that run 5 to 8 bucks per diode, that will ruin your day very quickly!

[hypertech]

Be careful with the laptop supplies - I've never had a 12V one. I think mine are always 18-20V.

[NandKBlock]

All those adaptors have to have the currents and amp listed onthem. The one I have has both a 12v supply rated for 3.5 amps and two 5v supplies rated for 1.5 amps. All I did was cut the end that connected to the laptop off and used a multimeter to figure out which wires were what volts/amps. As it turned out, yellow was 12v, reds were 5vs. The nice thing about laptop adaptors is the high amps they're rated for compared to a lot of less expensive converters.

[Pomacanthus]

TIP Some of these are horribly loud, beyond what most significant others can tolerate. I discovered that using a adjustable DC powersupply from Radio Shack you can a 12V fan at 9V and its 10X quieter than @12V.
Mileage may vary.;)

[fivesmallworlds]

Thanks Pom. The fans are a bit noisy, but they don't run very often so it doesn't really bother me.