Help understanding 12v 0.09amp Fans etc. - RC-Monster Forums

Gee · **Help understanding 12v 0.09amp Fans etc. -** 10.25.2007, 07:51 PM

I don't know why my brain has a problem with the relation of volts amps etc. If anyone could link me to a good place that might help me understand it better or help me relate it to RC applications. I would appreciate it. The current reason I am asking is htat I have some fans that I would like to put on my RC to help keep the ESC motors cooler. The ones I have laying in from of me are most likely from computers. They are all 12v with the amp rating as 0.19, 0.58, 0.16, and 0.09. I would guess the higher the amp the more it will draw from the batteries. Are any of these compatable for use with RC applications running 7.2v RC's. Will they require too much from the battery to be of any use? If it indicates 12v can it be connected through the receiver. I've tested them directly on a 7.2v battery and they work. This post seem a bit scattered. Hope somebody understands what I'm not sure I am asking.

phildogg · 10.25.2007, 08:26 PM

yeah 12v fans work fine .I use them,but I'm not sure the 5v from the receiver would be enough.. also the .09 amp draw would not be noticable.
phil

BrianG · 10.25.2007, 08:35 PM

Well, disregarding my dislike for relying on the use of fans, those 12v fans might run a tad slow on the receiver voltage of 5 or 6v. If you are running 2s lipo (or 6 cells), they should work, but have less output than they would at the full 12v. A 12v fan might not be able to start turning with a low voltage like 5 or 6v, so running them straight to your 7.2v battery pack would be recommended.

There are 5v fans around, but they are harder to find, but can be run straight from your receiver provided you only use one or two.

Yes, the higher the amp rating, the more it will pull from the batteries, but those numbers are all less than 1A, so any decrease in runtime will be negligible. However, if you run those at less voltage, the current draw will be less as well.

nativepaul · 08:54 PM

you could use the .58Amp one direct of 7.2 like you tried, it will draw .58Ax7.2V/12V=.348Amps, that would take 4.2AH/.348A=12hours to flatten a 4200mah pack you would be hard pushed to notice a difference in runtime, if you get 10min runs at the moment that's 4.2AHx60=252AmpMinutes /10Minutes=25.2Amps average, add .348A for the fan and it would go down to 25.2A+.348A=25.548A, 252AmpMinutes/25.548A=9.86 Minutes.

EDIT: everyone else beat me to it while I was doing the maths, but hopefully the equasions will be of some help to you working out amp draws or runtimes in the future.

Gee · 10.25.2007, 08:54 PM

THanks. That makes sense they would run slower on less voltage then 12v. So with that kind of amps it will not be noticable. I did order a couple of 5v from this link the otherday. It's nice to have the added security of a fan. I try to do it all by gearing. Had an extra novak fan and put it on my mamba esc and it was just nice to check the temp and it barely over 100.

http://http://buyextras.com/30mmdc5vfans.html