Running 12v Fan + Lamp at 18v

revans · Sat Feb 23, 2008 10:13 pm

I am making a circuit which you can see here:

http://s272.photobucket.com/albums/jj17 ... ItRun2.jpg

The circuit uses two 9v battery in series (18v total) to power two 12v lamps (the voltmeters) which you can see here:

http://www.dse.co.nz/cgi-bin/dse.storef ... View/P8159

and one 12v pc fan (the electric motor) which you can see here:

http://www.trademe.co.nz/Computers/Comp ... 4.htm?p=14

There are two switches, one which controls one lamp and one which controls both the other lamp and the fan. I have tested the lamps and the fans at 18v and both work fine over short periods (though obviously overpowered). How long, though will I be able to run them as is safe? I probably would be running them for several minutes at a time, so will this be alright or will I have to use a 12v power source instead so I don't break them? Also, the fan says on it 0.13a and 1.56w. I know this may have been mentioned somewhere but it escapes me as to where so any help is great. Thanks

frankrede · Sat Feb 23, 2008 10:40 pm

I believe a resistor is made for that purpose, but I am not good with electronics so don't take my word for it

revans · Sat Feb 23, 2008 11:32 pm

Thanks for the answer, but its lost on me, I'm not good with electronics either.

TurboSuper · Sun Feb 24, 2008 7:39 am

Yes it should work. Just test the fan at 18V for a while, what's the worst that can happen?

I know for a fact that PC fans run perfectly well off 1 9V battery, try to see if the lamps do too.

singularity · Sun Feb 24, 2008 10:30 am

by "lamp" do you mean LEDs? if they are LEDs your going to need a resistor if you plan on using them at any voltage. well if you plan on keeping them alive at any voltage. if they are standard LEDs i suggest a resistor in the 300 - 500 ohm range, if they are high powered LEDs then could use like a 200 ohm resistor or something. a picture of the lamps and i could tell you for sure.

the 12v fan will run fine at 18v its effective lifetime might be cut down but remember they can run nonstop for several years without failure so i don't think there much to worry about other than melting it by the heat of combustion