# Thread: Using a 12V fan with a 9V battery...

1. ## Using a 12V fan with a 9V battery...

What would happen if I hooked up one of my computer fans (which runs on 12V DC) to a 9V battery? Would it just run slower because of less voltage? I want to know because I've got an idea but I don't want to take apart one of my fans only to find out that it won't work

2. that will work, it will run at 9v, but the battery might not last long depending how many watts the fan pulls

max

3. yeah 9 volt batterys don't last long maybe like 10min-15min if you are lucky which even 10min is pushing it

4. I remeber I ran a 12v fan (used 1.8 watts), after about 3 seconds of running it, the voltage from the battery had dropped about .25 This was a "Super Heavy Duty" better (non-alkaline) but I couldn't find an alkaline battery that would let this thing spin-up.

5. Would it last longer if I used 6 AA (1.5V) batteries? The fan is rated at 4.2 watts.

6. Either way, you dont wanna change your bats every hour. That's why batterys wont work

7. he is talking about a small test.
4.2 watts has gotta be a beast fan, maybe connect a few 9V fans in a series as a paraless circuit (as to increase amperage, not voltage) to do it.

8. 9v batteries are only 7.25 volts max ordinarily =P

9. Originally posted by Barn_Angel
he is talking about a small test.
4.2 watts has gotta be a beast fan, maybe connect a few 9V fans in a series as a paraless circuit (as to increase amperage, not voltage) to do it.
Series = Increase Volts.
Parallel = Increase Amps.

10. Originally posted by pwnt by pat
9v batteries are only 7.25 volts max ordinarily =P
wtf are you saying?

They don't rate them at 9v for nothing.

7.25 if discharged or under heavy load, maybe.

11. ## How long it will last?

I just hooked my 12v security camera to a 9v battery for power and i got a hour and 4mins of use.This was a Sunbeam dollar store battery.Just imagine a Duracell or energizer.

12. Willp, the amount of current draw for the camera is a LOT less than the fan will pull.

4.2 watts is .26 amps, yep not a weak fan.

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