how many 9v batts for two 12v fans?

[DizzyStormtrooper[501st]]

I thought the answer was 3 but i'm double checking. A quick diagram in paint would help too with wiring, you bridge the negative of battery A to positive of battery B and continue the loop right?

[SCTrooper[TK]]

I would use 1 battery per fan and put an switch on each one, that way you can use one fan if needed.  2 fans are good for really warm weather.

[Tolo[TK]]

I would use 1 battery per fan and put an switch on each one, that way you can use one fan if needed. 2 fans are good for really warm weather.

That's what I'm doing and it works great.

 

 

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[Echo[TK]]

Every test I've tried with 9v's end up with a very short lifespan. 1hr maybe 2. 4'AA's will give you about 10-12hrs for either one or two fans.

 

But if you are going to use 9v's then I agree only one per fan.

 

There have been instances where people have used 2 9v's with my dual fans and the run out of power in 10 min. In one instance one of the fans burned out entirely.

 

Now admittedly I'm an amateur when it comes to electrical issues, so if anyone with real experience has other suggestions, that would be great

[DizzyStormtrooper[501st]]

I tried the one per fan and it wasn't enough power. The battery started heating up too. They're 12v fans that were used to cool down the electronics inside police cars so they won't run on lower voltage. I'm just using them till evilboys fans come in

[gmrhodes13[Staff]]

I use small computer fans with 1 x 7.2 volt battery pack form model remote cars, last heaps longer than 2 x 9 volt batteries and keeps me cool all day

[DizzyStormtrooper[501st]]

I'll have to try it old sarge's way http://www.legionxxiv.org/starmormods/

[SCTrooper[TK]]

IMHO the duracell 9v last the longest, around 5 hours. The cheaper batteries just don't last.