Batteries for two 12V fans

[kalkulator]

Hello, have a simple question to ask you guys, because I dont have much experience in this field.

So I have two 12V fans (80mm) that need to be controlled remotely. I got myself a 2 channel wireless switch and two fans. The problem is that fans need to work on battery, and are quite strong, each is using about 0,5 amp and 12V. The battery will have to be as small as possible, and will have to be able to run fans for at least one hour, maybe a little less is acceptable too.
Is there anything you can recommend me?

Thanks.

 

[treez]

what type of fans are they?.....do they have a pwminput that you can use to reduce their speed so that the battery will last longer....or alternatively , you may be able to use a buck converter to reduce the voltage to the fane so that they draw less current and go slower, again making the batt last longer

 

[kalkulator]

Hey, this is the description of fans: PC Server Fan Delta AFB0812SH DC Brushless 80mm Fan 0,51A 3-pin Tachosignal.
The thing is that I need them to spin as fast as possible, that is why I am using such strong fans, maybe I could lower voltage a little if it will be absolutely necessary.

 

[BradtheRad]

each is using about 0,5 amp and 12V. The battery will have to be as small as possible, and will have to be able to run fans for at least one hour, maybe a little less is acceptable too.

AA batteries will do the job. 10 of them. You need an Amp-hour rating of 0.5 minimum per fan. You have two fans, for a total of 1 Amp-hour.

You may even get by with AAA batteries, as long as they are sufficient capacity.

I assume you'll use rechargeables. Nominally 1.2 or 1.25 V each. That is why I suggest you put 10 in series. All contact surfaces must be shiny clean. Or else purchase an assembled 12V battery pack.

 

[treez]

also, lithium batteries are very small, or can be made so, and have much charge

 

[asdf44]

AA is a good option. Note that AA's are in the 2-3aH territory so you have headroom on the capacity. If you could go down on fan voltage (and up on current) you could reduce the number of cells and still hit 1 hour.

Other options - look at the hobby industry. Remote controlled cars/planes etc have assembled packs in this ballpark of power and voltage in both NiMH and Lithium and in lots of different sizes. Lithium of course will be much smaller but comes with more headaches.

 

[treez]

there a new type of lithium battery that has come in now for power drills etc...look into that. Its something like Lithium Phosphate or lithium polymer

 

[kalkulator]

Thanks everyone for helping. I don't really need the batteries to be rechargeable, because it will be for a one time event, until then I can test it with a PSU connected to electricity. But I need the smallest option available. So I guess those small 12V batteries won't do the job? AAA pack is another option, I'll keep that in mind.

 

[kam1787]

=kalkulator;1413574]So I guess those small 12V batteries won't do the job?

https://data.energizer.com/PDFs/A23Z.pdf

As far as I am aware those small 12V batteries are more for intermittent use - a pulse, rather than more continuous use.

 

[treez]

most batteries can deliver "1C" continuously at temperatures up to 45degC ambient at least

 

[kalkulator]

Hmm, ok I see now that A23 only has about 55 mAh, which is not enough. I guess I will go with AAA pack. And there wont be any problem that fans will pull 1A, is not too much for batteries to handle and get too hot or something?