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Theoretical Helmet Fans Question


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Hello everyone. 

 

Before I get to the question, or possible few questions, I'll put out there what I have currently in my bucket.

 

I have 2 5v fans that are hooked up to a 5v USB battery (the Anker Astro E1 5200mAh Portable Charger), no off switch (plug in to turn on and unplug to turn off). It does well at troops, lasts for a long time (I think 10 hours or so). I am going to add toggle switches later on, but it serves me now. And it moves a lot of air in the helmet! The problem I'm now battling is I just got ukswrath's Hovi Mic Tips plus amp in my helmet, and the microphone is placed in front of my mouth. With the amp and fans on, you can hear the fans on through the microphone. Bummer. I also have his Hearing Assist System, but I don't think there will be a problem with it.

 

Now, for the theoretical question(s): Would it be possible to get 12v fans and hook them up to the USB battery and not suffer any consequences? My thinking is that using 12v fans with a 5v battery will produce enough air to keep my lenses clear and not make as much noise. However, I'm worried about battery overheating. Or another anonymous problem that may come up. I just don't want to be trooping and have the battery explode in my helmet and have a medical emergency. 

 

OR is there a way to put in a 3 way switch that can be configured like this  "Full Power -- Off -- Half Power"? Would a resistor or something need to be used for this type of configuration? How could this be done?

 

Think of a switch that has 3 steps on it, center position is off, left position is half power, and right position is full power.

 

Any advice would be helpful!

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12v fans run at 5v will do 1 of 2 things: run slower, not run at all.  It depends if they can start at low voltage.  In PCs you can get PWM controllers that just pulse the 12v on off or voltage control so it is possible.

 

And you could build a fairly basic potential divider circuit to add variable fan speed, either using resistors on a switch or with a pot.  Just a case of working out appropriate resitor values.

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You can have a 3 way toggle with one of these integrated on one side to reduce the voltage (they are adjustable)...

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That way you can have off in the middle then full power one way half power the other...

 

the force? oh I'll use the force, bring me a hammer...

Edited by gmrhodes13
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I tried 5v supply with 12v fans, after the seller sent me the wrong fans. Nothing. It didn't even make the fan twitch!<br><br>

They work ok with a 9v supply.

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Chris - That's what I was afraid of. Either that or battery overheating for some nonsensical reason. A speed control device is a great idea though. I've already been scouring eBay for computer fan controllers (why didn't I think of it before?).

 

Kev - That gizmo looks great! If the computer fan controller idea doesn't work, I could try that.

 

Mark - Good to know. I don't want to give up on my rechargeable battery yet, so no 9v's.

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Chris - That's what I was afraid of. Either that or battery overheating for some nonsensical reason. A speed control device is a great idea though. I've already been scouring eBay for computer fan controllers (why didn't I think of it before?).

 

Kev - That gizmo looks great! If the computer fan controller idea doesn't work, I could try that.

 

Mark - Good to know. I don't want to give up on my rechargeable battery yet, so no 9v's.

I've ordered some 5V fans to use with a USB battery so will let you know how I get on. Though that are standard PC style rather than blower as that's all I could get domestically with out a multi week wait. I need to work out how I'm goig to mount them yet though.
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On 5/6/2016 at 9:49 PM, themaninthesuitcase said:

I've ordered some 5V fans to use with a USB battery so will let you know how I get on. Though that are standard PC style rather than blower as that's all I could get domestically with out a multi week wait. I need to work out how I'm goig to mount them yet though.

I got these, Lil bit wide but work fine (well not installed in a bucket yet, till I collect it tomorrow!)

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the force? oh I'll use the force, bring me a hammer...

Edited by gmrhodes13
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On 5/7/2016 at 1:52 AM, AWOL said:

I got these, Lil bit wide but work fine (well not installed in a bucket yet, till I collect it tomorrow!)

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the force? oh I'll use the force, bring me a hammer...

those look perfect. I tried to find those in the uk and failed miserably!

Edited by gmrhodes13
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those look perfect. I tried to find those in the uk and failed miserably!

Well they're in the UK and in stock do treat yourself to an upgrade lol...

 

the force? oh I'll use the force, bring me a hammer...

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Thanks for the link Kev those fans are 10mm ×10mm smaller than the ones I have at the moment :smiley-sw013:

You too are welcome lol...

 

the force? oh I'll use the force, bring me a hammer...

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OK after spending 3 hrs outside today in my armour I now retract my statement of fans aren't needed I was sweating likens pig... lenses never misted but it was just got...

Glad I already have 4 of them, taking my bucket in the truck with me this week and will install them...

 

the force? oh I'll use the force, bring me a hammer...

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