Yaesu 2900 cooling fan set up

[KG6YSF]

I have purchased a 2900 to put in my Jeep figuring that the 75w high power setting could be good for some of my back country adventures where cell phones don't work. I have been told that the radio gets hot on high power and so I decided to put a computer cooling fan on it and wire a toggle switch with an LED to show when it's on. Now wiring the fan to work independently of the radio is what I was thinking. So I mentioned it to a friend at last nights club meeting and he said to be careful of how I wired it as to not burn out the switch or LED if the fan draws more power that one of the other items.
My thought was to run the red wire of the fan to the battery the black wire to one pole of the switch, then run the black wire of the LED to the other pole on the switch, then the other wire of the LED to the negative side of the battery. It is a simple circuit is there a problem that I don't get?
Thanks for the input.

73s

[KB5ZSM]

first off, are you using an LED with a resistor in series to limit the current through the LED? The LED w/series resistor need to be connected in parallel with the fan across the red and black wires so that when you turn the switch 'ON' it will supply power to both. Now run the black wire to ground on the jeep. Put your switch on the red wire and run the other switch lead to a 12 volt source.
P.S.   Besure to connect the LED with the anode to positive.

[N4NYY]

I have purchased a 2900 to put in my Jeep figuring that the 75w high power setting could be good for some of my back country adventures where cell phones don't work. I have been told that the radio gets hot on high power and so I decided to put a computer cooling fan on it and wire a toggle switch with an LED to show when it's on. Now wiring the fan to work independently of the radio is what I was thinking. So I mentioned it to a friend at last nights club meeting and he said to be careful of how I wired it as to not burn out the switch or LED if the fan draws more power that one of the other items.
My thought was to run the red wire of the fan to the battery the black wire to one pole of the switch, then run the black wire of the LED to the other pole on the switch, then the other wire of the LED to the negative side of the battery. It is a simple circuit is there a problem that I don't get?
Thanks for the input.

73s

Forget the toggle switch. There are likely mods on the internet using a sensor to automatically turn on the fan at a certain temp. SOme radios already come with that setup. Then you do not have to worry about turning it on and off.

[KG6YSF]

first off, are you using an LED with a resistor in series to limit the current through the LED? The LED w/series resistor need to be connected in parallel with the fan across the red and black wires so that when you turn the switch 'ON' it will supply power to both.

Yes the LED has a resistor built into the unit with positive and negative leads in place. A few Radio Shack locations still have electrical components if you can believe that. I got the fan, micro toggle, project box and LED all there. I hope they are satisfactory for the purpose.

[AD6KA]

Next time don't buy these components at Radio Shack.
Yes, they are very convenient but you can save a lot
of money shopping around.

Radio Shack charges $20.99 for a 4" 12vdc fan.
At All Electronics you can get a 12vdc 120mm fan (4.7")
for $4.25. And the metal fan guard you will need so you
don't whack your fingers is $1.60. (Not available at RS).
http://www.allelectronics.com/index.php?page=seek&id%5Bm%5D=pattern&id%5Bq%5D=120mm+fan&x=0&y=0
They also carry LED's, switches, project boxes, and
all sorts of components and spiffy stuff. At least get on
their catalog mailing list as their inventory changes.
If you plan to build more projects, you will always find
something you need at a great price at All Electronics.

I have purchased a 2900 to put in my Jeep figuring that the 75w high power setting could be good for some of my back country adventures where cell phones don't work.

So are you going to mount it under the dash in your Jeep?
With the fan blowing from the bottom up?
Some of these 2m rigs have a downward firing speaker,
I don't know how the fan would effect the sound.
you can always get an inexpensive small MFJ Extension Speaker.
They are about $13.99 and actually aren't bad.

Good luck with your installation!
73, Ken AD6KA

[KG6YSF]

Hey thanks for the link I am going to take the fan back and order one from there. The LED and switch are mounted in the box so there are bought. I am fabbing up an overhead mounting rack for the 2m, external speaker and the CB, most of the others in the Jeep club aren't hams so I still have to maintain a CB. There are a few that don't have CB so we also carry FRS, I always feel like a mobile emcoms unit. The fan will actually stick up through the top of the rack so fingers shouldn't be a problem though I'm sure one of the boys will figure out how to get the fingers bit non the less.
This is a link to a photo that is very similar to what I am thinking of.
http://www.jeepforum.com/forum/attachments/f12/554857d1359657342-overhead-cb-radio-mount-2.jpg
http://www.venemousduckracing.com/images/Jeep/100_3812.jpg
http://i235.photobucket.com/albums/ee138/sw_photo_gus/radiomount005.jpg

[WA3SKN]

The FT2900 is designed to work in a 140 degree(F) environment without a fan.  Thats higher than most radios.  If you want to add one, go ahead... but use a thermal sensor to turn it on.
73s.

-Mike.

[KG6YSF]

Well I read what Yaesu says about the unit, I also read about 150 user reviews on it and several stated that if you run high power for very long and or have long QSOs it can get hot enough to shut down due to the over heat protection built into the unit and it has gotten hot enough to cause a few, not many, but a few slight heat related burns. I am planning to use it in the back country. So high power is more than likely to get used and a couple hundred dollars is a fair amount for my budget. I am willing to spend a few dollars to protect it. 

[KE7EYX]

$200 radio
$20 add on fan project

Running full power in summer heat and NOT cooking it

~~~~PRICELESS~~~~~

[KG6YSF]

$200 radio
$20 add on fan project

Running full power in summer heat and NOT cooking it

~~~~PRICELESS~~~~~

That's exactly what I'm talkin about! We hit the 110 to 115 all summer long. It is miserable and could easily be a problem for heat sensitive items. The club even sets fans up on field day to blow across the table with the radios. Not for the operators either.

When I'm crawling a trail at 3 to 5 mph there isn't enough air movement to cool it so thats where the fan comes in. I even had to set an electric fan up for the Jeep engine that I can over ride the sensor and have it turn on constantly with a switch.

Some day I will be in Montana instead of California and I won't have to worry about the summer pressure cooker.