DonJoy cool suit system!

[GlennCMC70]

the wife picked up a DonyJoy Iceman cooler for $5 today. i plan on making a cool suit set-up for it (for enduro stuff only). anyone know off the top of thier heads what resistance wil knock 12v down to 7.5v?
also looking for a shirt. let me know if you guys have one for sale. i;m normally an XL, but from what i'm told, i'll need a L cool suit shirt.

[Fbody383]

anyone know off the top of thier heads what resistance wil knock 12v down to 7.5v?


Google voltage divider then reconsider the method.

Find a 12v to 7.5 volt convertor that will handle the power, i.e. continuos wattage, you need. You could check with the mfg and see how long it will run on 12v.

This edit may not show up since the original post was invisible.

David Francis
Bachelor of Science - Electrical Engineering, 1990

[GlennCMC70]

i googled Ohms Law since i no longer have this type stuff memorized.
short story, i need a 4 ohm 12watt resistor to drop the 12v to 7.5 volt.
so fudge factor no, 5 ohm, 20 watt will be plenty to account for the 12-14 volts you can see from the alternator.

[Al Fernandez]

Are you assuming how many amps the pump draws or do you have specs or measurements? As for resistor size, I think its time you took a peek at the 21st century...
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=296-13997-5-ND

[GlennCMC70]

there are two knowns. the voltage requirement on the pump, and the amp draw on the pump. w/ that info, i can find the changes in resistance needed to knock the voltage down. since the amp draw stays the same (constant) the resistor only needs to be able to disipate the energy (heat) of the current drawn by the pump. now, if i ran the pump off 12 volts, the amp draw would be greater.

right?

[jeffburch]

Naa, as voltage supplied goes up, current draw goes down. Same total wattage.
P=IE
I have the dc to dc converters here.
MW292.
http://www.oep.co.uk/InlinePluginDCDCConverter-pageprodDet-ID122.aspx
Just like the one I gave Boudy that worked successfully on his DJ.
I'll bring you one like I said.
End of problem.
jb

[marshall_mosty]

Glenn,

http://www.powerstream.com/dc6.htm

My Donjoy system worked like a champ. The CoolShirt plugs right in without any issues. I use a toggle to cycle on/off during the race as the cooler is a bit small.

[Adam Ginsberg]

It's been about ~2 years, but a friend built a vdc reducer for my DIY DonJoy coolsuit.

Marshall is correct on both counts - the tank is a bit small, and the CoolSuit shirt plugs right in.

From experience, install the quick-disconnect units CoolSuit makes - they are FIA rated, and required in F1 cars. In an emergency, you don't have to think about disconnecting them - 17lbs of force, and they'll disconnect from one another.