On Sunday 06 July 2014 03:12:32 Gregg Eshelman did opine And Gene did reply: > I figure if anyone knows where to get anything electronic, it's this > group. :) > > I have a couple of thermoelectric coolers with inside and outside fans. > One's a Coleman, the other is an Igloo. They both have cheap brush type > motors that are terribly noisy. Must have a square commutator or > something. > > Igloo used to sell a brushless DC motor upgrade/replacement for theirs > but has discontinued it and every place dealing in TEC parts is sold > out. The Coleman looks like it uses the exact same motor and fans, but > I can't find even the original style motor for it. > > An alternate idea is to do a bit of hacking and replace the single > motor and dual fans with a pair of muffin fans, running the inside > wires through the motor shaft hole. 'Tis doable but on these I'd > rather retain the original type setup and I don't want a couple of 36 > quart capacity freezers. (See below.) > > Some of these TECs are apparently designed to be less than optimally > efficient. I took a small one made to hold 9 12 oz beverage cans and > 'enhanced' it a bit. > > First thing was to toss the noisy motor and squirrel cage fan. Plugged > the motor hole in the insulation with a piece of foam board and metal > tape. > > Next I opened up the air inlet slots to match the area of a 4" muffin > fan salvaged from a defekt PC power supply. > > Then I took the Peltier and heatsink off. > The surface of the heatsink against the Peltier was rough, almost like > it'd been hacked at with a chisel. So I rounded all its sharp corners > to improve airflow then bead blasted it to slightly roughen and > increase surface area, then finished it by filing the contact surface > flat. > > The coldsink on cheap TECs is a stamped aluminum tub, very thin and the > pressure of the four bolts holding the Peltier sandwich together > ensures warping and lousy contact. Careful work with a body hammer and > dolly gets that flat, then a piece of aluminum sheet with holes to > match the tub is applied as a stiffener to ensure flat contact to the > Peltier. Both sides of that stiffener get bead blasted. > > Reassemble with fresh, white, heatsink compound on both sides of the > Peltier and between the stiffener and tub. Also use caulking or make a > gasket from closed cell craft foam sheet to keep condensation away from > the Peltier. Don't use any goop that smells like vinegar! That's acetic > acid which is plenty strong enough to destroy electronic parts. > > With the drastically improved Peltier contact plus the bead blasting, > airflow restriction easing and the greater air volume of the muffin > fan... drinks get chilled pretty darn quick and it'll keep ice cream > (it's large enough to hold a half gallon, remember those, box) frozen > to just the right degree of firmness for easy scooping. > > I've done the same to a Coke mini fridge and a couple of old Koolatrons > (made back when Koolatron was the only TEC company). The Coke one > already had a muffin fan and I left the original fans (with noisy > motors) on the Koolatrons. A large factor affecting how cold these > things get seems to be how much airflow goes over the hot side. > > Just applying fresh compound, addressing any contact surface flatness > issues and de-cornering and bead blasting the hot and cold sinks > (especially if there's an internal fan) improves how well they work, > especially on old ones where the compound has dried up on the hot side.
I have one of those, fits a 6 pack of cans. Draws 10 amps & might do 20F between inside and out. Leave it plugged in overnight = dead battery. I used it on one trip to Iron Mtn MI, drank lukewarm coke & canned tea. I thru it on the shelf in the basement (our "midden heap") and haven't fooled with it since. Your telling me there is actually hope to make it work better? I didn't notice any great amount of heat coming from the hot side vents, but it seemed to me it should have worked better than it did. Now I'll have to drag it down & see if I can get into it without demolishing the plastic. Interesting Gregg, thanks. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
