[FS] (UK Pref) Large Peltier Units. - Page 1
Forum section: electronics / general

author: CM800
author_rank: Frequent Contributor
timestamp: January 30, 2014, 07:51:29 pm
content: The place were i currently have work experiance will be chucking out a large number of pelteir units.Anyone want to buy them? With 12v across them, they draw about 5A each (have not measured properly as i had fans attached at the time)each unit comes with or without heatsinks, the prices will be:£12 + £8 for a pelteir plate peice:£28 + £8 for a unit excluding backing plate:£30 + £8 for a whole unit:Buy 5 of any item and get 1 free! (contact me for postage costs)Postage is for UK, contact me for postage outside of UKMost aluminium frames of the units have bent corners, this can be fixed rather easly however.These heatsinks are high quality machined heatsinks with the fins pressed and glued in for better thermal dissapation then extruded versions.These units were used for special temperature controlled and logged fridges being sold at around £4,500. Each unit cost them around £400 to make,.the units are unused and almost all are undamaged (best ones go first as there are only around 5 damaged ones). The pelteir plates are quality made,not cheap china ones like on ebay as these products were top-of line.The unit is about 440mm long, the fan ports pictures are standard size fans like those found in computer PSUs.Pictures:All the parts in a whole unit:Fins on a heatsink:Partially dissassembled:Closeup of peltair unit:I have over 45 so buy up while they last!I prefure bank trans because there are no fees involved, however i will accept 'gifts' though paypal, but i will charge 20% more due to risk & charges (had bad experance with paypal)I Also accept postal order, cheque by mail, or cash on collection, other suggestions are welcome

author: logictom
author_rank: Unknown
timestamp: January 30, 2014, 09:04:39 pm
content: Any details on what temperature these will do?

author: CM800
author_rank: Frequent Contributor
timestamp: January 30, 2014, 09:10:48 pm
content: Well i have no real method of reading the temperature on one, however, when i powered one without a heatsink on the cold side, frost and such appeared very quickly, it is way to cold to touch after 10 seconds or so, and water drops freeze near instantly. I suspect it could go down to -40 or below with the correct setup and insulation.Note that these are 2 layer units, this means they can have a much higher Delta T across them.

author: dexters_lab
author_rank: Unknown
timestamp: January 31, 2014, 05:02:27 pm
content: if you could find a datasheet for the peltier element that would be ideal

author: CM800
author_rank: Frequent Contributor
timestamp: January 31, 2014, 05:42:41 pm
content: Quote from: dexters_lab on January 31, 2014, 05:02:27 pmhttp://www.peltiertec.net/docs/dp4350-277750-tec2_198xx6262_peltiertec_pdfI belive this is it.It has exactly the same size and dimensions, the only difference is that the unit is not sealed.It also draws very close to the same current at the specified voltages.

author: logictom
author_rank: Unknown
timestamp: February 02, 2014, 01:18:28 pm
content: Have you tried running them in reverse to generate heat? Looking for something to build a small temperature chamber.Who is the courier you have linked to for pricing? Could you provide a link so I can check where their depots are? Thanks.

author: dr.diesel
author_rank: Super Contributor
timestamp: February 02, 2014, 01:26:19 pm
content: Quote from: logictom on February 02, 2014, 01:18:28 pmAll Peltiers work by warming one side while cooling the other, no way around it. Either reverse the polarity or turn it over!

author: logictom
author_rank: Unknown
timestamp: February 02, 2014, 01:30:48 pm
content: Quote from: dr.diesel on February 02, 2014, 01:26:19 pmAre they marked up for hot and cold side purely for matching the red/black leads? Are they not more efficient ran one way rather than the other?

author: dr.diesel
author_rank: Super Contributor
timestamp: February 02, 2014, 01:33:48 pm
content: Quote from: logictom on February 02, 2014, 01:30:48 pmNo, I can't think of any reason they would be, at least not the Peltiers itself, top/bottom heatsink combos could be tailored however.

author: CM800
author_rank: Frequent Contributor
timestamp: February 02, 2014, 03:27:07 pm
content: My post company is parcel force, its a part of Royal Mail.these units should run fine in reverse.anyone else want to buy some? cause im shipping out the first lot on monday together.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 02, 2014, 04:27:47 pm
content: Quote from: dr.diesel on February 02, 2014, 01:26:19 pmIf it's a 2-stage stack they will be direction sensitive, as the second stage needs to pump out waste heat as well as pumped heat from the first stage.

author: CM800
author_rank: Frequent Contributor
timestamp: February 02, 2014, 05:03:25 pm
content: Quote from: mikeselectricstuff on February 02, 2014, 04:27:47 pmHuh, didn't know that! thanks for correcting my misinformation too

author: dr.diesel
author_rank: Super Contributor
timestamp: February 02, 2014, 05:28:23 pm
content: Quote from: mikeselectricstuff on February 02, 2014, 04:27:47 pmYes, but his parallel/series stack is "hard packaged", should be ok as it only has one set of leads.

author: CM800
author_rank: Frequent Contributor
timestamp: February 02, 2014, 05:33:15 pm
content: Postage for the £30 unit has raised as i have to get different boxes for them now, that cost more (cause they dont fit) All people who already ordered will not be charged the extra money now.

author: CM800
author_rank: Frequent Contributor
timestamp: February 02, 2014, 10:12:55 pm
content: All parcels have been packaged up and are due to ship tommorowStill got LOADS left to sell!

author: JoeD
author_rank: Contributor
timestamp: February 04, 2014, 09:06:30 pm
content: How are the Peltier units attached to the block shown in your first photograph. Do they come off easily as I have an application but it really needs the Peltier units alone without the block etc as the corresponding functionality will be custom built for my application.JoeD

author: CM800
author_rank: Frequent Contributor
timestamp: February 05, 2014, 06:58:22 am
content: I have been unable to get them off, but as half of them come off on the other part too, you can likely find some way of getting them off!

author: scientist
author_rank: Frequent Contributor
timestamp: February 05, 2014, 10:04:24 am
content: That's a lot of bismuth telluride. You could probably get more than that just for scrap.

author: CM800
author_rank: Frequent Contributor
timestamp: February 05, 2014, 08:39:21 pm
content: Mind telling me where to sell it then? XD

author: logictom
author_rank: Unknown
timestamp: February 08, 2014, 12:01:14 pm
content: I got the parcel this morning, thanks.One of the units is damaged,bit miffed as you mention only have a handful of damaged units and still have loads left to sell yet I have received a damaged unit?Update: This was damage in transit.

author: CM800
author_rank: Frequent Contributor
timestamp: February 08, 2014, 12:41:02 pm
content: Quote from: logictom on February 08, 2014, 12:01:14 pmI had sent it perfectly fine, i assume it got damaged in transit, the ones i have that are damaged are a tiny chip in the corner, nothing like that, i have only sent good ones out..I shall try talk to the transit company right now, will contact you back in PM when i have done so.

author: PlainName
author_rank: Super Contributor
timestamp: February 08, 2014, 12:58:05 pm
content: I ordered the full works and that arrived yesterday. The package was damaged in transit (see photo) but the item itself survived just fine and works as expected (pumps heat both ways, although I only ran it at 18W).Our delivery chap seemed a decent sort, so maybe these got kicked around a bit at the depot.

author: CM800
author_rank: Frequent Contributor
timestamp: February 08, 2014, 01:00:36 pm
content: Oh thats good, in the future i shall add an extra layer of packaging to ensure any items to deffinatly not get damaged.

author: trevwhite
author_rank: Frequent Contributor
timestamp: February 08, 2014, 01:15:58 pm
content: So has anyone done some temperature testing on these? Be interesting to see what range they have with respect to current and polarity. Could be useful for temperature testing circuit boards?

author: logictom
author_rank: Unknown
timestamp: February 08, 2014, 01:19:20 pm
content: Quote from: TCWilliamson on February 08, 2014, 12:41:02 pmSorry TCW, I had looked through the box before posting and found no remains of the damage but I just unravelled all the packing material and did find the missing chunk.

author: CM800
author_rank: Frequent Contributor
timestamp: February 08, 2014, 01:27:21 pm
content: Good news, the guys there will compensate, even though it is a ceramic amazingly

author: CM800
author_rank: Frequent Contributor
timestamp: February 08, 2014, 02:21:31 pm
content: I have sent the form to them. I intend to do a temperature test soon, any reccomendations on what gear i should use to do so? (budget of £18)

author: PlainName
author_rank: Super Contributor
timestamp: February 08, 2014, 02:22:08 pm
content: QuoteNot proper. Just wanted to see if it did anything, so shoved in 1.8A and checked it with a TIC. Use the proper way around it nosedived to -17C in short order, with ambient of around 21C. I reversed the polarity and turned it off when it got to about 57C. This is without a heatsink on one side.I am thinking about using one for making ice cream. Alternatively, vacuum packing food for freezing can be tricky if it's soup, so maybe this would let use flash freeze them enough to get 'em bagged and sealed. No idea why most of my solutions looking for a problem involve food

author: CM800
author_rank: Frequent Contributor
timestamp: February 08, 2014, 03:08:22 pm
content: Quote from: dunkemhigh on February 08, 2014, 02:22:08 pmPlease tell me how this goes!

author: scientist
author_rank: Frequent Contributor
timestamp: February 08, 2014, 08:13:40 pm
content: Quote from: dunkemhigh on February 08, 2014, 02:22:08 pmYou do realize that Peltiers are just heat pumps, right? One side gets burning hot while the other side gets freezing cold, and reversing voltage polarity switches which side gets hot or cold. That is, unless it's mounted in a heatsink in which case the polarity is relevant.

author: PlainName
author_rank: Super Contributor
timestamp: February 08, 2014, 11:12:35 pm
content: QuoteYes. What made you ask?I noticed the previous discussion that multi-layer peltiers might be directional, so tried it just in case.

author: CM800
author_rank: Frequent Contributor
timestamp: February 09, 2014, 05:27:38 pm
content: 4 more partial units shipped, still have over 30 units to sell... please buy up :~)

author: CM800
author_rank: Frequent Contributor
timestamp: February 12, 2014, 04:56:51 pm
content: Deal ended, still have loads to sell x.x come on!

author: CM800
author_rank: Frequent Contributor
timestamp: March 02, 2014, 05:20:00 pm
content: Sending replacement for broken unit to LogicTom tommorow.