Mini Dehumidifier Doesn't Collect Water - Can it be Fixed?

In this video I look at a dihl (DL-68W) mini dehumidifier. This was purchased from eBay by a viewer named Nick and it didn't work. Can it be fixed and how does a mini dehumidifier actually work?
If you would like to support these videos, please click here / mymatevince
Remember that this is just for entertainment and I am not an expert in these repairs. The processes in the video may not be the best way, the correct way or the safest way to fix these things. I do love fault finding and trying to fix broken things, so I hope that comes across in this 'Trying to FIX' series. Many thanks, Vince.

[@dorsetallsorts]

Hi Vince, this was sent to you by me, so I was very excited to see you work your magic on it! Thanks again for producing such interesting videos, I never miss one.

[@Mymatevince]

Thanks Nick, I really enjoyed this one FAR more than I thought I would. I was, and still am fascinated by these Peltier plates, especially the idea of them generating electricity when heated up. Thanks for sending it in, although the outcome wasn't very successful I had great fun messing with it 👍👍👍

[@taibataiba6461]

Thank you Vince for learning me Nintendo switch work

[@scottking5645]

​@Mymatevince would you be interested in taking a look at my neo geo pocket colour very strange fault with screen stays on for around 5 mins then after a while it just goes white and can't be seen unless looking at an awkward angle.. I don't believe I've ever seen you look at a neo geo pocket so thought you might enjoy this one?

[@emilyduffin-jy6sy]

I love learning

[@emilyduffin-jy6sy]

I like it

[@mickyparker3949]

I have one of these, and it's brilliant, I have had it for 8yrs, and I use it on the window shelf during the winter months, it works very well, I have to empty it 3 times a week as it shuts off when it's full. Good bit of kit. Love your vids always.

[@Jedda73]

There is one more part of this to complete your understanding Vince, which is the dew point. The dew point is the temperature at which moisture in the air condenses on surfaces such as the Peltier device's cold side. It is calculated with temperature and relative humidity. Using an online dew point calculator, for your room at 22 celcius, the relative humidity needs to be at least 35% for the dehumidifier to work with its cold plate at 6 celcius.

[@marianciotir91]

Finally someone knows about it. Your comment should be at the top.

[@Mark_C1]

Thanks, Vince. That was really interesting to see. I first came across those peltier plates when my mate wanted a dehumidifier for his bungalow and having seen our wanted me to recommend one. When he saw the prices of the proper units he pumped for a cheap one off amazon. Larger, but still I had it on here for 24 hours and had a few drips in the tank. For comparison, our unit I have on 24/7 pulls out 4 litres a day consistently. I took it apart and came to the conclusion that it’s relying on the plate cooling the moisture in the air being pulled across the plates to frost and then dripping off into the bucket when it gets laden enough with ice to melt the outer layer. I sent it back and he paid over twice the amount and has been happy ever since. The larger condenser types are a little more involved and I’ve had fun stripping our one down and re greasing motor bearings and cleaning the condenser fins when they get blocked with damp dust 😬

[@shuggyboy1]

theres peltiers in the wee fans that go on top of wood burning stoves, they generate power for the van motor because of the heat diferential between the base and heatsink. no batteries required :-) love the vids, keep them coming. all the best from scotland :-)

[@TragicMike]

We have one of these, its sits on the side table in the bedroom, its not brilliant, takes about a month to fill the resevoir and cut off to activate, but it certainly reduces condensation and mould on the windows in the winter great to see how it works though simple but very clever! Great job Vince! 👍🏼

[@J.erem.y]

Those plates are what pretty much every wine cooler uses, and those little tiny fridges that plug into the cigarette lighters in cars. They also usually have a heat-sink on the back with a computer fan to dissipate the heat. Glad you learned something.

[@ballsrgrossnugly]

Don't leave those things turned on for long periods, I found out the hard way by using one with a mains adapter as my mini-mini fridge for a single can of whatever back in the day. I left it on for maybe a month before I started to see water trickle out of the bottom of it, so I opened it up. Turns out water had pooled in the bottom and gone mouldy already due to the heat being directed out of the bottom of the unit, so there was a band of perfect breeding temperatures. Threw it out that very day.

[@ralphj4012]

Good analyses and repair. A peltier creates a differential between ambient, so yes, the cold side will be colder in a colder room, but the differential is usually fairly low in these small units. Probably not a good idea for Buckingham Palace, I expect that there is a lot of hot air (including under the collar) in there.

[@Mymatevince]

😂👍

[@ncross1857]

I've heard they wear a battery-powered version under ceremonial robes, to help with any unfortunate happenings. One can not simply nip to the bog during the State Opening of Parliament etc.

[@MayaPosch]

Peltier-based dehumidifiers generally don't work in rooms that are below 15 degrees C. They also perform terribly if humidity is

[@Mymatevince]

Thanks Maya, I thought they might be very inefficient with the heat the external power supply was producing and also the heat coming from the unit. It was acting as a small heater more than anything else 👍👍👍

[@MayaPosch]

@@Mymatevince Yeah, it's my suspicion that the very hot side in the system helps to evaporate any condensed moisture. The Seebeck effect that makes thermoelectric conductors (the TEC on those device) work is quite inefficient, so that for every unit of 'cold' you get a lot more 'hot', both from the created temperature gradient across the device and from all the wasted power that does no useful work. In comparison, a compressor-based dehumidfier works basically like your fridge, which is to say as a heat pump. Effectively, these output more power than you put in via the electrical side, as they draw away the energy released when moisture condenses. The small unit I got uses about 160 Watt (compared to ~60 Watt for the Peltier unit), yet it is infinitely better at extracting moisture from the air (jerrycans full) while also being great as a little heater. There's a third type of dehumidifier as well, which uses plates of hygroscopic material that slowly rotate, with a heating section used to recondition each plate and extract the collected moisture. Those are a bit of a toss-up with compressor-based units, but can work even in sub-zero temperatures. Hope that was a little bit informative :)

[@ddjazz]

@@MayaPosch very good info , thx maya

[@Mymatevince]

@@MayaPosch Thanks Maya 👍 I wonder if the exhaust hot air from the top of this unit was brought back around to the front again, so recircled could it be more efficient as hot air carries more moisture so would it condense more water than in its current form???? Or would the efficiency be lost because the hot air coming in would heat up the cooled Peltier heat sink. I suppose what you gain on the first cycle of recircled air you will lose on the next cycle.

[@coctailrob]

I would guess the hot air exiting would already be less humid so would be better to direct this air against a damp surface to help get that moisture out into the ambient air. The more humid the air going in the more effectively it can be extracted.

[@BuyitFixit]

Great Video Vince. Peltier elements are used in quite a few different devices. I've got a DNA PCR machine that I bought of Ebay way back and repaired that has two huge ones. They are commonly used in those cheap mini fridges you get at places like "home bargains" etc, and they are also used in those fans that you put on top of the log burner (we have one) and it uses the hot / cold differential to generate a voltage to spin the motor, instead of putting electricity into it to generate a temperature differential (yes they work both ways).

[@Mymatevince]

Thanks Mick. They are really interesting devices, shame the dehumidifier didn't do much apart from heat the room and use electricity but the Peltier plate is still cool (boom boom). I did add heat to it from my hot air station and seen the voltage increase on my multimeter but I sped it up to cut the video time down. I wonder if they could be used to produce electricity like a solar panel or combined into solar panels? I presume they are so inefficient that they couldn't be used on a hot day to produce anything meaningful?

[@BuyitFixit]

@@Mymatevince Yeah the end result on your video just seemed a bit of a wet finger! (hope your finger is doing better as it was still bandaged on the video but I'm not sure when you recorded it). I'm not sure how efficient they are, but there's enough power generated by them to keep the fan spinning above the log burner! I see you're up and commenting still at 2am lol!

[@Mymatevince]

@@BuyitFixit Fingers doing well now Mick. Yeah, bedtime any minute now😂 You might know the answer to this, if the Peltier plate was cooled as in frozen in a freezer would it produce electricity? Or is it only when heated?

[@BuyitFixit]

@@MymatevinceGlad to hear! It's not the heating or cooling it's the difference in temperature between the two sides, so if you froze it both sides would be frozen at the same time and nothing produced. I was just off to bed too. Are you finding KZbin quiet at the moment? My views seem to be down a bit 🙁

[@Mymatevince]

​@@BuyitFixit Thanks Mick, I understand now, I thought both sides would also get hot on a log burner, but I have just Googled them to see they are made from thick metal with a fin arrangement on the top to keep them cooler. It all makes sense now, thank you. KZbin seems to be the same as normal for me, it is down year on year, but no difference from Feb to March. I haven't looked at your channel since the skip find weather station. Maybe the items in the recent videos might not be as clickable. For example a games console will always get more than a dehumidifier. I'm sure another Milwaukee tool on the bench and you will be back on track. Also if you had an influx of subs from a mention or successful video etc. then they will watch your back catalogue of videos which will boost the views short term, but once they have watched the back catalogue it will revert to the normal view level, so only increasing on the days you release a video.

[@Mark-zj3xu]

I bought one of these for my daughter years ago when she went to Uni and the room was a little damp, worked perfectly and always collected water and she still has it in her rented accommodation with her partner and its still working fine. :-) I think it's more suitable for small bedsit rooms.

[@blobscott]

For liquid to condense, the cold side of the peltier needs to be at or below the "dew point" temperature for the room air you are trying to dehumidify. The dew point is based on the ambient air temperature and the room's relative humidity. I suspect the peltier would require a more powerful fan to take away enough hot-side heat in order for the cold-side to drop to the dew point for the room. Just a guess.

[@Mymatevince]

Thanks Blob 👍

[@GoGoErrek]

Peltier is ancient tech. Ineffective scrap, hence the price tag cheap but expensive to run. Better off with dehumidifying granules.

[@kriswhite9324]

@@Mymatevince Do you have a discord chat or something as I have a few items I think you might be interested in fixing possibly and great fix as always love from Australia :)

[@benjonnyshirley4203]

*For liquid to condensate

[@gerrymichaud3851]

I remember the Peltier Plate. I lived in Dallas from 1997 to 2014. I started to go to the First Saturday swap meet in 1998. It was the place to go to get computer gear. They had Peltier Plate CPU coolers at the meet. You could find great deals of motherboards, games, OS's, and find antique gadgets and cameras. It went on the last Friday night on the month to about noon on Saturday.

[@thomasebelsheiser6422]

Hey Vince. I have the same device a d I can tell you it is working. I am using it in my bathroom. After 4 Persons went under the shower you can cut the moisture of the air. With this little thing you can surely avoid having mold because it dries out the air perfectly. Carry on with your interesting videos. Greetings from Germany.

[@GadgetUK164]

Incredible coincidence lol - I have a new one of these sat on the table, and a faulty one that I've been looking at. I think the Peltier specs are key in a device like this - ie. if its too efficient (or inefficent) it doesnt work well or at all. And there does seem to be a relationship to the ambient room temperature. I've also got another larger older one I want to look back at, but my first through was to measure the temperatures on the new one. Great video Vince!!! =D

[@Mymatevince]

Thanks Chris, I'd be interested to hear the outcome of what caused the fault on your one 👍

[@jackmajor7865]

having played with these plates a bit I found that once disturbed from the heatsink, cleaning off the thermal paste and adding new made a difference to the temperature at the fins of the heatsink. Not much, but maybe enough to slightly increase the output of condensate.

[@incandescentwithrage]

Yes it pretty much does work like you said, with a maximum temperature difference between the two plates, which will always be relative to the ambient temperature. It can be found in the datasheets. They can be stacked to achieve extremely low temperatures. Peltier devices are very inefficient heat pumps, creating much more heat than cooling... which is why the hot side heatsink is always much larger. They can be used in reverse (Thermoelectric generator), as you noted, give the two sides a temperature difference and they will produce a voltage. If they were more efficient they'd see more use as heat pumps and electricity generators, but phase change refrigeration with a compressor is far ahead.

[@jb2590]

These are generally for tropical areas without central aircon. Heat pump/aircon already dehumidifies the air so we generally wont notice it where we live. You can test this by using a simple temp/humidity sensor, and you will see that we will have very little humidity.

[@SublimeArchi]

This. Also, humidity levels are generally lower in the winter as opposed to summer.

[@richardgreene3460]

I have about 17 of these dehumifiers (exactly the same, but different name brands) in my car collection! In the summer, each one will fill up the reservoir in 3 days! They work great in controlling the moisture;therefore no mold, etc. I have had 2 within 5 years that failed exactly like this one! Sadly, I tossed them! Next time, I will repair them because of Vince! PS I love your Spirit series! I have several Shadows, a Spur and Cloud in which I use the dehumidifier in the summer months (USA)!

[@DrRestoration]

Hi Vince, I made a display box for a friend who is a chocolatier. He needed the display to stay cool as he would sell chocolates at conventions and I used peltier modules to cool it. It was a very fun project, from my research the cooler the hot side the colder the cold side gets. They can be stacked to reach extreme temps, very interesting. 😊

[@Mymatevince]

Nice project! When you say stacked do you mean side by side on a large heatsink or actually stacked on top of each other, hot to cold, hot to cold etc. I'm trying to work out what would happen when stacked on top of each other, because wouldn't the cold cancel out the hot etc. and then end up the same as just having one of them. I'm so glad I found these little devices. Cheers for watching 😎

[@DrRestoration]

@@Mymatevince stacked on top of each other, however they are not very efficient. The idea is module A’s cool side against module Bs hot side would result in an even colder module B cool side, module A would need to be bigger than module B. I don’t fully understand the thermodynamics and I don’t think stacking works out in practice.

[@DrRestoration]

@@Mymatevince search peltier cascading on KZbin

[@Mymatevince]

@@DrRestoration Oh Ok, yes cheers for that. It has been said here in the comments that they generate more heat than they do cold so I suppose that is why Module A has to be bigger 👍👍👍

[@coolissimo69]

Great video as always, never seen one of this gadget inside. Thanks Vince.

[@barbaravintson1217]

Good afternoon hope you and family have wonderful day Thank you for taking the time out to show us your video i appreciate you very much Thank you so much for doing it for people Can see it

[@Mymatevince]

Thanks Barbara 👍👍

[@rabidwasp]

I have one of these exact devices, and it works very well - it is in a basement room (Former wine cellar). It will fill up its resevoir in about 3 days (Longer if it is hot, dry weather). After about 12 months, the fan gave up the ghost, so I replaced it with a similar one from my bits & pieces box (Which was much quieter running).

[@P2PC]

Hey vince, Student of electronics here. That is indeed a peltier element or otherwise a thermo-electric (TEC) element. The logic is that one side will become cold and the other side will become hot. This happens due to that the heat energy is removed from one side of the element and placed onto the other side of the element. The reason this works is because the element uses many semiconductior diodes in series within the ceramic package. To keep things simple, the flow of electrons through the semi-conductor juntions acts as a one-way heat valve. The flow of current through the junction pulls heat enery out of one side of the semiconductor package and places it on the other side. Each side of each semiconductor is bonded to each side of the ceramic plate. These devices by nature draw a high current due to the ammount of energy needed to pass through the semiconductor junctions in order to exaggerate the thermo-electric effect. The reason for the failue of the TEC element is because one of those semiconductor jucntions has failed making it open circuit. You manually were able to jump the faulty junction by touching one of the tracks. This is not an ideal repair loing term as this means each semiconductor jucntion is now receiving a higher volatge than it is rated for (as voltage in series devides between all connected components). The root cause of the failure is likley due to an imperfection with the failed semiconductor at the time of manufacture rather than being over heated. The imperfection with the seimicionductor likey introduced a higher resistance which got higher over time as the imperfection began to degrade to the semiconductior, this probably got to a point where it was getting significaly hotter. The thing with silicon is that as it heats, it can pass more current meaning this snowballed untill the semiconductor blow open circuit. Thanks for the amazing content as always mate!

[@Mymatevince]

Excellent, thanks Power2 for the great explanation 😎

[@P2PC]

@@Mymatevince No problem man. Keep up these awesome videos. You’re doing great work educating people on the inner workings of everyday (and unusual) electronics from a standpoint of which anyone can understand.

[@sublimationman]

Peltier junctions are really cool. I once made a large cooler for storing temperature sensitive epoxy in using 8 of the largest ones but they are not very energy efficient. I have known a few family members that tried the Peltier dehumidifiers but they never really worked. So a mini desktop fridge they are OK for but not for dehumidifiers.

[@brewmagoo3683]

Hey Vince, those peltier units are in a lot of items where I live in Canada, ie; counter top wine coolers, as well as water coolers and (koolatron) picnic coolers. You can reverse the hot/cold sides by switching polarity. Great video !! Keep up the great content

[@Angelawl]

@Mymatevince cold air is supposed to come out from the top of this dehumidifier so maybe the Peltier module should have been placed the other way around. Great fix nonetheless, and another great video,congrats!

[@Mymatevince]

Thanks for the comment Angelol, but I think the hot air is supposed to come out of the top to cool down the larger heatsink on the hot side of the Peltier plate, otherwise the hot side of the plate will end up heating the cool side of the plate if the air isn't expelled from the unit. Apparently they produce more heat than they do produce cold hence the bigger heatsink on the hot side 👍👍

[@Angelawl]

@@Mymatevince I don't have a dehumidifier so my only experience being a singular interaction with it could be why I got it mixed up. Therefore I believe a second acknowledgement is due since I learned sth new aswell. Thanks for taking the time to reply and explain.

[@taibataiba6461]

@@Angelawl sssss

[@Hitek146]

Also called a Peltier Junction. Widely used in "refrigerator coolers", that aren't actually really refrigerators. Consume a ton of current for little effect, and generate a ton of heat for the little cooling they provide. They were also very popular in the Pentium II/III days for cooling slot processors... Edit: If I recall correctly, you can also heat one side and cool the other, and the Peltier Junction will produce current, as in, they also work in reverse...

[@mrjsv4935]

Interesting device that peltier element. I remember from school, I think 8th or 9th grade physics class in late 80's, teacher showed once a peltier element, which created electricity just from the heat of a hand. That was pretty cool and memorable experiment :)

[@martinmalone6324]

got 2 of these not the same make, but there brilliant, was a fiver more, work like a charm, no more condensation on my widows anymore upstairs.

[@buildyourdream8127]

With enough cooling on the hot side you can take the cool side down to -35, what i meen is that the cooling fan on the hot side is way to small for it to work properly. Keep up the good work, i realy like your videos.

[@g7eit]

I had several of those on my boat. They’re brilliant. The peltier device works the other way too. If you produce big team changes it produces voltage.

[@wisher21uk]

Peltiers are brilliant Vince you can have fun with them thanks for the upload

[@MrOmiez]

After reviewing the scene, yes the Peltier needs to be the other way. The air entering has to encounter the cold side and it will create condense that will drip.

[@markpirateuk]

I have a Peltier wood stove fan, as the stove heats up, it generates electricity to drive a small DC motor to circulate the hot air in to the room. They are also used in those mini fridges, a very similar setup to that dehumidifier.

[@1TimothyFourTen]

Thanks for sharing. I had that exact type of dehumidifier - it goes by the name "Pro Breeze" LOL here in the US. It worked great (I thought) for about 3 months and then it wouldn't turn on. I figured it was because the automatic sensor that turns the unit off when the tank is full of water, sensed the tank was full of water, and switched the unit off, but it happened to switch off at night while I was sleeping, and so I didn't get to it in sufficent time -- i guesssss??? I don't know, but that happened twice on two Pro Breeze's - in exactly the same way. This was fun to watch - I thought - is it just me who finds peeling off hot glue around the peltier plate so satisfying? And why? It's the "little things" in life, I guess. :)

[@LIFEbytheMEKONG]

Vince, a few things: yip, new heat sink compound required, basic electrical theory, the current is not pumped into anything, current is drawn by the appliance and provided not faulty will only draw the correct current as determined by voltage supply and resistance of appliance, setting your power supply to 5 amps purely means you are limiting the current to that, you could set that to 10 amps but the device will only draw the current it requires, and lastly you are using this at the wrong time of the year, believe it or not the humidity outside in winter is lower than in summer, however if your house is hot and you have laundry drying, kettle on etc then the hot air inside has the ability to hold more moisture and will deposit this moisture on cold surfaces, that's how this works, I lived in a house with no double glazing and was very moist inside, my sash windows got soaking wet during the night from just breathing, I had one of these and I had to empty it every day, however a newer house with double glazing, insulation etc will be much less humid inside and this will have pretty much nothing to collect, try it in your bedroom overnight with all windows closed.

[@Mymatevince]

Thanks Paul 👍👍

[@Anybloke]

I've got a large, mains powered dehumidifier which I use in my bathroom after every shower in winter. Works superbly. Leave it on for an hour and it thoroughly dries out the room. It leaves about an inch of water in the collection tray. For a damp cupboard I find that a crystal type moisture trap works best.

[@paultasker7788]

I'm pretty sure some hotel mini bars use these. One huge benefit is they are very quiet and don't turn on and off in the night. The only sound you hear is the fan. For a small fridge you can get cool enough to chill drinks. My camping cool box will use one of these too. The main downside apart from fairly high energy use as constantly running is the temperature isn't very controllable and will depend on the ambient air. Use it in colder rooms and my camping fridge can drop below zero. The adjustment only seems to vary the speed of the fan.

[@englishrupe01]

Wow, cool......i have exactly the same one that has also failed. Many thanks, Vince....i am going to do the same switchover contact point fix. Cheers, Vince.

[@englishrupe01]

PS I use mine in my gun safe. Maybe mine will work.....or i will change the peltier. Mine did pull off quite a bit of water in my gun safe.

[@Sterling20073]

lookin forward to this, believe i have 1 with this problem and i've thrown a few out over the years

[@PaulRansonArt]

Great fix Vince. These micro dehum's are only really a toy and not a practical solution for humidity control. Maybe as you suggested in a damp cupboard or caravan or boat. 😃😃

[@josephdoiron8376]

That peltier device is what powered the voyager 1 and 2 space craft. It used the cold of space and the heat from a plutonium pellet to create the current in the device. I believe its called a radioisotope generator. They also use that peltier device to make little fridges for your vehicle you can plug into a cigarette liter.

[@Mymatevince]

That is so good. I'm going to Google it, thanks for sharing 👍👍👍

[@josephdoiron8376]

Its called tge Seebeck effect. Two dissimiliar conductors connected together. One heated and the other cooled produces a current.

[@marcellipovsky8222]

Hi Vince, I have one of those at home, but a bigger unit and it did collect some water over time. Not much but it did. I used it during the cold winter nights when water condensed on the windows. You can test it in the bathroom where the humidity is very high. Though, given the price of electricity, they are not very efficient.

[@Mymatevince]

Thanks Marcel, I love the idea of these Peltier plates and the clever uses people have put them too (like the hot stove fan), but like you mention the inefficiency of them is a real shame 👍👍

[@marcellipovsky8222]

@@Mymatevince Yeah, LTT did a experiment with avery large one. Didn't go that well. kzbin.info/www/bejne/qYjVoqyHjMubqNU

[@marcyd2007]

Dude, the sealer around the edge of the Peltier Plate is to stop condensation getting in between the two plates and causing corrosion. Also, the fan performs two jobs, it circulates air as you correctly pointed out, but it also keeps the hot the side cool enough that it doesn't melt plastics etc. The device doesn't require any heat from the Plate, it's just a bi-product of producing the cold, so it's ok to cool the heat side down, it doesn't effect the condensation that it needs to produce in order to do its job. If you want a bigger challenge on this sort of device, there are slightly larger dehumidifiers that actually have a gas heat converter and pump unit in them (like your fridge/freezer) but they work on the same principal, heat on one side, cold on the other for condensation. They have a proper radiator with all the metal fins like your car and they are way more effective too. The Peltier Plate models are not really that effective once you've tried a proper one. I empty the 1.5L tank on mine once or twice a day depending on the time of year.

[@Mymatevince]

Thanks Marc 👍👍

[@eathenalexander2836]

Very interesting. Just as you did, I learnt a lot of new things. Thanks for the great content

[@koz]

Peltier plates are pretty clever. When a current is passed through one, they get warm on one side and cold on the other. You can actually make a small beercan size 'fridge' out of them :)

[@GboabGman]

That thermal paste should have been replaced and covered the whole of both sides of the plate. will work so much better.

[@xXBeefyDjXx]

Awesome fix video Vince. Peltier coolers are not very efficient, and are expensive in larger sizes because of the cost of the metals used and energy required to power them. The major problem is that to get really cold and overcome the energy of the heat generated on the other side you often require a lot of cooling not just a fan. Peltiers can get into the minus figures, they can even ice up if cooled enough! In an ideal world the fan on this unit would need to be larger and draw more air so that it can really pull the moisture out of any room regardless, since that would bring hot and cold sides down a bit more and enable the air to lose moisture faster + more air throughput... Perhaps it's worth testing it with a faster fan at the expense of the noise?

[@zierlyn]

The answer to your question of "If I put this in a cold room, will the cold side go negative?" is yes. Just think of it in terms of Conservation of Energy. The Peltier device moves thermal energy from one side to the other (the efficiency is actually rather bad, mind you). It uses electrical energy to create a temperature differential. That differential will always be a specific amount depending entirely on the voltage and amperage (a.k.a. wattage). One thing you might find interesting (yet daunting at first glance) is a Psychrometric Chart. It's a tool used in HVAC that helps someone calculate relative humidity. The key thing to understand is that humidity is literally the measure of the volume of water molecules in the air, measured in litres. The warmer the air is, the more water it can physically hold in it. Relative Humidity (which is what the weather report tells you) is the percentage of the maximum amount the air is able to hold at that temperature. When the air outside is warm and humid, and the temperature suddenly drops, you get fog, because the specific volume of water in the air at 60%RH at 25°C outside air temperature is well over 100%RH if you take that same volume of water at 15°C outside air temperature. This is why your skin dries out in the winter. Because the specific volume of water that below 0°C air is able to hold at maximum is below 20%RH once you warm that air up to room temperature (human comfort level is between 40%RH and 60%RH). Armed with that knowledge, there is also a "Dew Point." A Dew Point is the temperature a solid surface needs to be in order for condensation to form upon it. The Dew Point is directly tied to the specific volume of water in the air (and air pressure, so your elevation above sea level affects it). So, now you have all the tools necessary to figure out: how much of a temperature differential you require to actually cause condensation, relative to how much humidity is likely to be in the air, given the air temperature outside relative to inside your house. Bonus: Using the Psychrometric Chart, I can see that: If your Peltier is able to get the cold heat sink down to 5°C, if your indoor temperature is 20°C, you would need at least 38%RH indoors, which (barring additional water vapour sources inside like humans or a steaming bath) would require it to be at least 5°C and raining outside to get any condensation at all in the dehumidifier. If it's 10°C and raining outside, it's probably around 55%RH indoors, and the dehumidifier should be able to get some condensation. Also likely is that it's a crappy dehumidifier, the fan is too strong (it's evaporating the condensation through friction from the moving air before it has a chance to run off).

[@Mymatevince]

Really interesting reading that Zierlyn, thank you 👍

[@sonjamuller399]

Hi Vince the hot side should be on the heat sink side .Just turn the red and black wire around on the pc board

[@smallg9109]

he knows, there's 2 heat sinks, a smaller one that is used on the cold side to funnel the water and the bigger one inside the plastic casing that is attached to the fan to disperse the heat. during the video vince is just using the smaller heat sink cos it's easier for quick testing.

[@logothaironsides2942]

These are okay for steamy bathrooms and kitchens and we have one for the camper . We played with a peltier for science projects and you can add hot one side cold the other and get electricity from the 2 wires, enough to charge a battery using a car usb adapter thing. These same type of modules are used in those simple coolers you see sold for dorm room use. I think the one we have is 12 degrees below the ambient.

[@taylty]

Hey Vince, I live in a climate that is very humid in summer and very dry in winter and ok in spring and autumn. I have a heavy duty dehumidifier that really only pulls moisture out of the air in in the worst months of humidity, it kicks out a lot of heat so it is mainly used in our lower lever family room.

[@Crumbleofborg]

I would like to see you try the peltier element the other way up, just in case we've misunderstood the way it works. After all, it was the other way up originally.

[@dawn5227]

I have one of these, and in my old nearly 100 yr old house that the walls are not insulated it does well, it usually fills up in a day or 2 depending on the humidity in the air. They are not going to be as good as the large dehumidifiers but as a mini option it does help reduce some dampness.

[@guidomersmann9744]

Peltier elements are quite in efficient. They are often used in mini fridges. These crappy 2-3 0.33l can sized stuff you can usually win and have a huge company logo on it. For a fridge a version with coolant and compressor is the best option.

[@aleksandersats9577]

The peltier needs to be very well cooled in order for it to get cold enough to dehumidify. The more colder the hot side of the peltier is the colder the cold side will be. What a peltier does is it takes the heat energy from one side and moves it to the other, that's why one side is cold and the other is hot. It's taking the heat energy from the cold side and moving it to the hot side. Now the reason why it's better if the hot side is colder is because it can also do the reverse if the hot side is not well cooled, by moving the extreme heat back into the cold side. Try having a really good heatsink on the hot side and you will see a huge difference in how it performs

[@Mymatevince]

Thanks Aleksander 👍👍👍

[@Riggy2201]

I've got one of these (Branded Pro Breeze). Using it to make biltong inside a nylon wardrobe/dryer. It is collecting water, but so slowly as to be ineffective. I bought hygrometers to monitor humidity inside and out. 50 - 58% inside and out at 20c. No difference. Found your vid whilst looking for some sort of actual performance stats. FYI it's supposed to work above 15C. I've ordered a 15w filament lamp instead. I knew about peltier plates already. Can be used in reverse to generate electricity from temperature differences like can be done with refrigerants.

[@DolittleMccoy]

I had this same mini dehumidifier. It worked great for a while. After about three months I went to empty the water due to it being full and it never came back on. It may have been because I kept it on continuously for a long time.

[@PADR]

I have two these running in my caravan when we aren’t using it and they produce quite a lot of water. They just keep the humidity levels to a reasonably low level. The problem is that during winter when its damper the ambient temp is low which means the unit forms ice on the chiller plate. This renders the water collection null and void. I think more expensive units heat up to disperse the ice from time to time. They’re ok for what they are.

[@bamboozledsoftware]

I'm going to attempt make a fitted fridge in my boat with Peltiers, been thinking about this a while now, great little components.

[@trance_trousers]

Interesting! I've used a dehumidifier for the last 10 years or so but had no idea what was in them or how they worked. Mine is a lot bigger than this one, maybe twice as big. I live in a tiny studio flat and use it to dry my washing! I put all my wet clothes and things in the bathroom, close the door as much as I can, and leave the dehumidifier running overnight. In the morning all the washing is dry! I can get way more water in the container than the one shown here. This one looks a bit crap to be honest! Mine works just as well in the winter as it does in the summer.

[@terminationshock1356]

I once had a water leak in my apartment where the wall was full of water. The drier the landlord gave me was a big heavy duty one (about the size of a half.sized fridge) and very loud. It went on 16 hours per day and still the tank needed days to be filled. I am not surprised you barely find anything with this small one after 3 hours. Probably it does what it should but the little water it collects evaporates again in the dry air of your home

[@paultasker7788]

I had a Maplin version of this. It did collect a small amount of water but was not very effective and used a continuous 80 watts of power. I replaced it with a compressor based one which used no more power and was 10x more effective. Only needed to run that for 2 hours or so as opposed to 24 hours. Also in winter central heating dries out the air so the humidity will be quite low.

[@bernd-das-brot]

I have the same device, it works perfectly and has been for over 10 years. We have it by the sink in the kitchen because mold has always formed there on the outside wall in winter. the dehumidifier only works well if there is humidity, in winter the heating air is quite dry. small calculation example: at 0°C and 98% RH air humidity there are 4.75 g of water in 1 cubic meter of air. If this air is now heated to 20°C, it is suddenly only 27% RH. This dehumidifier achieves the 250ml/24h, according to the information in the instructions, at 30°C and 80% RH, i.e. a good 25g/m³, so it's no wonder that it doesn't perform to its full capacity in dry heating air. we empty the container once a week, a lot of dishes are washed by hand, there are about 200ml in it, mostly around 100ml.

[@Mymatevince]

Thanks Tom 👍👍

[@scottfirman]

We had a cooler that used this set up. I noticed it didn't work well in a hot vehicle or the summer when it was very warm. Those things only lower the temperature about 20 degrees cooler than the outside abiant temperature. I did notice when you packed a few freezer packs in the cooler, the temperature generally stayed cooler. You were NOT supposed to put loose ice or water in the cooler because it will short it out.

[@SardiPax]

I once stacked 3 Peltier devices. With a heatsink, I was able to freeze water on one side in seconds (a few drops). Not sure 5'C is really enough to get much condensation unless the humidity was very high. Perhaps a better heatsink on the hot side would get a slightly higher temperature differential and improve the function slightly.

[@Mymatevince]

I was just told about stacking them from another viewer. That's sounds very interesting...instant ice maker👍👍

[@JaysElectronicTinkerShack]

peltier plates are great things for projects cool bit of kit ive fixed a few things with them dunno if u have seen stove fans but thats how they work the heat from the fire goes to the peltier and creates voltage to run the fan motor

[@Mymatevince]

I haven't but others have mentioned them here. What a great little idea that is, to blow the heat around for free! 👍👍👍

[@JaysElectronicTinkerShack]

@@Mymatevince aye witchcraft those things are lol

[@MarcelSchr]

Peltier elements are my absolute favorite components, you can use it to cool, heat or even generate electricity (extremely inefficient). In my opinion, the aluminum cooler is much too small for optimal operation.

[@ballsrgrossnugly]

I'd love to make a house out of these things, using the temperature difference between the inside and outside to generate a voltage and charge a battery, but you look at the cost of these per square inch alone and your house would be a million dollar 2 bedroom unit. But I would love to see how much juice a whole house could generate in the end, at least experimentally. EDIT: maybe blowing the output of your heating or cooling system onto a plate made of these with the other side connected to a heatsink exposed to the outside air... at least you're reclaiming a bit of the wasted energy from the aircon!

[@johnc007]

Try putting the dehumidifier on the window seal at night and close your curtains. On a cold night the area between your windows and the curtains should get fairly humid. Great place to test the device.

[@jeffstation70]

I've got a similar one of these in my loft-office. Mine does pull moisture from the air. It did freeze over inside during the last cold snap though. Now I know why!

[@dodgydruid]

I have used Peltier's, back in the day of being part of the 3ghz AMD Barton single core overclock I used a Peltier a 240w one sandwiched between a cold plate to the CPU and a waterblock attached to the hot side, it was immense problems creating condensation around the CPU and you had to block it off with dialectic grease and make from styrofoam a "jacket" to help insulate and barrier more precipitation forming inside the PC cavity. As long as you have something to carry off the heat generated by the "hot" side, the cold side can freeze nicely creating great concentrations of sub zero temps, I did try with a 120w one like the one in the machine there but they were gutless in terms of creating decent hot and cold sides.

[@Mymatevince]

Cheers Ian 👍

[@Kinibal]

I had this exact model in my university dorm. And thank God for it! Without it my clothes would smell like mold.

[@Dave64track]

Great video and quite interesting on how these dehumidifiers work. A quick test to see if you have a lot of moisture in the air is put a plate in the fridge which it at around 4-5 degrees leave it in there for a few hours to get down to temperature and when you bring it out you will get condensation on it if your room humidity is high like when you don't have double glazing and it's cold out side you get moisture on the windows. Not a lot to go wrong with these devices really now you've shown what's in side. I guess the larger one's have a compressor in like a fridge to get the heatsinks cold for the moisture to condense on and hence they cost a few hundred pounds.

[@Mymatevince]

Thanks David 👍👍

[@fredcooper2063]

.... Nice job, Vince, great video!! Just a tiny aside, much fun as dismantling components to see how they work is, or if they are repairable, some components, ( ceramic power transistors, some i.c's, etc,) have VERY toxic substances { beryllium} inside... Be careful!! Cheers, Thanks for the videos!!

[@MrGrumpygit488]

Recently bought one of these from Amazon for £18, the fan is a bit noisy but it collected 100ml of water in less than 24 hours. The spec sheet says it works best if the air temp is 30C & the humidity is around 80%.

[@reggiedixon2]

I have a similar device from Amazon, I only switch it on when I am drying clothes indoors near a heat source. It seems to suck the moisture out of the damp clothes very nicely. 10 ml an hour in these circumstances is a massive underestimation. I also get ice forming on top of the water container.

[@Mymatevince]

Thanks Reggie 👍👍

[@andymouse]

Not boring at all as people's reactions when they discover 'heat pumps' or 'Peltier's' or 'TEG's' for the first time is always the same, delight and wonderment. They are quite robust but are semiconductors at the end of the day. They generate a heat differential between hot and cold side so the quicker you get the heat off the hot side the better the efficiency is going to be, i could bore you and go on but I won't as wikipedia will tell you all you need to know suffice to say they draw a lot of current !....cheers.

[@TheSkaldenmettrunk]

I never ever have heard of that or seen anything like that thing. Very interesting.

[@rickhall19]

I use a similar unit in my spare, irregularly used car during the colder months. Ideal for collecting internal condensate, although I must remember to turn it off if the temperature approaches zero, otherwise the unit ices up.

[@bones1225]

Hi V, you found the fault. Skills. I would have failed diagnostically.. Truth is that wee peltier , per lxb, cannot do that volume of room in terms of cubes.

[@m.brillon8808]

Awesome mate! I really enjoyed your excitement as you discovered something new. Its always fun discovering new things. Yeah pretty neat little device. Thank goodness for them. It keeps my beverages cold when I'm camping. I love that cooler bag. Take care from Canada eh!

[@kam_mil]

I have one but slightly bigger, and it actually collects tens of mililiters of water, but I live in a very humid place (poland) where the relative humidity is 90% most of the time. I would recommend paying a bit more for a heat pump model tho, these work much faster, and collect liters instead of mililiters

[@CasualSpud]

Eastern Canada here.. We should fill these in hours.. Not weeks. More Amazon crap from China

[@meetoo594]

Yup, mine is about 3ft high and does ozone sterilization and ion generation as well. If the tumble drier is on it collects a lot of water, probably a liter at least in a few hours. It causes my eyes to dry out and sting if im in a room its sucked all the moisture from. Its pretty good. Not sure if its a Peltier or heat pump one though.

[@kam_mil]

@@meetoo594 that's amazing. I also have a heat pump condenser tumble dryer, but mine doesn't really help pull out the water from the air, but it of course condenses lots of it out off clothes.

[@meetoo594]

@@kam_mil Having watched the rest of the video, mine puts out cold air from the fan vent unlike vinces one which puts out warm air. Maybe mine is a heat pump one?

[@kam_mil]

@@meetoo594 easiest way to check is to ilsten if you hear a compressor turn on, they have a very distinctive sound

[@catlikelemur2760]

Hi Vince stick it in the rolls for a couple of hours with the doors closed bet you will see it work in there 😊

[@Paul-ib5xv]

I have a decent one from Screwfix and I use it instead of our tumble dryer. Put the clothes on an airer in a room with all the doors and windows shut and it dries the clothes. A lot cheaper to run than a tumble dryer.

[@Brianck1971]

Vince the heatsink goes on the HOT side not the COLD side. Then the cold side will get proper cold and you will get water in the container.

[@Mymatevince]

Hi Brian, I was only testing that in the video to see which was the hot and cold on the replacement Peltier plate. When installed in the dehumidifier the hot side went to the bigger heatsink on the back with the fan and the cold side to the smaller one at the front to collect the condensation 👍

[@65bug519]

It has lost several rows in the array and the air in your home is likely quite dry as well, locate it in the bathroom and it should extract some moisture from after a shower.

[@paulstaf]

There isn't a specific "HOT" or "COLD" side to the Peltier device, you can just flip the polarity on the leads to change which side gets hot. These Peltier devices are used in small portable soda coolers used in cars and you can change them from a beverage cooler to a food warmer by switching the polarity on the plug.

[@EzeePosseTV]

HEY Vince.. The quicker you remove heat from the peltier plate hot side, the colder the cool side goes. They can create frost within seconds if enough heat is expelled from the peltier (larger heat-sink and/or a better fan applied to the hot side may work) _Rob from Scotland_

[@UserUser-ww2nj]

So somehow strap something like a computer fan onto the hot heat sink to draw out the heat ? , makes sense . When those plates are used on stove top fans they are more efficient with better designed fans with a bigger area for the heat to dissipate , more fins etc and the fan blowing the hot air away helps cool the fins

[@Rejetor]

But in this machine you don´t want the cold side to get below 0, the moisture in the air instead of condensate in the heatsink, would then freeze and turn into ice.

[@UserUser-ww2nj]

@@Rejetor Then you would have an air conditioning unit for the summer 😂😂

[@Mymatevince]

Thanks Rob, I could Frankenstein the Peltier plate to my Dyson fan and PS5 heatsink 😂

[@UserUser-ww2nj]

@@Mymatevince Where did Rob go ??

[@MrJDNJ]

I think a desert and the polar regions are the driest air places on earth (the ice and snow accumulation is leftover from different eras). For a full analysis you need a humidity meter, or wait for a rainy day when you know it's at 100%.

[@JoeBob79569]

Those Peltier coolers are often used in amateur astrophotography cameras to keep the sensor cold enough to reduce noise in the photos. And they can get down to below -20°C. Their specs often given as degrees below ambient (eg 40°C below ambient). It's possible that you didn't have the proper type of thermal paste on both sides of the cooler, or it may not have been making proper contact with the cold, and/or hot, side.

[@martijnappeldoorn8686]

You’ll also find peltier elements in wine coolers, thats where i saw them for the first time, i knew they existed but never saw one before i had that wine cooler for repair.

[@precbass]

New word 'Condensate'. or Condense if you like.😁Great fix nevertheless as usual Vince.

[@Martyn-ey9lw]

Condensate in this case would be the water collected in the tank. 😉

[@philsmith6165]

Correct. Liquids condense and the result is condensate.

[@krisgair5863]

I have the same unit, takes a looooooonnnnggg time to collect any water, also works better if you take the filter off the top, Also they work better in warm rooms as cold air holds less moisture

[@fmdof]

ive got one of these. we use it in our pop up camper. need to try and keep the moisture level to a minimal in a camper.

[@danandrei96]

had the same exact unit in a flat a couple years ago, yeah they're not amazing but the tank would fill up every few weeks so they must do something in the long run I'd say. Of course, a bigger unit will be more effecive

[@robtitheridge9708]

Vince you did say your room was not very warm warm air holds more moister . The same device is allso used in the small 12 volt fridges.

[@Mymatevince]

The room I film in was/is cold but the kitchen is warmer, but overall my house might be dry because of double glazing and the heating is on. I probably didn't give this thing a fair chance.

[@TrustNo1sz]

20 years ago, or so, we used peltier to cool overclocked computer processor. The challenge was to deal with the condensation.

[@fatbelly2438]

i have one in the shed..it sucks in half a tank of water every week..edit too add in the winter ice forms on the outside plastic slots..

[@EightBitShift]

Looks like it similar to the dew point on a weather station, I.e. the condensation only occurs at a certain temperature if the humidity is high enough.