DIY Thermoelectric Peltier Refrigeration

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Nightjar

Nightjar

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Keeping the 12V portable fridges cool during higher ambient temperatures while away remote camping has always been a challenge.
Received a DIY kit today and first thoughts it maybe a winner.
Assembled the kit and a temporary trial in the shed I was very surprised.
Will make up a holder to direct the cool air onto the workings of the 39L Engel and if results are positive will purchase another for the 60L.
The ambient temp today was only in the low 20C's but with the unit powered up the resultant airflow got down to 2C.
If all goes well, the couple of extra amps required to power unit should be offset in shorter run times.
Time will tell.
 
Nightjar said:
Keeping the 12V portable fridges cool during higher ambient temperatures while away remote camping has always been a challenge.
Received a DIY kit today and first thoughts it maybe a winner.
Assembled the kit and a temporary trial in the shed I was very surprised.
Will make up a holder to direct the cool air onto the workings of the 39L Engel and if results are positive will purchase another for the 60L.
The ambient temp today was only in the low 20C's but with the unit powered up the resultant airflow got down to 2C.
If all goes well, the couple of extra amps required to power unit should be offset in shorter run times.
Time will tell.
Click to expand...
I would think that you could get away with using a very small unit because even dropping the Air Temp by 5* make a huge difference, So using one small one that could cool the Air by about 10*c would make the fridge run a lot less and if you are seeing an 18* drop then that would drop a 45* temp down to the mid 20's,

NJ, I gotta Ask although it might be a dumb question, But does your fridge struggle to stay cool in 30 to 40* Temps ??

Another thing you could try is adding one or two small computer fans to the Air vents because the only down side to the petlier systems is they drip water So It might pay to mount it on the End Vents and not the top vents, Computer fans use less than a 1/4 of an Amp or less,

good luck mate, let us know how it all works out, That's a great Idea,

J.
 
Ridge Runner said:
NJ, I gotta Ask although it might be a dumb question, But does your fridge struggle to stay cool in 30 to 40* Temps ??

Another thing you could try is adding one or two small computer fans to the Air vents because the only down side to the petlier systems is they drip water So It might pay to mount it on the End Vents and not the top vents, Computer fans use less than a 1/4 of an Amp or less,

good luck mate, let us know how it all works out, That's a great Idea,

J.
Click to expand...

RR, The Engel handle the summer very well, meats frozen and beers cold but obviously the higher the ambient the higher the thermostat.

Condensation is rarely a problem in our goldfields it is extremely rare to wake up to morning dew. Noticed the condensation on the unit yesterday but what I have in mind has it under control. (Going to collect it in my water bottle. :playful: )

The computer fans are all but useless they blow hot air and do very little to help fridge.
 
Nightjar said:
Keeping the 12V portable fridges cool during higher ambient temperatures while away remote camping has always been a challenge.
Received a DIY kit today and first thoughts it maybe a winner.
Assembled the kit and a temporary trial in the shed I was very surprised.
Will make up a holder to direct the cool air onto the workings of the 39L Engel and if results are positive will purchase another for the 60L.
The ambient temp today was only in the low 20C's but with the unit powered up the resultant airflow got down to 2C.
If all goes well, the couple of extra amps required to power unit should be offset in shorter run times.
Time will tell.
Click to expand...
Can you put some pictures up and maybe a link please ?
 
Ctx, Can't fathom how your third item 3801595017 can be a cooler the fans are only blowing ambient air?
The tec1-12706 heatsink thermoelectric plate isn't included. Maybe only a drop of a C or two from surrounding ambient temperature?

Here are a few early pics before I build the finished product.

1569573738_cooling.jpg


1569573767_cooling2.jpg


1569573824_cooling3.jpg
 
NJ it will be interesting to see how much more power this set up uses, Although I was impressed with how fast that little 35L Snomaster works it is a power hungry SOB, but then it seemed to settle down after a few days and eventually started to use less power,

They are designed to work in seriously hot environments and have very high temp cut off settings and they are second to none when it comes to cooling, but I think it would need a real good power supply to keep it happy,

this idea of yours might add a couple of amps to you normal power draw but I think it might add a few more years to your fridges service life,

Are you fitting it to the big Engel first or the small one ?,

J.
 
Good morning RR,
I'm going to test it with the 39L first, this old girl is our main freezer (-10/-13 C) when we head bush, so she runs often and being 17yo draws more power.
Will compare running times and current draw with and with out.
Will wire the Peltier into the Engel running times.
I see they recommend leaving the "hot fan" running for a short period of time after shutdown. Maybe Jaycar may have a bit of electronics to allow this or you may know of something. Maybe an overkill?

Cheers
 
Nightjar said:
Good morning RR,
I'm going to test it with the 39L first, this old girl is our main freezer (-10/-13 C) when we head bush, so she runs often and being 17yo draws more power.
Will compare running times and current draw with and with out.
Will wire the Peltier into the Engel running times.
I see they recommend leaving the "hot fan" running for a short period of time after shutdown. Maybe Jaycar may have a bit of electronics to allow this or you may know of something. Maybe an overkill?

Cheers
Click to expand...

Just an Idea, But what about wiring it in to the Thermostat wires on the fridge so it powers up when the fridge does and shuts off when the fridge is doing it's off cycle, I know it's not the same but it would keep the power draw to a minimum ??.

J.
 
Grab a medium size capacitor and wire it across the fan , play around with size as to get a delay time on the fan, stick a power diode before it so as it doesn't feed the thermoelectric plate as well......just a thought
 
Ridge Runner said:
Nightjar said:
Will wire the Peltier into the Engel running times.
I see they recommend leaving the "hot fan" running for a short period of time after shutdown. Maybe Jaycar may have a bit of electronics to allow this or you may know of something. Maybe an overkill?

Cheers
Click to expand...

Just an Idea, But what about wiring it in to the Thermostat wires on the fridge so it powers up when the fridge does and shuts off when the fridge is doing it's off cycle, I know it's not the same but it would keep the power draw to a minimum ??.

J.
Click to expand...

RR, I wasn't very clear with my post (Will wire the Peltier into the Engel running times.) Meaning yes, will wire it into the Thermostat so it starts and stops with fridge.
 
ctxkid said:
Grab a medium size capacitor and wire it across the fan , play around with size as to get a delay time on the fan, stick a power diode before it so as it doesn't feed the thermoelectric plate as well......just a thought
Click to expand...

Feel sure there is a way if required. Their mention of delaying the shutdown of the "hot" fan is referring to when the Peltier is used as a stand alone cooler mounted in the side of an eg: icebox.
Hope to experiment in the coming week.
 
Nightjar said:
Ridge Runner said:
Nightjar said:
Will wire the Peltier into the Engel running times.
I see they recommend leaving the "hot fan" running for a short period of time after shutdown. Maybe Jaycar may have a bit of electronics to allow this or you may know of something. Maybe an overkill?

Cheers
Click to expand...

Just an Idea, But what about wiring it in to the Thermostat wires on the fridge so it powers up when the fridge does and shuts off when the fridge is doing it's off cycle, I know it's not the same but it would keep the power draw to a minimum ??.

J.
Click to expand...

RR, I wasn't very clear with my post (Will wire the Peltier into the Engel running times.) Meaning yes, will wire it into the Thermostat so it starts and stops with fridge.
Click to expand...
i'm thinking :idea: it might not reach maximum potential temp if it is being switched ,i am looking forward to see your results :Y:
 
Look like moving on to plan "B".
Using a multi meter I tried to find a 12V tapping point after the thermostat to fit the Peltier. There wasn't one with easy access and was feeling a little nervous poking around
thinking I may pop something. Ran the fridge and it cycled every 2 1/2 minutes for two minutes. Temporarily ran the Peltier pumping the cool air into the engine room, cycle time stretched out to 4 minutes, run time still two minutes.
The old Engels have two separate plugs 12V & 240V and there are a couple of common wires so only one plug can be connected at any one time. As you would be aware Engel brought out later models with two plugs and auto changeover from 240V to 12V. (Another story another day, I blabbed to an Engel engineer about my auto changeover. Maybe a millionaire now if Id patented it.?
This actually caused many electronic failures (mostly blown capacitors) when owners had their fridge hooked up to both their Genny and 12V. They could start their Genny and walk away, when it run out of petrol the 12V kicked in. Problem is when and engine is running out of petrol it surges, this caused the occasional failures.

Have ordered a couple of these from eBay and will wire Peltier to an independent 12V supply. The Peltier will fit neatly inside Engel case, cool end facing up and the hot end blowing out through bottom;

https://www.ebay.com.au/itm/AU-2pcs...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649
 

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