Peltier Help - (Solar Powered Cooler?)

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Re: Peltier Help - (Solar Powered Cooler?)

Postby asheets » July 28th, 2011, 10:40 am

Incidentally, a 120W solar panel will run you about $700 USD. Probably not the cheapest thing to run a 120W peltier array.
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Re: Peltier Help - (Solar Powered Cooler?)

Postby PseudoNym01 » July 28th, 2011, 12:27 pm

Hmm car batteries seem like a good idea and I (or Dad) might have one lying around, though I would like to maybe trim down to something smaller because this project, in a perfect world, still be able to be carried to and survive a beach like enviroment, maybe a sealed battery of some form? Hmm in terms of heat sink, Im guessing Id need to create something thats big enough to cover the hot side of the peltier...hmm this bear more thinking on. Just to clarify Im not necessarily looking for a full fridge replacement device, Im not looking to create a mini-fridge per se, ideally the beers would be stored in the cooler already cold and this device would help to keep them cold (kind of an ice replacement).

UAirLtd - thanks for the calculations that helps.

asheets - I like the idea but Id really rather not stick anything in my beer. Maybe invert it? something that covers the drink on the outside?


-Pseudo
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Re: Peltier Help - (Solar Powered Cooler?)

Postby UAirLtd » July 28th, 2011, 5:28 pm

You can grab some small(ish) sealed lead acid batteries that wouldn't weight so much, and if you just want to keep already cool beer cool, then go for a 6V sealed lead acid, and run a peltier at low power. This will let you run the peltier for much longer per charge since you're not running it at as high a power.

This will also increase the efficiency since the hot side of the peltier needs to dissipate much less heat, so the thermal gradient is lower too.

As for heat sink, if you're going to somewhere with running water available, you could dump the heat into a large container of water (and remember to empty the warm water and replace with fresh, cold water every so often). Now you have a water-cooled beer cooler!
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Re: Peltier Help - (Solar Powered Cooler?)

Postby Osgeld » July 28th, 2011, 8:14 pm

^^ this

check out light bulb or building maintenance supply stores for sealed led acid batteries, they use them in emergency lighting and its probably cheaper than hoping the local big box, or radio shack has them...

also I can imagine the fun arrangements trying to watercool a cooler while at the lake, I am thinking closed loop system with rubber hoses and a coil of copper tube sitting in the lake, pushed by a fuel pump lol
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Re: Peltier Help - (Solar Powered Cooler?)

Postby asheets » July 29th, 2011, 9:08 am

re ^^^

The perfect (IMHO) thing to do is get some UPS batteries. They come pretty cheap and are fairly universal (I use them for UPS replacements, emergency lighting, and replacements for toy cars/scooters)...

http://www.amazon.com/Hi-Capacity-Batte ... 944&sr=1-6 12VDC, 3.0AH
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Re: Peltier Help - (Solar Powered Cooler?)

Postby PseudoNym01 » August 1st, 2011, 11:01 pm

UAirLtd two questions,

Can you either show me the calculations you used to calculate the heat/energy transfer and how all of the works? Second you mentioned that I need to make sure that too much juice wasn't being pumped into the peltier devices, how can I do that? Voltage regulator do you think? Or is it something much more simpler?

My revised idea is now to possibly work with an increased number of smaller peltiers, that way the hot side on any one device isn't to much of a problem.

-Pseudo
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Re: Peltier Help - (Solar Powered Cooler?)

Postby asheets » August 2nd, 2011, 9:05 am

I once did that by using the can (of Pepsi, in this case) as one of the heatsinks. On the other side, I placed a conventional computer heatsink and fan. I then hooked the entire thing to the +12vdc line of a computer power supply.

Unfortunately, I hooked the peltier up backwards and ended up cooking the Pepsi fairly quickly (I left the assembly unattended).

PseudoNym01 wrote:asheets - I like the idea but Id really rather not stick anything in my beer. Maybe invert it? something that covers the drink on the outside?
-Pseudo
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Re: Peltier Help - (Solar Powered Cooler?)

Postby judas79 » September 23rd, 2016, 5:30 pm

I know this thread is old but I'm trying something similar. How do you hook the pelieirs to the Solar Panel? My solar panel is 100 watts 18 volt output. My peltier is 12v 60 watt and I'm also using a 12v 300mA water pump to circulate water through a heat sink; also using the solar panel through a cheap solar charger controller. I got the pump running off the 12v battery charger output, only when there was a peltier load on the "light" output on the controller, but there wasn't any way to get the peltiers working, in either the battery charger or the "light" outputs. I did switch things around to see if they worked using different outputs. I'm fearful I might have destroyed the peltiers when I hooked two of them directly to the 18volt solar panel, when I became frustrated with the controller. They did get cold and hot when I did this for a while.....but now not!
I have since found out that the "PWM" outputs from the controller, are not a good way to power the peltiers. I'm going to order more peltiers since, as I mentioned above, I may have destroyed my first two. I do have a second 100w solar panel I can use in the project, and your input would be appreciated on the correct way of powering the peltiers using solar panels.
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Re: Peltier Help - (Solar Powered Cooler?)

Postby judas79 » September 27th, 2016, 10:01 pm

bump "help please"
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Re: Peltier Help - (Solar Powered Cooler?)

Postby k-ww » September 28th, 2016, 7:49 am

You need a circuit called a 'buck' dc-dc converter - 'buck' circuits drop a higher DC voltage to a lower one.

It needed to be of a higher power rating than your solar panel - I would look for one that has a 150W output rating,
or 12 amps output current or more for a single 100W panel.

Make sure it has an input voltage range that can handle the voltage from the panel.

You should also have a fair sized cap across the output of the panel, since 'buck' circuits have a high instantaneous current draw,
and the cap [1000uf or more at 25V or higher] help the panel handle this.

Connect this circuit [buck converter & cap] between the solar panel and the Peltiers,
and don't use the solar charge controller - it's meant to charge
batteries, and not run something like the Peltiers directly.
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