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Peltier control

SWISL

New Member
Turned a broken wine fridge into a humidor. Works good but I can’t get the temp high enough. I need 70°F but it only gets to mid 60°F with temp dial at warmed setting. If I unplug it the temp can get into the low 80’s. No good for the sticks. I’m thinking the easiest fix would be to add a resister in series with the 12vdc feed to the Peltier. But was wondering if there is a better fix to changing the temp range of the unit or is this the best way. I don’t see a need to mess with the temp much once I get it in range. A single PCL border everything. Mostly analog. Some logic but nothing programmable. A small pan with a switching supply feeding the analog driver circuit. Connected are the temp pot, a thermo sensor, an led light 2 fans Any thoughts are appreciated.
 

OldTechie

Member
You didn't say how much power your Peltier element needs. And if you're only using a single Peltier device, and running it at full power doesn't raise the temperature enough, then you probably need two, or possibly three devices. That's pretty important to know before continuing with anything specific to use as a controller.
Here's a link to a project that could be a starting place for you to consider. It uses standard, reasonably cost, readily available components. You can get all the components in through-hole packages (not SMD) from Digikey, so no difficult soldering needs be done.


According the the write-up, it's capable of handling up to 100W of devices, so if you need more than two 50W Peltiers, then a more powerful controller would be necessary.

Cheers,
DaveM
 

SWISL

New Member
You didn't say how much power your Peltier element needs. And if you're only using a single Peltier device, and running it at full power doesn't raise the temperature enough, then you probably need two, or possibly three devices. That's pretty important to know before continuing with anything specific to use as a controller.
Here's a link to a project that could be a starting place for you to consider. It uses standard, reasonably cost, readily available components. You can get all the components in through-hole packages (not SMD) from Digikey, so no difficult soldering needs be done.


According the the write-up, it's capable of handling up to 100W of devices, so if you need more than two 50W Peltiers, then a more powerful controller would be necessary.

Cheers,
DaveM
Thanks Dave, you are correct in that I left out some details. The Peltier is a 12706. Specs say 6.4A at 14.4VDC. Says about 50W at 50°C (77°F). 2.5 cf fridge and only one device. My problem is it gets too cold even at warmest setting of the temp dial. The dial has no temp markings. I’ll check out the links you sent as well.

Best, Benn
 

SWISL

New Member
Thanks Dave, you are correct in that I left out some details. The Peltier is a 12706. Specs say 6.4A at 14.4VDC. Says about 50W at 50°C (77°F). 2.5 cf fridge and only one device. My problem is it gets too cold even at warmest setting of the temp dial. The dial has no temp markings. I’ll check out the links you sent as well.

Best, Benn
And the math doesn’t work on the numbers they give in the spec sheet but I intend to make measurements before I attempt anything.
 

SWISL

New Member
A simple approach use a cheapo T controller that senses actual T, compares against
user setpoint, and controls Peltier.



Regards, Dana.
Thanks Dana, though my T levels are pretty good, I’ll take a look very helpful, thanks.
 

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