• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

need help finding the right part for a mini fridge/cooler

Status
Not open for further replies.

johnathon007

New Member
Im trying to build a TEC powered mini fridge/cooler and so far all has gone well but the TEC empties my battery to fast and gets colder then needed. What i want to do to fix it is put a thermosister in to limit the power when it is cold enough [around 40F] and raise power when it gets warmer. the battery im working with is a 6V like the ones found in kids cars its a 9Ah battery and i would like it to idle down to around 1-2 amps when its at ~40F [i think it runs about 6 amps just on the TECs internal resistance but cant measure because my multimeter is crap] on a side note the battery also powers a 80mm computer fan for the heatsink and a 40mm vga fan for the cold air circulation. I get around an hour if im lucky right now but id like to be able to bump that to around 2-3 or more if possible.
 

BrownOut

Banned
I use a commercially available programmable thermostat that has front panel controls and an LDC readout. It's not cheap at about 35USD, but you'll be up and running in about 15 minutes. I buy it from a local retailer. If you trying to cheap out, then you're probably looking at a homebrew controller. There are a few threads, so if you tell me how much you want to spend, I'll try to find the appropriate thread.
 
Last edited:

johnathon007

New Member
I could try to salvage an old thermostat from somewhere but i was going to try to spend under $40 for the whole thing and im at 35 right now, so maybe an analog thermostat would better fit my budget.
 

johnathon007

New Member
that all looks a bit over done for what im doing, i dont need anything really complex more of a high low is what im looking for. Just a simple full power and then a second setting to stablize the temp. i cant really find one but a thermosister that is ~0Ω at 40F and 1-2 at above that [if my calculations are right which they probably arent]
 

BrownOut

Banned
You can eliminate the feedback resistor, and make one of the resistors connected to the "+" input (R16 in the final drawing -- post #93) a variable one, to dial in the desired temperature. It doesn't get much simplier than that.
 
Last edited:

johnathon007

New Member
i bookmarking that page but i think im going to look for a prebuild thermostat just becuase im trying to keep this very professional looking, im not sure why i want it to look so nice but thats how i like to do everything.
 

BrownOut

Banned
Ir you use a simple mercury switch t-stat, you have to mount it exactly as it would be used in house. It's proper operation depends on the way it's mounted. If you use a digital one, you can mount it any way you please.
 
Last edited:
Status
Not open for further replies.

EE World Online Articles

Loading
Top