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I have set up a peltier module with an aluminium heat sink, cooling fan, 12v, 7ah battery supply and thermal paste for the purpose of cooling water. At first, it performed well. It dropped down to 3.5°c in 2 hours. However, after the 2 hour mark, it had suddenly started increasing in temperature. I didn't move it or change the room temperature at all. I decided to change the cooling fan to a liquid coolant, which didn't work either. I bought another set up, but this time I noticed the peltier module and cooling fan would only perform seperately when tied to the battery unlike before when both performed well even when the wires were tied together. So I brought back the previous set up, and tested it with the battery again. The same problem occurred. Can anyone explain why this is happening and what I should do to get it to perform again?enter image description here

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    $\begingroup$ please furnish a schematic diagram including all wiring and I'll have a go at it. $\endgroup$ Mar 29 at 17:12
  • $\begingroup$ Sorry for the rough diagram, but that's essentially how I set it up. $\endgroup$
    – Siva
    Mar 29 at 18:31
  • $\begingroup$ A peltier will only produce a temperature difference of x between one side and the other, if ambient T is fixed then x defines the T of the other side. $\endgroup$
    – Solar Mike
    Mar 29 at 18:42
  • $\begingroup$ does the battery still have power after 2 hours? If it pulls 75 watts, that would be about 2 hours. $\endgroup$
    – Tiger Guy
    Mar 29 at 21:40
  • $\begingroup$ Please define "perform" - How do you verify there's a delta - T at the Peltier junction? (remember that if the "cold side" stays warm, the "hot side" will get hot if the junction is functioning. ) $\endgroup$ Mar 30 at 11:34
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It is possible that there is a short circuit somewhere between the heat sink, the peltier slab, and the fan housing. Heat sink grease is electrically nonconductive but if a direct path gets formed through it then the device would stop working. I suggest you take the entire thing apart, clean it up, and test the fan by itself, the fan with the heatsink, the peltier slab by itself, and the slab with contact with the heat sink.

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  • $\begingroup$ Thank you for the suggestion. I tested the slab and fan seperately, and they're both working by themselves. I then attatched the slab to the heat sink, and it also seems to be working. Similarly, the fan also worked with the heat sink. However, when I set the whole equipment up again, and attatched both the fan and slab's wires to the battery, the same problem occurred in which the fan stopped working. $\endgroup$
    – Siva
    Mar 30 at 8:18

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