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I'm planning on using this unit: 12V Peltier water cooler

for a portable heater/cooler. As such, I would need to run it off a battery. Based on what I've been reading, the best choice is a deep-cycle battery. Problem is, these are quite bulky and heavy for my application.

My questions are:

  1. Is there a more efficient way to run a peltier module off a battery?

  2. Given this module is 180W, I plan on running it off a 12V supply, this gives a 15A draw. If I was to plug it to a 4AH battery, would that mean the system would only run for about 20 min or would it damage the battery?

  3. What kind of safety margin should I apply when trying to size the battery? E.g. 10%?

Thanks in advance for your help.

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  • \$\begingroup\$ 'Efficient' and 'Peltier' do not occur in the same dictionary. Use a compressor type, you'll get 5 times the battery life for the same cooling power. \$\endgroup\$ – Neil_UK Jan 29 '18 at 14:56
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    \$\begingroup\$ Even 20 minutes is ambitious, you'd be lucky to get ten at that rate. \$\endgroup\$ – Finbarr Jan 29 '18 at 15:10
  • \$\begingroup\$ Water cooler... yeah. About that. How much water do you want to cool, and by how many degrees, and how fast? Put these together with the heat capacity of water and determine the cooling power you need. Double that to get the pumping power (check the Peltier datasheet). If you want a more efficient way, look at 12V compressor coolers. \$\endgroup\$ – Brian Drummond Jan 29 '18 at 15:12
  • \$\begingroup\$ @Neil_UK Thanks, my restrictions are size, weight and noise. Which is why I ruled out compressors, do you have any recommendations? \$\endgroup\$ – John S Jan 29 '18 at 15:46
  • \$\begingroup\$ fwiw, there's no way i believe those dinky wires on the thing can handle 15 amps. not even close. that would really tax most ATX PSUs as well. 180W likely refers to the continuous cooling rate; how much heat it can move away from the faceplate; the energy used for that is probably no more than a few amps. \$\endgroup\$ – dandavis Jan 30 '18 at 6:23

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