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I'm thinking of purchasing a Koolatron P20 compact cooler and this ExpertPower 12200 battery

  • How long will cooler last with this battery at full charge?
  • Is this the correct battery to use for this?
  • Will it cool room-temperature products? For example, warm beverages? We don't have electricity, so anything that I put in the cooler will be warm.
  • Can the battery be charged with a regular AC plug? What would I need for this? Our office has electricity, so I can charge it there.
  • Can it charge other devices?
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Despite advertising "low power draw," the power is not available in any materials I can find, but the current is given as "approximately 4.5 amps." The technology used is thermoelectric refrigeration (or Peltier cooling) meaning that the unit is essentially always drawing 4.5 amps, not cycling on and off like a traditional refrigerator.

The battery you linked has a capacity of 20Ah -- or 20 amps x hours. This means it can supply 20 amps for one hour, 10 amps for 2 hours, etc (though the actual relationship isn't perfectly linear, depending on the current draw and ambient temperature, among other factors). In the case of the cooler, this means the battery could power it for 20Ah / 4.5A = 4.44 hours.

However, fully discharging the battery reduces it's useful life -- discharging to 30% or less is a common guideline. This would give you about an hour and 20 minutes of use.

If you are planning to use the cooler in a situation where you will not have continuous power supply, I would recommend buying a larger, "deep cycle" battery. This will enable you to use more of the battery's capacity -- up to 70% in many cases.

For example, this deep cycle battery (Amazon link) has a capacity of 35Ah. At 4.5A, you could run the cooler for nearly 5.5 hours before 70% of the charge is used up. While it costs $25 more, it will work better and last longer.

  • Thanks so much for the explanation. What do you mean by "70% depth of discharge"? Do you mean that running 5.5 hours will use 70% of the battery? – rbhat Oct 13 '17 at 21:34
  • @rbhat, that's correct -- I clarified in the answer. – LShaver Oct 14 '17 at 19:34
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    Discharging a lead-acid battery past 50% will dramatically reduce its lifespan. I recommend using 50% DoD instead of 70% for any calculations. – Jean-Paul Calderone Oct 14 '17 at 23:47
  • @rbhat if you feel this successfully answered your question I'd appreciate a click on "accept answer" right there under the voting arrows. Thanks! – LShaver Sep 18 at 14:40
  • Sorry about that. – rbhat Sep 18 at 18:16

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