You'd really need to know the Peukert factor to properly know the life of the battery. Likely easiest to test in a freezer unless your engineering students are looking for a neat finite-element-analysis (FEA) project with a computer simulation.Ĥ) What battery type? If a LiOn battery, its going to be pretty close to the W-hr rating if published. You could likely make an educated guess based on the insulation (say 1/2" of styrofoam) but the container design matters too, the lid might loose 3x the heat the rest of the unit looses because of how its attached.
BATTERY OPERATED HEATER FULL
Some of the newer NiMH or LiOn batteries could come close to meeting the full power because they are designed to discharge quickly and not suffer the penalty.ģ) You need to know the heat transfer characteristics of the storage unit. But this is the total over 20 hours, if you use it for only an hour you'll only get 1/3 of that or less because most batteries like to be discharged slowly, not fast. It might be 30%, but it could be as bad as 10% even during the peak time of noon-3pm.ġ) Close enough to begin testing, but you need to know the conditions of the calculations - batteries loose power when really cold too (but they heat up as you use them and will offset this a little)Ģ) How big of a battery? Like an AA cell or a D cell? Batteries are rated by ampere-hour (Ah or by a 1/1000 unit of mAh) and you could multiply by the voltage to get W-hr or for a AA cell of 2000mAh * 1.5V = 3 W-hr which would seem to be 3W for one hour. The other half of sunlight is where the solar cell functions, and that light is similarily not very effective either. At a northern latitude where cold conditions occur, they occur because the sunlight is not very effective at heating the ground. Unless on a mountain top, being near the equator generally isn't where you find freezing temps. Second, solar cells are rated at perfect conditions. You could always over size the heating portion of the device and regulate it back to maintain the temperature too, and while a much better solution it would be more involved. So if you could make a freezer go to 0 you could put a thermometer inside the unit and check to make sure the wattage you believe will work will maintain the temperature. I'll come back to solar in a bit.įirst, you should establish the heat insulation/transfer value of the storage unit and find the power requirements to maintain the temperature difference. Ok, your current from solar cells is pretty high but regardless the wattage is within reason and that's all that matters. How can I figure out the life of a battery when used in this situation?Īny help would be greatly appreciated, if you need any more information please let me know. If it is possible, how can I calculate the power requirements to keep this warm at the minimum temperature?Ĥ. Is this a possibility, or is the power required too great for a battery to produce?ģ. I have the following questions regarding this project.Ģ. I also need a way to keep these heated when the sun is not out so that is why I decided to include a battery.
BATTERY OPERATED HEATER SERIES
My initial thought is to use a series of resisters to produce heat. What I am trying to figure out, is the best way to produce heat using these solar cells. Using this formula, I figured that the typical cell outputs 2 to 2.5 watts. I understand that you can figure out the wattage by multiplying volts by amperes. 03 watts.įrom what I have found in my research, a typical solar cell produces. Using this formula, I calculate that the average power to run a square inch of blanket was. One of the electrical engineering professors on campus told me that one way to calculate the wattage necessary to run a heater of this type was to look at the dimensions of an electric blanket, and divide the number of watts needed to power the blanket by the area of the blanket. I believe that this can be done using a low voltage heater similar to an electric blanket.
This is insulated, have a volume of around 1200 inches, and is powered by the sun and a battery when necessary. I am attempting to design a product that stays warm, 50 degrees when the temperature outside is 0 or more. Hi, I'm a business student working on a business concept, and I need some help with an electrical problem.
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