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# is it possible to boil water from room temp (20C) using regular batteries? Answered

Hello everyone,

is it possible to boil water from room temp (20C) using regular batteries?

according to my research, to warm up 500mL of water by 10C within 10 minutes, it will take 1 battery (3.7V 3400mAh).
I have a feeling that's wrong but I used this formula and some others:
[500 grams * (Tfinal - Tinitial) * 4.186 J/g C ] / [E.battery]

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You used exactly the right formula. The battery's capacity is in (rather weird :-) units of charge: ampere = coulomb/second, so mAh = 3.6 C. Energy is voltage × charge, so your battery has a total energy storage of 3.7 × 3.6 = 13.32 J.

500 mL of water is half a kilogram, so you need 2.1 kilojoules per degree. You're going to need a whole lot of little batteries to make your tea. Or you can get a car battery (40 Ah at 12V, 1.73 megajoules).

i got the kj it takes to boil water
how do i find the kj each battery has if i have the voltage and the capacity (mAh) given?
this way it will answer my initial question of how many batteries would be needed depending on the battery i use

[Weight] x [Delta T] x [Heat Capacity] will give you the required energy to heat it (divide by time to get power) but this will only heat it to 100°C, once there you need additional energy to actually change the state of the water. This is the Latent Heat of Vaporisation (for water approximately 2000J/g).
I won't go through the numbers for you right now but with these you can calculate how much energy you need to evaporate your water. Compare that to what you can get from your power supply :)

I did what you said as mentioned in my question:
E = [500 grams * (80 C) * 4.186 J/g C ] = 167440.0 so that is for the energy to heat the water.

I just want to heat it up and leave it, like say for tea.

my main question is, what battery capacity and voltage would be best to use to heat up water by 10C and by 80C, how do you calculate that?

Subject the water to a vacuum and you can boil water at room temp, about equal to 10,000 feet above sea level.