How to work out how powerful a rocket stove is. I can boil 2L water in 6mins.

My rocket stove/BBQ I can boil 2L of water at about 15deg celsius up to a violent boil in 6mins. From that information can you woek out how much power it has?

Will that then be in BTU's?

Ooh, a math problem.

Q = m*cp*deltaT

2L of water has a mass of 2 kg
15 degrees ac to oiling will make a deltaT of 85 degrees
cp for water is 4186 J/kgC

So Q = 2*4186*85 = 712 kJ = 676 BTU

of course this is over 6 minutes, so the power evolved by the RMH would be these numbers divided by 360 seconds. So approximately 2 kW of power.

These numbers are rough ballpark kind of numbers. Your water probably isn't pure water, so the density, specific heat, and boiling points will all be a little different. But still, your stove is putting out a fair bit of energy!