Energy storage density

Some people have mentioned using an electric cooktop or electric frypan/toaster oven etc while camping.

Be aware that these consume a LOT of power & are thus of limited value when you are not plugged in.

A microwave oven isn't too too bad when you aren't plugged in because almost all of the energy used goes directly into heating the food.

About the only really efficient electric food heaters are immersion coils; even then the battery weight required to store the energy is huge compared to the equivalent energy in gas.

The amount of energy stored in a gallon of petroleum fuel is huge; that's one of the principal reasons to consider things like coleman stoves, lanterns, catalytic heaters, etc.

To be precise about it, two interstate golf cart batteries weigh 126 lbs and store 225 amp-hrs @ 12 volts or about 2700 watts-hrs; this is an energy density of 21 watt-hrs/lb.

The energy released by burning a pound of propane is 6387 watt-hrs/lb.

So one lb of propane stores 300 times more energy than one pound of batteries. That's why one should consider using it for energy intensive applications like heating.

Another interesting fact is that a dual mantle coleman lantern emits about 2600 BTU/hr in the form of heat; that's about the same as a 750 watt electric heater.

dmartin@newarts.com 2004 08 02