Originally Posted by
Richard Cranium
I doubt that there is any way to determine the power consumption of lights in blinking mode. There are a number of reason why, including the circuit efficiency itself.
Of course there is -- measure it.
Considering that the circuit goes on and off quite quickly, a multimeter won't work well in many cases, but you could charge a battery, then discharge it and measure it's capacity (how to do this is left as an exercise for the reader, though it's not difficult) -- then charge it again and see how long it would power the light until it reaches your chosen cutoff voltage and calculate the power used -- this would be pretty accurate.
The whole "charger" total mA measuring is bogus. The display only reflects the current drawn into a tube of electro-chemical paste - not an actual expression of power consumption - as in light.
It sounds like he's trying to calculate how much it costs to use the light -- so measuring the power used by the charger is exactly the right thing to do. (But measuring how much power is put into the battery is wrong -- the charger is likely very inefficient if powered by 110v AC and charging small batteries. Instead, measure the power consumed by the charger. Perhaps with
one of these (though it'll cost more than many years worth of electricity to charge your lights!)
If you really want to be through, take the cost of your batteries, divide by the number of cycles they're likely to survive, and add that to the cost ...
The larger costs of of using these products lays with the energy consumed during manufacture and the chemical wastes associated with the technologies surrounding them. I would suspect using a generator could be an increase in efficiency - but that's a guess as well.
Possibly.