Originally Posted by
Skones MickLoud
Lumens can't convert to wattage, as they measure completely different things.
Well... no, they are not completely different things. The lumen is a measure of light energy flux*, and watt here refers to electrical energy flux. Electrical watts going in, multiplied by an efficiency coefficient (always < 1) equals light energy out. Different lighting technologies have different ranges of efficiencies, so it is possible to say, for example, that "A white LED typically produces between 20-60 lumens per watt input of electrical energy." See
http://www.mge.com/home/appliances/l...comparison.htm
*This is not exactly true - the lumen is color weighted for human vision perception - but it's close enough to true for this argument about light-producing devices for human vision enhancement.
Here's another approach. Capacity / runtime = amps. Amps x volts = watts. What's the claimed runtime? What's the battery pack made of? Example: 2.5 Ah battery / 2.5 hours runtime = 1 amp. 2.4 volts x 1 amp = 2.4 watts.