For the 3.7 V Li-ion batteries on test here I decided that, as the battery according to Canon should give about 300 pictures, I would apply the load in around 300 short intervals. That ideally translated to a 5.2 ohm resistor giving around 500 mA load for 16 seconds each. Settled for a more standard resistor of 5.6 ohm. The load in this case is around 2.5 watts so use an appropriate resistor – with higher rating unless you want it to get very hot! :-) I also decided to let the battery “catch its breath” for 16 seconds between each “picture” – again mimicking (very oversimplified) the real world behaviour while keeping the time down. Initially I wanted to follow a “real” standard like the CIPA one – but it was much to complicated for me and would involve far too much manual work. More to read about battery measurement in the CIPA document – but be warned it is very technical!