Define high loads... For me I just use 3 one watt lights, I wear, for a typical 10 hour work day. About 1 watt headlamp + .5 watt on wrist for each helper. (Though the process may be evolving.) I would like to push 3 watts per headlight, but battery technology isn't there--I would need 30 watt hour to get one workday, or spend half day popping in batteries and testing cells.
Also, you need to be more clear about branding. I found Duracell 2650 much reliable than any other brand (kodak worst, then energizer). Also, I take wrappers off for better heat transfer (beware, on some lights you need that vinyl insulation) and put ice pack on cells when quick 15 minute charging, so they are cool. Since doing this a few months ago, I haven't lost a cell to higher resistance--the more contact with ice pack, the better. I've yet to invest in a more expensive slow charger, and know this will horrify some users here. I find charging on cheaper slow chargers seem to ruin my rechargeables for some reason.
Even Eneloops have first few hour off charger drop in capacity. I know a 2900 Maha isn't 2900 after a few hours, but assume at 1 watt to 1.5 watts, the ratio is similar to package rating 2000/2900. I sure see a difference between runtime with 2650's and 2000's of a few hours, but yet to try Eneloops but have my share of the Rayovac Hybrids.
