Simulated Brightness & Output Runtime - AA & Ultra

In the absence of a legitimate runtime comparison between the Arc AA and the CMG Infinity Ultra, I decided to make one up. I took Roy's runtime curves for the 2 lights and adjusted the scales to match my field measurements of total output and hotspot brightness.

First, the total output plots:



The Arc is brighter through almost all of the burn time. Around the 11th hour the CMG's better regulation allows it to match the Arc momentarily. The Arc has a superior corona; this is probably due to the reflector.

Now for hotspot brightness:



The Arc starts off brighter. Around hour 4 the CMG's regulation puts it into the lead. After hour 11 the Arc takes back the lead as the CMG falls out of regulation.

These differences are probably more academic than of issue in real use. Even side-by-side the two lights have very similar output and usefulness.

I publish these charts mostly to make up for conclusions I posted earlier based on various bits of information gathered from CPF. At the time it looked like the Arc's circuit was as much as 60% more efficient than CMG's. My more recent observations indicate that the difference attributable to the circuit is more like 5% - 15% with a little additional total output difference due to the Arc's reflector.

Not as much difference as reported by some, but more consistent with typical circuit design differences. I'm still on honeymoon with the Arc AA. What a great light!

I don't think it's worth obsessing over the brightness of a 5mm LED light. If brightness is important, get an LS. Right now I'm using an Infinity Classic and it's bright enough for most anything I might use an Ultra or Arc AA/AAA for. It's about as bright as my Arc AAA because the AAA's battery has several hours use. With a new battery, the AAA would be about 2x brighter, but I haven't felt the need for it and the old battery has plenty of life left. I do have some spare batteries in the same bag where the AAA is, of course.

The charts are mostly an academic exercise, as I mentioned, but the output difference between a regular Infinity and these overdriven lights is more like 5 times. An overdriven about to fall out of regulation is still about 2x as bright as a regular on fresh batts. I've found the difference significant in mixed light situations. Run one of the brighter lights, such as an Ultra or the Arc AA on lithium, and you enjoy the 5x brightness difference for most of the battery life. It would be great if Roy could do one of his runtime tests for the Arc AA on lithium.

yeah Roy!

interesting chart Dave.

The top chart confirms my observations...kind of a nice feeling.

The bottom chart was sort of surprising in that the Ultra appears to have a brighter hotspot for more overall time than tha AA....7 hours to 4.5 hours

I have not yet tried lithium in my AA

I haven't tried an Ultra on a lithium, but I just compared an Arc AAA with a new Duracell alkaline with a regular Infinity with an almost-new Panasonic heavy duty cell (not even alkaline). I'd say the difference is about 2x, nowhere near 5x.