I couldn't justify spending $50 to have a styrofoam sphere shipped to me to measure these lights. The local WallMart does not stock the 'Big Bobber' cooler, which at $22, I could justify as it would be usable for its original purpose. The DIY Integrated Sphere thread indicated that some used non-spherical enclosures but that beam-shape issues might distort results.
So I opted for $1 small strofoam cooler. I mean the DX meter is no super accurate device, and we are looking for rough comparison numbers here, not precision.
The container is a little too thin and the inner surface not as reflective as one might like, so there is some light leakage. On the 20000 scale the meter showed 000 but on the finest scale of 200, it was picking up 2 from ambient (room light off) sunlight.
Results (these are the readings on the meter in the 20,000 range so all values are 100 X larger than reported, the headlamps were measured on the 200,000 range as 155, or 1550 on the 20,000 range, so actual readings were 100 x higher as well):
Lower lux figures than Erwin'd Lux readings, but expectedly so with the cruder integrator. Both sets of NiMH freshly recharged. Different brands and different amounts of use/abuse (near complete discharges). I did not swap battery pairs in these, from Erwin's low battery readings, we know they are highly sensitive to amount of charge. Fairly rapid decline when on full on mode (8-10% in 10 minutes). Some of this may be heat related, but most I suspect is battery darinage rate. Unless you plan a short ride or swapping out the batteries every 30 minutes or more often, I suggest flash mode.
One Radbot1000 was used with its original batteries about 4 hours, the other had the orignal batteries set aside for the test. Again, about a 10% loss in lux with 10 minutes of running. These were swapped between the lights. Light differences swamped by battery charge condition. About 2 X as much light as PBSF's which figures for a 1 watt versus 1/2 watt LED assuming both are run a similar amount below their rating.
The 1 watt red spots put out over 20% of the light of the Triple XPG-R5's run at 0.5 W (4.65 W), so the reflector/glass and the 1 Watt Red Led's appear to be quite efficient. Or, much more likely, running at about 1.5 W as some users ahve reported. I was pleasantly surprised to find the 10417 + cover was the same as the Aspheric lenses with tubes and cover. The two headlamps were at room temp 25 C, at half power, and runs too briefly to heat up. The lens and cover losses are guessed to be 20%.
At 0.5 A, an XPG-R5 puts out 1.4 X its 139 lumen rating for 350 mA, factoring in the 20% loss to lenses, three should put out 467 lumens @ 0.5 A. This provides a crude conversion from the lux readings to lumens (1550/467 = 3.31). The results are in this last table.
The SBSF readings are close to Erwin's and since batteries are SO critical, we can't quibble over the difference. So it looks like the crude IS and conversion are providing decent numbers for comparison to Erwin's.
The Radbot1000's do seem to put out about twice the light of the PBSF but on full-on mode they eat power from the double AAA's rapidly. Flash mode recommended or an extermal battery pack. I wonder how much overvoltage they'd take (single Li-ion)?
The Marwi-Dx Spots produce 3-4 X as much light as the Radbot1000, and 7-8 X the PBSF's.
So now you have numbers to back up the solar fare pictures of post 102. Enjoy! Sunny today: Daylight shots coming.
Must not be a pleasure to drive close behind you. The Dx spotlights in the Marwi lights will lack side visibility, but I understand you intend to fill that up with the radbots.
