With the recent outrageous claims on his new multiple-hundred lumens LED flashlight JG re-sparked my interest in his 673 lumens claim for the M3 using the high-output bulb.
I think I pretty much nailed it now.
His claims had been for a measured 673 lumens at 9V and somewhere else he mentioned a 3.1 current draw.
My measurements show the actual bulb in the M3 to draw ~ 2.7A when used with 2 18500 LiIon cells and dropping the cells voltage to ~ 6.8V and when used with 3 123 cells (the standard config of the Goncz M3) it draws 2.5A and drops the cells voltage to ~ 5.8V.
All these data points suggests or confirm that the bulb used is the WA 01274 which has a design voltage of 7.2V and draws 2.77A there and is speced to produce some 553 lumens then.
Now taken as a given that JG really measured the bulb in one of his lights using a bench supply to get the claimed 9V supply voltage and that the 673 lu are accurate one could calculate that using the actual 3 123 cells and taken the relation between measured flashlight output at 9V (overdriven by 25% it would theoretically give you a 220% brightness increase - while underdriving it by 20% as in the case of 3 123 cells gives you a meager 46% - in the case of the 2 LiIons its minus 5% voltage and 83% brightness) which would be a theoretical bulb oputput of 1216 lu vs measured 673 lu which is probably OK taking all relevant losses into account one would arrive at a theoretical measurement of probably around 140 lumens which would fit the results seen by people using the M3 that it compares against the 105/120 lumens Surefire lights while beeing drastically yellower in output - obviously a result of heavily underdriving the bulb.
My recent reports that using 2 1400ma 18500 LiIons had been very much improving the results is now also much clearer - at only 5% underdriving and 83% brightness one calculates 255 lumens and comparing it against a P91 driven Surefire its coparable while still being yellower and having a worse beam, but we´re getting there now with those Li-Ions.
To explain my calculation:
Stock WA 01274 at 7.2V gives 553 lumens
Overdriven by 25% (9V) gives a theoretical 1216 lu and JG claimed 673 lu - which is ~ 1,8 I will use as a corection factor. This is a quite typical loss starting from the single bulb output until the beam gets out of the flashlight lense.
Calculation the underdrive using 3 x 123 or 2 x LiIon this gives us:
WA 01274 at 5.8V using 3 123 is minus 20% voltage at 46 % brightness so 553 lu x 46% / 1.8 ~ 140 lu
WA 01274 at 6.8V using 2 LiIons is minus 5% voltage at 83% brightness so 553 lu x 83% / 1.8 ~ 255 lu
I think this mix of measurements and theoretical math gives pretty accurate results which do conform pretty well with real world testing and reports and would results in some factual statements regarding the Goncz M3.
The Goncz M3 primarily lacks a fitting joice of bulbs resulting in way underdriven inefficient output and the reported much too yellow beam.
The Goncz M3 could be easily improved by either the use of 2 high-cap LiIon cells or the use of a properly selected bulb
The Carley Bi-Pin to PR base socket specified at 1A is used well over his design specs at ~ 2.7A in the Goncz M3
John Goncz reported claims of the M3s 673 lu might be true for bench-supply testing of the light and bulb combo but nowhere are indicative of real-world performance of his flashlight.
John Goncz seem to be unable to understand the concept of voltage drop when cells are used with high loads which question the credibility of his multi-million dollar engineering efforts.
It is a shame that a flashlight with some unquestioned nice new design ideas and which has been tested and some shortcomings reported doesn´t get improved upon easily to be fixed issues but the manufacturer starts to behave unprofessionally to the highest degree.
I really ask myself why I don´t leave the guy alone - at this rate of multi-million design efforts and corresponding results this post would be well worth a couple of billions
and I probably won´t get anything besides further insults from the guy
But Mr. Goncz - just take it as my christmas present to you - and for all other readers - my very early sentence about taking care not to be "Gonczed off" your money is well prooven by this I would say.
Klaus
BTW - I would still appreciate receiving the paid for replacement bulb and the paid for and as advertised borofloat lense
), you will loose more light. also remember that the light isn't bouncing off the surface only once, some of the light bounces from wall to wall to wall.
