Doh!Nut
Newly Enlightened
I am making a dive light and am having trouble deciding which is the most appropriate emitters to use.
The Major design requirements are.
***Spot Beam
***15 watts power consumption (to achieve run time from 14.4v Li-Ion battery)
***59mm internal diameter of casing
***All reflectors must be supported from below (The battery is attatched to the removable endcap of the light, the LED and optics must sit ontop of this, the cylindrical housing and lens slides over the reflectos and battery and screws onto the end cap.
I have a 26v Shark if I want a boost driver.
I have a 1400ma Konlux buck driver. (also a couple of 1000ma buckpuck/KonLux etc.)
My original Plan was to use the shark driver with seven Cree Q5 with fraen lenses (running at reduced current to fulfill battery life), the LED are available at a reasonable price $45 for seven. The reflectors are a bit more problematic shipping to the UK and I would probably have to use the small parcel forwarding service for these, budget $30. On the upside, each LED gets its own reflector designed for the purpose but there would be a query over how much throw a 15mm deep reflector can generate.
However I have three metal 35mm reflectors that could be trimmed (a lot) to fit inside the housing (59mm diameter) These reflectors are known to have very good throw with a single CREE, but three (single die) LED would not produce enough light. The reflectors could be modified for use with a P7 Led (the reflectors have a flat base which could be easily opened out to accomodate the P7), The Vf and the 1400ma driver combine to get the power spot on, but would they still give a good beam in the XR-E reflector?
Price would be $70 ie cost about equal.
Both the 7Cree and the 3SSc-P7 solutions would provide good lights, they would give alot of light and with different drivers/battery life could produce even more
The Maths
15Watt to LED (I have a little leeway on battery life so will ignore driver efficiency)
P7
Three P7 in series =Vf 11.1v Using 1400ma switching regulator = 15.5Watt
A C-Bin P7 gives 400+ Lumen at 1400ma - Total 1200 Lumen.
Q5
Seven Q5 in Series = Vf 24v using a shark set to 650ma (according to evans testing) 24v*650ma = 15.6W
a Q5 gives 175 Lumen at 650ma - Total 1225 Lumen
So according to the information I have the different reflectors give the same output and efficiency which leaves the quality of the spot beam and the mechanical strength of the reflectors mounted on top of the LED.
As an aside the peak output for each is
P7 3.7v*2.8a *3 = 31watt = 2400 Lumen
Q5 3.5v*1.0a *7 = 24.5Watt = 1650Lumen
which kind of makes sense if you think of each P7 as having four dies then we are comparing 12dies with 7 dies.
So, which one should I choose?
The Major design requirements are.
***Spot Beam
***15 watts power consumption (to achieve run time from 14.4v Li-Ion battery)
***59mm internal diameter of casing
***All reflectors must be supported from below (The battery is attatched to the removable endcap of the light, the LED and optics must sit ontop of this, the cylindrical housing and lens slides over the reflectos and battery and screws onto the end cap.
I have a 26v Shark if I want a boost driver.
I have a 1400ma Konlux buck driver. (also a couple of 1000ma buckpuck/KonLux etc.)
My original Plan was to use the shark driver with seven Cree Q5 with fraen lenses (running at reduced current to fulfill battery life), the LED are available at a reasonable price $45 for seven. The reflectors are a bit more problematic shipping to the UK and I would probably have to use the small parcel forwarding service for these, budget $30. On the upside, each LED gets its own reflector designed for the purpose but there would be a query over how much throw a 15mm deep reflector can generate.
However I have three metal 35mm reflectors that could be trimmed (a lot) to fit inside the housing (59mm diameter) These reflectors are known to have very good throw with a single CREE, but three (single die) LED would not produce enough light. The reflectors could be modified for use with a P7 Led (the reflectors have a flat base which could be easily opened out to accomodate the P7), The Vf and the 1400ma driver combine to get the power spot on, but would they still give a good beam in the XR-E reflector?
Price would be $70 ie cost about equal.
Both the 7Cree and the 3SSc-P7 solutions would provide good lights, they would give alot of light and with different drivers/battery life could produce even more
The Maths
15Watt to LED (I have a little leeway on battery life so will ignore driver efficiency)
P7
Three P7 in series =Vf 11.1v Using 1400ma switching regulator = 15.5Watt
A C-Bin P7 gives 400+ Lumen at 1400ma - Total 1200 Lumen.
Q5
Seven Q5 in Series = Vf 24v using a shark set to 650ma (according to evans testing) 24v*650ma = 15.6W
a Q5 gives 175 Lumen at 650ma - Total 1225 Lumen
So according to the information I have the different reflectors give the same output and efficiency which leaves the quality of the spot beam and the mechanical strength of the reflectors mounted on top of the LED.
As an aside the peak output for each is
P7 3.7v*2.8a *3 = 31watt = 2400 Lumen
Q5 3.5v*1.0a *7 = 24.5Watt = 1650Lumen
which kind of makes sense if you think of each P7 as having four dies then we are comparing 12dies with 7 dies.
So, which one should I choose?