XHP70 brightness with diff size reflectors w/ pics

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Engine Guy
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XHP70 brightness with diff size reflectors w/ pics

I’ve modded a few lights with the XHP70.
One is the HD2010 which is my fav. and super bright, its got to be 5000+Lumens.
All the others are some kind of C8 variety.
My question:
Does the reflector of the HD2010 make that much a diff in the brightness?
In beamshots – the light on the left is a C8 mini with a 1 3/8” dia. reflector and its not very deep. (2nd from left in 2nd pic)
Both use direct divers.
I get about 6.25 amps at the tailswitch on both lights.
Now I’m new, so please explain to me, is it 6.25amps x (4.2V x 2 for the 2 18350s) 8.4 = 52.5W
that both lights (xhp70s) are driven at?
Meaning they should be similar lumens right?
And if I pull the reflectors out, both lights seam to have about the same brightness in their floody state.
Also the other 2 C8 lights I have with the XHP70 are about the same as the C8 mini in the pic, the DH2010 is just that much brighter.
Altho the pics exaggerate its brightness.
All use Quality IMRs. efest, windyfire, basin.
So the only difference I see as to why one is way brighter then the others would be the larger reflector.
Is this correct?

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Edited by: Engine Guy on 01/25/2017 - 00:48
Enderman
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“photo not found”

Engine Guy
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sorry it took me a few trys to get them to show up Facepalm

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Enderman
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thanks Smile

The Miller
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Cooling plays a role too, the C8 should make the LED warmer thus less bright

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Short answer : the bigger the reflector (both diamter and depth), the more intense the beam.
Large reflector : more kCd with same emitter/amperage.

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Engine Guy
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ok thanks, that’s what I thought it has to be… the reflector, but what a huge difference.
The C8 mini is great to have 3000-4000 lumen light that you can pocket,
but the HD2010 is just on anther level, I love it.
I was thinking of building a 3 or 4 x XHP70 flashlight, but now see that it would need some large reflectors
to be really impressive. If done with small reflectors it may not be any more impressive than the HD2010.
With large reflectors it would be huge / bulky, not sure if I want to do that.

Ok, so am I calculating watts correctly?
Tailcap amps x battery volts?

Also, When using direct drivers, where positive goes straight through to the LED, could you just NOT use a driver,
and have the positive (battery) go straight to LED and negative go thru tailswitch, resulting in a flashlight with full power,
as hard as the batteries push it, and no modes. I think this would be good for a multi LED light just for show.

thanks for the help guys

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Angler
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One thing to consider is that the switches are not equal.
The C8 may have more loss at the switch than the HD2010.

The proper way to determine the amperage of the light would be to measure
with a clamp on the positive wire going to the led.
This will account for and show you the losses through the switch.

Also you could check the resistance of the switches
for comparison purposes.

It’s difficult to tell the case from your beamshots, but maybe the C8 is making more spill
than the other light. I can see that the HD2010 has a smaller hotspot.
2 lights can make the same lumens but have very different beam profile due to reflector.

Lexel
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The intensity of a smaller hotspot is making a huge difference in brightness.

More light gets in the hotspot with a wider and deeper reflector, as well the hotspot gets smaller so the ontensity hoes up a lot