I think it’s time for BLF community to make our own
(buck) driver design that will be more efficient than linear 7135 based drivers. Most of serious users are by now familiar with soldering iron and have AVR programmer so this should be a decent base for further diy projects.
The change from 25C to 85C represents a more realistic approach to binning. Having said that… Crap, crap, double crap. I still haven’t finished my previous XML mods.
Love it! having no current spreaders will look nicer in aspheric.Cree is notorious for releasing higher bins later down the road,so I might wait for the better binned stuff to surface.Other companies are really floundering wirh their new stuff,especially SSC with their z series...fail.I'd like a few to play around with,even if they are lower bin first thing I would do is throw some in my outside security light.
i think it’s 20% more from about 20% efficiency —> 5% more energy into light
since every new generation of cree leds seems to have a lower Uf this could be an interesting idea.
I’m going to read up on buck converters, i never liked the idea of burning off excess voltage in linear regulators.
Been lazy about ordering a U3 on copper to pop in my HD2010, and it pays off!
Will be looking for the XML2 in high bin on copper now! Direct drive off a freshly charged king kong with a big jump in surface brightness, this should throw nicely.
Is this a “real-world’ 20% increase in light output with an optimized reflector and driver? Or will it be realistically more or less?
For example, with the correct driver, let’s say a Fancy Fandy hoo-fire ke-hd-2010-5-897 now puts out 875 lumens with a T6. With an optimized driver and reflector, the comparable light with an xm-l2 will now put out 1050 lumens?
Where do you see lower Vf?
Maybe I’m wrong, but when I calculate with the old xm-l’s “temperature coefficient of voltage” which is –2.1mV/°C , I get 3.224V Vf at 3A and 85°C.
3.35V + (–2.1mV/°C * 60°C)= 3.224V
this value for the new xm-l2 is 3.35V
And because of the lower “temperature coefficient of voltage” of the new xm-l2, which is –1.6mV/°C, higher core temp means automatically higher Vf.