Hi guys,
What a great forum, informative posts with more objective opinions (rather than expense = quality) than some comparable sites.
I am particulary interested in bike-lighting and currently I am trying to "improve" my main-beam lighting which is using a 7b tint mce, and a 1c tint xml, both in P60 hosts wired to a thumb switch and an external nimh battery pack.
Cheers!
Welcome Bingo.
Hmm, What do you want to improve? It seems you have pretty much made your own homework so far. :)
At what current do you run the XM-L and MCE emitters in p60 hosts? I'm interested because currently all XM-L's i have gets scorching hot in 15min of use at max (2,9A-3,1A). I believe you drive them a bit conservatively or does the added airflow while moving help that much? I'm concerned about the output sag by heat over time.
I'm wanting to get a bit further throw from the xm-l, so I've ordered a manafont p60 drop-in but now realise it probably won't be much throwier than my homemade drop-in, so today I've ordered an Ultrafire C8 xml as well.
The airflow helps cooling a great deal. On my desk a host will get very hot in minutes but is cool to the touch when cycling. I use enough foil wrap that i have to lean hard on the host to force the reflector in the last few mm.
The LEDs are both driven hard at about 2.7amps by shining beam 8x7135 drivers. I feed them approximately 5volts from a 4xnimh battery pack, and any excess voltage will be converted into heat as well ....... but they will continue to draw 2.7amps untill the batteries are nearly exhausted. Cooling may be helped a bit by the host's battery compartment being empty.
I think that if your lights are getting hot to hold your are probably getting very good heat conduction away from the LED, and if you continue to hold it your hand will be a very good heatsink. (ymmv, no responsibility taken for any stupid advice, please consult your local doctor if an arm is burnt off, etc.)
Well, i notice i dramatic increase in throw from the SMO reflector (manafont dropin), futhermore i switched to a coated lens which should add some more throw. Other than that, you might really want to go on the C8 body and smo reflector... but judging from what i saw here on BLF it would not make a night and day difference. Perhaps you might want to try a triple Q5/R2 flashlight along with a nice diffused XM-L? A flood light and a long range one. That is most commonly wanted by cyclists.
For me a 1200mA driven R5 is enough. Urban / offroad 50/50 trekking. Have yet to try XM-L. In march/april perhaps when the temperature reaches above 16C...
I have to test my heatsinking with a thermometer and lux meter when they both arrive. I'm pretty sure i did a excellent job by carefully wrapping them in alu foil. Have to find ultrathin copper foil of roughly 2cm in scotch tape form.
Since your P60 hosts are empty, why dont you cram them with a slab of copper? Should be better than air... but then again aluminum might be better you don't really want to add weight on your bike don't you?
Btw, how's the runtime
Welcome to BLF, Bingo!
Are you already using a smooth reflector with your XM-L? If not it's worth a swap. I've tried the XM-L's with both smooth and OP reflectors, and there's quite a noticeable difference in throw between the two...more so than say an XP-G setup.
-Match
Thank you for the suggestions. I am using smooth reflectors at the moment but I think if I could get more throw from the xml then I would go back to a more floody op reflector for the mce, or possibly a diffuser for it. I find the warm tint of the mce is much more comfortable for the near bike flood and shows more realistic colors in the verges/hedges (also differentiates brown from asphalt better).
Runtime changes with the very rough battery packs I use. Battery holders from "maplins" that I use single or wired in parallel. At the moment I have 2x4 Lidl "tronic" C-size cells of 4000mah each. The batteries were only about £1 each and have done very good service. After a recent ride of 1 and 1/4 hours with 4 batteries feeding just the mce light the batteries registered "low" on the charger, but if the temperature is above zero celcius they would still have registered "medium" I think.
Last year I had 12x of these batteries in the same holders wired in series to an Osram ostar 35watt halogen bulb. Both the bulb and cheap battery holders coped very well with it.
Aloha and welcome to BLF Bingo!
Welcome to BLF, Bingo! I am also a new comer
I'm not much of a builder but see bike lights as almost an easier place to start than flashlights .
I have been reading http://forums.mtbr.com/forumdisplay.php?f=124 about reginias and have thought of building some simple lights for fun .
Welcome to the best forum in the world interested to see any and all pictures of what you have going on .. there are a bunch of closet engineers and electrical wizards hiding just waiting for someone to ask the right question. have fun here .
Aloha and welcome to you too Hayley!
Welcome to BLF, Bingo! I am also a new comer