Good prospect for 2xIMR -- 6V 20W 150hr G4

[Tirodani]

I've been emailing with someone at Reflectalite for the past few days. They've been offering a 6v, 20W MR-11 bulb, and I asked about the lamp life design spec -- he said 150 hours, which is potentially good territory for a couple of larger IMR cells that have been flashing 50 and 100 hr lamps.

I also asked if he could supply regular non-reflectorized G4 bulbs to the same spec -- I got a reply back today saying that they could, and he would have some made. They'll apparently be on www.bikeco.co.uk within a day or so.

The downside, if there is one, is that the envelope size for the bulb used in MR-11's is usually T-3 1/4, I think, so it's probably a little large for a P60 head. Shoot. Tempted to buy a bi-pin adaptor anyway and enlarge the opening, since I've got this FM 2C body that's been sitting around unused due to the absence of the AW protected C's.

I won't be able to experiment for a few weeks at least, but I wanted to let y'all know about it. AW's 26500 IMRs should be out real soon, so break out your 2C mags and have at it.

 

[Timson]

I was just looking at these on Reflectalite's site... The G4 Bi-Pin GH102 (6v, 3.3A - 20W - 450 Lumen).

Could be a nice bulb - especially on 2 x IMR Li-Ions.


Tim.

 

[mdocod]

Now if we can get someone to make a T2.25, G4, 6V, ~75-100hr, 10A, (60W), ~1500L ... Should run well over 2000 bulb lumen on a pair of IMR18650 or larger

 

[fivemega]

Now if we can get someone to make a T2.25, G4, 6V, ~75-100hr, 10A, (60W), ~1500L ... Should run well over 2000 bulb lumen on a pair of IMR18650 or larger

Such a bulb won't last long when run continuously.
Most of incan guys at CPF push the bulb close to 3500K
At this kind of fillament temperature with that huge fillament size will melt the glass when runs continuously and there would not be any guarantee for bulb life.
I have already tried to cuctom make similar animal but manufaturer engineer explained me above statements.
BTW, instead of T2.25, G4, 6V, ~75-100hr, 10A, (60W), ~1500L bulb, you can design T2.25, G4, 7.8V, 10hr, 7.7A, (60W), 1500L+
Assuming voltage at bulb pins would be 7.8 or whatever it is under that load.
This way you can controll all specification easier and more accurate.
Maximum practical and reasonable life for T2.25 is about 45Watt.
You can go little more if you plan to run only couple of minutes at a time.

 

[mdocod]

Thank you FiveMega for that insight. Helps fill in a number of blanks about bulb design for me...

Makes me wonder, your 1794, which, I totally underestimated upon release, is probably on the absolute brink of possible bulb design for size/watt ratio eh?

 

[ANDREAS FERRARI]

Now if we can get someone to make a T2.25, G4, 6V, ~75-100hr, 10A, (60W), ~1500L ... Should run well over 2000 bulb lumen on a pair of IMR18650 or larger

If this won't work because of the small envelope melting then what about T3 or larger?.I'm only suggesting this because I like the idea of a 2xC IMR light @ 2000-2500lm.

 

[fivemega]

Makes me wonder, your 1794, which, I totally underestimated upon release, is probably on the absolute brink of possible bulb design for size/watt ratio eh?

That's right. For best output 1794 is at edge and for tactical reliability, P91 is at maximum possible point.

If this won't work because of the small envelope melting then what about T3 or larger?.I'm only suggesting this because I like the idea of a 2xC IMR light @ 2000-2500lm.

As long as you use the T3 or T4 bulb in larger reflector, it is absolutely doable and logical but for smaller reflector like 26mm diameter, bulb opening of 13mm is just wasting large part of reflectable surface.
Also need to mention that most of small reflectors are deep designed for larger reflective surface and in this case focal point is closer to inner side and enlarging bulb opening will cause part of light not being reflected. In this case, 65% ratio of total lumens out the front to total lumens produced by bulb will be like 55% or so.