I've forgotten...what is good for a P-60 drop-in?

[Tom_E]

You are too generous! I gave my wife one of those $2 AA zoomies from WallBuys. Of course it was mod'ed with a XM-L2 U2 1A on copper...

[DB_Custom (Dale)]

I am fairly impressed with this combination, not sure about the de-domed XM-L2 tint though. It’s not bad, but is headed towards green. In normal use it’s hard to distinguish, but compared to most of my other lights it’s obvious.
I used the Canon G1X, ISO 1600, f/5.6 for the 28mm, f/5.8 for the 112mm. Red oil drum is 97 yds.

[comfychair]

Will the choice of host really block light with the bezel, when the front opening of the reflector is only 20MM?

[DB_Custom (Dale)]

Comfy, I think that’s with the 26.5mm standard reflector in a P-60. Pretty sure this 20mm isn’t getting any light blocked by the host.

[Tom_E]

I can't find the thread, wonder if it was deleted, but a guy had all these measurements on a spreadsheet, showing results of P60 tests. With my simple collection of P60 hosts, I noticed out of the 501Bs, 502B, S-R5, and a SF L2T, the SF L2T performed the worse and does have a big black bezel on it.

Here's some test results I just did:

- P60 drop-in: Nanjg at 3.85A, XM-L2 U2 1A/Noctigon, 22 gauge wires, copper braided springs, SMO reflector, copper braided spring, alum foil wrapped

- SolarForce L2T host, copper braided tail spring

- fresh Panasonic PF cell

Results, in sequence:

- SolarForce flat SS bezel: 1,234 lumens at 15 secs

- L2T stock black bezel: 1,156 lumens at 15 secs

- SolarForce flat SS bezel: 1,204 lumens at 15 secs

Unfortunately, you can see some effect of the accumulated heat and/or cell droppage. I gave it a couple of minutes between tests, but probably not enough. I would say the effect of the black bezel is about 60 lumens loss from this test, or roughly 5%, compared to the low profile SS bezel.

5% is fairly significant for just a bezel difference.

[DB_Custom (Dale)]

But is it significant enough to actually be able to see? If you took a light out on a given night that had 60 more lumens than you’re used to, you quite likely wouldn’t even notice. Especially over 300 lumens.

JMPaul put an AR lens in the C8 he bought from me and took it from 77Kcd to 85Kcd. That should be a visible difference in throw.

So I suppose if you add up the little things, you’d get enough gain to be able to actually see it.

Like in my just completed M8, Sanyo UR18650FJ cells will make 5.25A while Samsung 20R’s net 6.77A! Sometimes the best mod is a battery swap.

[Tom_E]

5%'s do add up to 100%, eventually . This is what we do, little by little, with heavier wires, copper braiding springs, better cells, better thermal treatments, copper MCPCB's, higher bins, AR lens, centering/focusing emitters, etc.

It's all about efficiency - getting the most out of the parts. There's trade-off's of course of cost/looks/functionality vs efficiency.

If I had a really nice light but with a big black bezel, I'd think about grinding it down, removing the anodizing, polishing up the aluminum. Of course with a SolarForce, you always have the option of buying their low profile SS bezel.

Edit: Finally found it! Here: https://budgetlightforum.com/t/-/19458

I really have no reason to doubt these results - they seems very thorough, and lots of repeated tests. Basically he shows about a 4% improvement between the stock L2T bezel and the B6 SS bezel (here) - the two I tested.

[gitira6]

@comfychair

Ha! I recognize that little reflector… they do work well. I think I have about a half-gallon ziplock bag full of them by now…

I can relate to that, I have a ziplock filled with parts and reflectors too!

[Old-Lumens]

@comfychair

'Better hot spot' - you're gonna have to define 'better', lol. Could mean too many different things to different people. It may seem weird to pair a de-domed LED with an OP reflector, but it gives a really nice, usable output, doesn't it?

It works good with a de-domed XPG2 too, maybe better than with XML2. Depends on what you want from it though I guess.

Here's a teaser of a discarded prototype for a C8, I'll keep trying until I can make one with the plating still intact. Polishing isn't much fun. :(

Send it to me, I will polish it… and I will even send it back to ya.

[DB_Custom (Dale)]

Ok, rebuilt the copper shell P-60. I put a stock Qlite in it at 3.04A and I’m seeing 3.00A at the tail. I’m using an XM-L2 U2 1A, domed, and getting a start value of 969 OTF lumens. 969 at 3A as compared to what was it 863 at 4.5A? This is much better, more efficient, will run longer on a single 18650. But now it’s blue instead of green. sigh

It’s not bad though, and is definitely an intense P60.

[Tom_E]

The 20% loss rule for de-domed, and the de-dome and OP combo is quite odd - usually you de-dome for throw, but the OP knocks down throw. 20% still doesn't account for the full difference though, so maybe that de-domed XM-L2 was a T6?

Is that epoxy on the stacked 7135's and the wire connections? I've never seen that before, but could help I suppose - it's very neatly done work.

[DB_Custom (Dale)]

Of course, you’re right, but the shell design demanded pretty much that particular reflector and I didn’t find it in mirror finish. So you work with what is available.

The white stuff on the chip legs and contacts is Arctic Alumina Thermal Adhesive, put there as an insulator to avoid a short. I’ve taken to doing that when space constraints make me stack on the spring side and I want more power, I sometimes stack 3 high on the spring side and if using a spring I don’t want it to be able to compress into the legs. I put the AATA on the connections in an effort to prevent the reflector from shorting out, not having dealt with this one before. Mini potting, if you will. Usually, if stacking 3 high I remove the spring altogether and put a brass post there so it cannot short. Also gives better conductivity.

Wasn’t really necessary I suppose with that cylindrical spring that comes stock on a Qlite. Meant to put a different spring on it.