As long as you stay in voltage range the drop-in will work in solarforce.
For now, I'm using one drop-in from a 502B that has an XP-G R5 (I installed a different driver on it, but I could have used the original 1-mode driver if I wanted). I'm also using one I put together myself from an empty DX drop-in plus a driver and XP-G R4 LED. You can definitely mix and match as long as you keep in mind the voltage range of the drop-in. All of my drop-ins work best with a single lithium ion battery. In fact I can't even use the extension tube because none of my drop-ins will take 8.4V.
brted
From the pics you can really tell the quality. Lightake must make a big profit out off each unit.
Do I need to do any soldering/gluing if I just want to use the drop in straight from the 501B/502B?
No soldering. All you do is unscrew the head, put the drop-in in there, and put it back together. You literally just drop it in.
Thanks! I would rep you if there was that system here :)
Has anyone tried one of these Thrunite's XPG P60 Dropin's? I wonder if they are actually 493 lumens.
http://www.sbflashlights.com/Thrunite-Dropins-c18/
I ask because I still need a dropin for one of my SolarForce L2m's. I really like the Thrunite XPG 3 Mode 4.0-13V Dropin so I can use the 18650 extension tube and use 2 - 18650's. Thanks guys!
Someone tested the older Thrunite's XP-G R5 (2.7-9V Input) over at CPF. But I think they are too expensive, I wish they sold the dropin of the SKYRAY S-R5 separately. It's been one of the best budget dropins so far.
Hey brted,
What was the price you paid for the real Solarforce L2 on ebay?
$11.05. He had them on sale for 30% off. Then yesterday they were at regular price. Today they are 20% off (still a pretty good deal). If he goes 30% off again, I might pick up a black one, but I have more hosts than drop-ins right now so I don't need it at all.
Ok I just bought one from him. Now what's the best drop in for this thing? Thinking of getting 501B on DX with MC-E. Is that hole in your beam still there?
Cool. What color did you pick? You got the L2 for 18650?
I put a different reflector with the MC-E and it is a little better (not a distracting black dot anymore), but it is still there. An XP-G R5 is probably the best bet: bright, decent throw, good beam quality, and efficient. With the MC-E, it is bright and floody enough that you get a lot of light bouncing off things that are close to you (the ground, overhanging trees, etc.) that those objects blind you from seeing stuff in the distance that isn't lit up as brightly. At least for me.
The XP-G has enough spill, but puts most of the light where you want it. If you don't mind 1 mode, the XP-G R5 is good and seems reliable based on reviews and my experience. The 5-mode seems more iffy. I was happy getting the 1-mode and swapping the driver out for a 3-mode. But if you don't want to install your own driver and still want multi modes, you probably need to get the 5-mode.
I was debating between the black and gray L2 18650. I decided to get the gray one just like yours :) Thanks for the advice for the XPG R5 one mode. In Don's review he said his MCE's + sign can't be seen after 4 feet. In your pictures, there's a dark spot on your fence lol.
Is gray the same as gunmetal? 
Yeah I think it's the Gunmetal Gray
brted,
Which one of the 3 has the best heatsinking? Also, how does the Solarfarce compare to the 504B?
They could all probably use a few aluminum strips to get a tighter fit. I haven't done any duration tests on the 501B or the Solarforces yet, but I know the 504B tends to get hotter than the 502B which is a good thing. Part of that is because the inner diameter of the 502B is bigger plus the throat separates from the body tube whereas the 504B/Solarforces have one-piece body tubes and throat which will transfer heat better from the head. I'd expect similar peformance on the Solarforces, with maybe a little better performance on the real Solarforce because it feels heavier.
Here are measurements I took of the inner diameter of the heads of the lights. The drop-ins vary in diameter a little so the number of strips needed will vary from maybe 3 to 8 (for the 502B).
501B: 22.6mm; lightest weight
502B: 23.8mm; pretty heavy
504B: 22.5mm; medium weight
Solaforce L2 (fake): 22.5mm; medium weight
Solarforce L2: 22.5mm; heavier than the fake
I've chatted directly with a Solarforce rep and apparently there are Solarforce fakes out there, but he basically told me that it can't be helped in China. Although the irony here is that a Surefire 6P clone gets cloned...while the Ultrafires are 6P clones to a certain extent too, but of course they're acknowledged to be made by Ultrafire. As far as Daniel from Lightake saying they're genuine (despite his bad english), he is probably being honest with as far as he knows. Afterall, he is a Lightake salesman and not their purchasing manager and so he only knows the information given to him. With that said, since we all know the only Solarforce L2 that comes stock being able to tailstand is the L2P, the ones sold at Lightake are most likely are fakes...still for the price, you can't really complain.
And the L2r
Oops, forgot about the L2r and L2i as those do tailstand as well...but I was thinking about the CR123/16340/18340 standard L2 model.