ROP Question

[RichS]

Does anyone run their ROP hi bulb with IMR batteries? I wasn't sure if the bulb could handle the output of IMRs. I would think it would be much brighter on IMRs if it wasn't too close on the border of "poof"...

Thanks in advance!

-Rich

 

[StorminMatt]

I don't see why you couldn't run a ROP bulb with IMR batteries. Remember that many people run this light from 6xNiMH. And 2xIMR is roughly the same thing. The only real difference is that, although they both start off at about the same voltage, NiMH drops rapidly to a plateau while the voltage of IMR drops more or less linearly until it is discharged.

 

[mvyrmnd]

I've done it, but you may find the odd bulb will not handle it.

 

[ElectronGuru]

There are two versions of the ROP bulb. The higher voltage model (forget the number) handles the lack of sag from IMR, better.

 

[fivemega]

3854H will most probably flash with 2 freshly recharged IMR 18650 if your flashlight resistance is low but works fine with stock (unmodified) M*g 2C and M*g 2D
The reason I mentioned MOST PROBABLY is because I flashed several and few servived.
3853H works without problem even in resistance fixed flashlight.

 

[RichS]

3854H will most probably flash with 2 freshly recharged IMR 18650 if your flashlight resistance is low but works fine with stock (unmodified) M*g 2C and M*g 2D
The reason I mentioned MOST PROBABLY is because I flashed several and few servived.
3853H works without problem even in resistance fixed flashlight.

Thanks so much for all the replies - much appreciated. So I looked, but it seems that only the 3854H bulbs are currently available. Do they still produce the 3853H, or are those an older model that is no longer being produced?

Looks like the 3854H are too close to the boarder of flashing boarder to be considered a reliable solution for me. Guess I'll have to stick with the 1111 and 18650s.

 

[Kestrel]

The nice thing about the 3854's is that the -L's are useful as well, they have quite a bit of voltage headroom before insta-flash.
The 3853-L's don't have as much headroom or output and are less useful.

2x LiCo 18650's have so much more capacity these days that they are a near-optimum pairing with the 3854-H's @ a manageable ~1.4C, moreso than 2xIMR 18650's with the 3853-H which should provide somewhat less output and perhaps less runtime. It has been a while since I've thought about these combos though.

 

[mvyrmnd]

The nice thing about the 3854's is that the -L's are useful as well, they have quite a bit of voltage headroom before insta-flash.
The 3853-L's don't have as much headroom or output and are less useful.

2x LiCo 18650's have so much more capacity these days that they are a near-optimum pairing with the 3854-H's @ a manageable ~1.4C, moreso than 2xIMR 18650's with the 3853-H which should provide somewhat less output and perhaps less runtime. It has been a while since I've thought about these combos though.

Kestrel makes a very good point - two good quality 3400mAh LiCo's will drive a 3854H really very well, with less risk of than IMR's - and twice the runtime.

 

[fivemega]

The nice thing about the 3854's is that the -L's are useful as well, they have quite a bit of voltage headroom before insta-flash.
The 3853-L's don't have as much headroom or output and are less useful.

2x LiCo 18650's have so much more capacity these days that they are a near-optimum pairing with the 3854-H's @ a manageable ~1.4C, moreso than 2xIMR 18650's with the 3853-H which should provide somewhat less output and perhaps less runtime. It has been a while since I've thought about these combos though.

Kestrel makes a very good point - two good quality 3400mAh LiCo's will drive a 3854H really very well, with less risk of than IMR's - and twice the runtime.

It's not about capacity or 1.4C or anything else.
2 Protected New and fully recharged 18650 will NOT power up a ROP 3854H with single click. You will end up with double or triple click and in long term damage PCB

WA1111 is brightest bulb that can be direct drive with pair of protected 18650 (3400mAh) with single click. This is an excellent choice with about 50 minutes of safe run time.
However, if you use voltage regulation, current regulation or soft start, you will be fine with 3854H or even Philips 5761
Please keep in mind to use healthy and good brand protected cells like AW's or Redylast. I don't use or have experience with cheaper brands.

 

[mvyrmnd]

I bow to your wisdom and experience, fivemega, but two 3400's will indeed power up a 3854H on the first click - I've just done it.

 

[Kestrel]

I've also done it with the older AW 2600's. Perhaps it comes down to host resistances.