2D Mag ROP question

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cdud09

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Mar 24, 2009
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Hello everyone! I'm in the process of doing a ROP mod with a 2D cell maglite. I have all the stuff needed besides a 2D to 6AA battery adapter. I am going to be using the high bulb from pelican. So my question is can I use a 8AA adapter instead of a 6AA adapter? If so is there anything that would change a ROP setup with a 6AA adapter?

I'm sure that this has been asked before, I looked but couldn't find a concrete answer.

Thanks for any help!
 
I have only ran a ROP with 6 cells(7.2v nominal)-8 cells(9.6v nominal) will blow the bulb!!!If you want to run a 8aa holder you will need to replace one aa with a 'dummy cell'(and you will have to guad-bore your host-if you don't know what I mean do a search).Even than you will have to rest the cells for several hours after charging.Two 18650 or 26500 li-ion batteries in a 2D is a better and cheaper option.:welcome:
 
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Thanks Andreas Ferrari! I appreciate the info. Any chance you know where to get a 6AA adapter? I tried finding one but they seem to be sold out.

I have never heard of a ROP using 2x18650 cells before, whats the runtime on that?

Thanks for the Welcome! :wave:
 
cdud09 said:
Thanks Andreas Ferrari! I appreciate the info. Any chance you know where to get a 6AA adapter? I tried finding one but they seem to be sold out.

I have never heard of a ROP using 2x18650 cells before, whats the runtime on that?

Thanks for the Welcome! :wave:
Click to expand...

Mdocod has 6AA adapters available: http://www.candlepowerforums.com/vb/showthread.php?t=223785

Running a ROP with 18650s is referred to as a ROP LE (lithium edition).
http://www.candlepowerforums.com/vb/showthread.php?t=143037

In a 2C body you have to do a tailcap mod, or run Downloads MagRing2 (currently out of stock): http://www.candlepowerforums.com/vb/showthread.php?t=178764

You could run two 18650s in a 3C body with a slight stretch of the tail cap spring. A pair of the new AW 2600 mah 18650s would run a ROP-H for 25-30 minutes. I made a cardboard tube wrapped in electrical tape to make up the diameter difference.

I'm currently running a Mag85 in a 3C body with three 25500 cells from Kaidomain, and a ROP-H in a 2C body with two 25500s. http://www.kaidomain.com/ProductDetails.aspx?ProductId=6645
These batteries are not 4000 mah, but based on my usage around 3000 mah.

Both have Borofloat lenses and these reflectors: http://www.kaidomain.com/ProductDetails.aspx?ProductId=5633

I also have a ROP-L in a 2C body but powered by two ultrafire unprotected 18500 cells.
 
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I notice the subject line mentions 2D rather than 2C. I currently have 4 ROP torches - 1 is a 6D ROP High (3854-H) and the other 3 are all in Maglite 2D hosts (3854-L, 3853-H & 3853-L). My 2D ROPs are all ROP LE because I prefer the characteristics of Li-ion cells (low self discharge and holding their voltage for longer). To fit 2 18650 cells in a 2D you need some PVC piping to stop the cells from moving too much. You can easily fit 2 x IMR 26500 cells if you use some PVC pipe and a short metal spacer (they are a bit short). You can also use cells like these, which are the same as these except in stock and with charger.

I really like the 2D size and shape and with a ROP LE you get really good light output (nice colour, plenty of Lumen). My 3854-L is my favourite - good light & colour and I get a couple of hours of run time from my KD protected Li-ion D-cells.
 
Wow I'm such a NEWB! I never heard of a R.O.P. using D-cell batteries. Is there a difference in runtime/output between using D-cells and AA cells w/ the 6AA to 2D adapter? I already have eneloops that I'm using in my TK40, and was planning on using them in the R.O.P.

Already have:
* Maglite 2D flashlight
* Pelican 3854 bulb
* Borofloat 52.1mm lens
* Metal reflector
* 6AA batteries (eneloop)

Need:
* 2D to 6AA battery adapter (probably getting the one from Odd Mods)

Would it be better to use the rechargable D-cells? And that would be called a R.O.P LE right?
 
The biggest problem that I have come across is that the protection circuit on the KD Li-ion D-Cells is a bit limiting. No problem with the ROP Low but the ROP high can pull enough amps so that it often will trip the protection circuit and the light wont turn on. The ROP high bulb also flashes at a lower voltage than the ROP low - so you can blow the 3854-H bulb pretty easily. The voltage sags under load much more with AA NiMH cells or smaller Li-ion cells, but with D cells they can hold over 4V per cells under load.

For the ROP low I like the KD Protected D-Cells, but for the ROP high I would tend to go with the unprotected cells or AW IMR 26500 instead.
 
Hi,

I didn't want to open a new thread, so here is my question:
my brother now owns a Mag 6D ROP (6x NiMH) - he used the Hi bulb most of the time. The Lo bulb was used in a light that has an internal battery pack consisting of 4x NiMH AAs (=4.8V). Though it was rather dim (compared to my Fenix TK20), it worked quite well. When he wanted to use the bulb in the Mag again, it was dead. I even measured its resistance: infinite.
Why is the bulb destroyed? :confused: Could you please help me?

Thanks for your help!
 
KiwiMark said:
The biggest problem that I have come across is that the protection circuit on the KD Li-ion D-Cells is a bit limiting. No problem with the ROP Low but the ROP high can pull enough amps so that it often will trip the protection circuit and the light wont turn on. The ROP high bulb also flashes at a lower voltage than the ROP low - so you can blow the 3854-H bulb pretty easily. The voltage sags under load much more with AA NiMH cells or smaller Li-ion cells, but with D cells they can hold over 4V per cells under load.

For the ROP low I like the KD Protected D-Cells, but for the ROP high I would tend to go with the unprotected cells or AW IMR 26500 instead.
Click to expand...
Don't the bigger Li-Ion D cells (LiCo or "safe" chemistry) drive the ROP-Hi too hard initially, therefore seriously limiting their life?
I'm trying to figure out if a bulb-slide mounted regulator would be a useful thing?
 
JimmyM said:
Don't the bigger Li-Ion D cells (LiCo or "safe" chemistry) drive the ROP-Hi too hard initially, therefore seriously limiting their life?
I'm trying to figure out if a bulb-slide mounted regulator would be a useful thing?
Click to expand...

If you blow the 3854-H bulb then maybe switch to a 3853-H instead? Flashing above 8.5V may be a pain, but flashing above 9.8V should be fine off pretty much any 2 Li-ion cells.
 
Seeing as the 3854 is more readily available than the 3853 7.2v bulbs, a regulator would be awesome for ROP's. It is not all that hard to flash the Hi bulb with larger NiMH/LiIon cells and resistance fixed mags. Besides this would allow for 8xAA to be used in a bored 2D for extended runtime.

Any chance of making these fit C mags also? If this is going to be ROP specific, there is no need for voltage adjusting pots, set the regulated voltage and battery cutout while loading the software into the reg.

Sounds promising.:naughty:
Nova
 
^^Nova^^ said:
Seeing as the 3854 is more readily available than the 3853 7.2v bulbs, a regulator would be awesome for ROP's. It is not all that hard to flash the Hi bulb with larger NiMH/LiIon cells and resistance fixed mags. Besides this would allow for 8xAA to be used in a bored 2D for extended runtime.

Any chance of making these fit C mags also? If this is going to be ROP specific, there is no need for voltage adjusting pots, set the regulated voltage and battery cutout while loading the software into the reg.

Sounds promising.:naughty:
Nova
Click to expand...
I thought it would fit inside the chromed bulb slide, under the bulb and above a shortened spring. I have to do a couple of mockups to see if it's even do-able. The components are easily small enough. Looks like the batteries would have to be installed backwards though.
 
Sounds good. I always lock the slide anyway. Having to put the batteries in backwards may be a pain though, especially for those using battery carriers, I would rather modify the switch if there was a choice. You would want some good reverse polarity protection.

Cheers,
Nova
 
^^Nova^^ said:
Sounds good. I always lock the slide anyway. Having to put the batteries in backwards may be a pain though, especially for those using battery carriers, I would rather modify the switch if there was a choice. You would want some good reverse polarity protection.

Cheers,
Nova
Click to expand...
Reverse polarity protection would be an absolute necessity if batteries need to be installed backwards. A good Diode will protect the whole system, but you'll loose 0.7-0.9V through the diode though. If you just want to protect the electronics bits, a smaller diode can be used. However, reversing the batteries will pop the bulb.
If folks don't mind locking the slide, that makes things easier from the standpoint of modding the switch. You just run a wire from the top of the switch to the slide-screw, then another wire from the grub screw to the bottom center of the slide.
The whole regulator would fit inside the slide. Nice and tidy. It could be epoxied in place by potting the bottom half in high-temp epoxy, just 1 wire hanging out the bottom.
Of course I'd need to find a bunch of bulb slides to start with.
 
I usually drill a hole about 2/3 of the way down the slide and screw it in place there, keeps the head screwed on a fair way then. I can also undo this if i need to (never have found the need though, I don't tend to change the focus much).

As for the switch, maybe a change-over type arrangement. Send in a vanilla switch, get a ROP regulated one in return?

Cheers,
Nova

ps. great work on your other regulator, looking gooood.
 
^^Nova^^ said:
I usually drill a hole about 2/3 of the way down the slide and screw it in place there, keeps the head screwed on a fair way then. I can also undo this if i need to (never have found the need though, I don't tend to change the focus much).

As for the switch, maybe a change-over type arrangement. Send in a vanilla switch, get a ROP regulated one in return?

Cheers,
Nova

ps. great work on your other regulator, looking gooood.
Click to expand...
I dont' want to hi-jack the OPs thread any more, but...
That's what I was thinking. I woul dneed a few to get started with at first, then when orders were placed, I'd do the "exchange system".
 
Hi,

I wanted to add something (see my question above): the ROP Lo bulb was alive again for just a second when my brother switched it on just for fun. But then, it went out again. Is there something I can do? Perhaps the bulb has just loose contacts somewhere.

Thank you :)
 
Bulbs die. They don't have a particularly long life (compared to LED's), especially when overdriven. With 6 NiMH AA batteries you haven't tried to put too much voltage through it so it must have been ready to go anyway. Try another one, it should work fine.

Cheers,
Nova
 
^^Nova^^ said:
They don't have a particularly long life
Click to expand...

But we used it hardly for half an hour...and when we saw it flash, it was driven by just four NiMHs - so it couldn't go :poof:!?

BTW, what is the average life time of a ROP bulb?
 
Nova's right. Some bulbs last freakishly long, others don't live long at all even under normal drive conditions. Such is the statistical variability of a manufacturing process.
Get yourself a nice brand spankin' new bulb and enjoy.
Mourn not the failed bulb, but rejoice in the light it did provide.
 
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