WA1164 vs 3854-H ROP

Greetings Everyone,

I have never really given the ROP bulbs much consideration. I don't know why, but I guess I always assumed that if the bulb would fit into a Mag without modification, it couldn't be any good.

But recently I have been reading more ROP posts, and spending more time looking at LuxLuthor's destructive bulb test results. It seems that I have really overlooked some very nice bulb options.

So, I am looking for your opinions on these two Mag hotwire builds:

Mag 2D with 6 AA Elite 1700s running a 3854 ROP
Mag 2D with 8 AA Elite 1700s running a WA-1164

Both builds would use an FM-bifocal reflector and would be direct drive (at least until AW's switches are available again).

Based on Lux's destructive testing for the 3854-H and the 1164, I would expect the current draw from the 3854-H to be about 10% higher (4.8A vs 4.4A), but the lumen output looks to be relatively similar.

So, the numbers would indicate that these two setups would be relatively equivalent. The advantage I would see with the 3854-H is that I would not need a bi-pin adapter and would not need to bore the Mag battery tube.

Seems to me that the 3854-H wins on cost (2 fewer batteries, no bi-pin adapter and no battery tube boring needed) and would be equivalent in performance.

What am I missing?

Cheers,
Battery Guy

Most of the ROP info and the various bi-pin builds I've read about are in the /Incan subforum, you might like to have a mod move this to there?

The 3854 ROP's are a lot of fun, one advantage to going that way is that you have access to the 3854-L bulb as well, less output but actually nearly comparable in throw (smaller filament - tighter hotspot) from what I've read, but more than double the runtime.

Another advantage to the 3854's is that you also have the option for 2x 18650 LiIons, the voltage is slightly higher than 6x NiMH in series (~7.4 vs ~7.2, but I guess you know that already ). The advantage to that option is that can save money with regards to a battery carrier, just use a PVC sleeve instead. I've done both and I find 2x 18650 to be more convenient.

Also, from what I gather, you don't need the high-discharge NiMH's, Eneloops are the preferred cells for the 3854 NiMH builds.

Kestrel said:

Most of the ROP info and the various bi-pin builds I've read about are in the /Incan subforum, you might like to have a mod move this to there?

Click to expand...

Certainly happy to have this post moved wherever it is most appropriate.

Kestrel said:

Another advantage to the 3854's is that you also have the option for 2x 18650 LiIons, the voltage is slightly higher than 6x NiMH in series (~7.4 vs ~7.2, but I guess you know that already ). The advantage to that option is that can save money with regards to a battery carrier, just use a PVC sleeve instead. I've done both and I find 2x 18650 to be more convenient.

Also, from what I gather, you don't need the high-discharge NiMH's, Eneloops are the preferred cells for the 3854 NiMH builds.

Click to expand...

Not planning lithium-ions, at least not yet. Besides, staying above 7.4 V for at least half of the discharge is not a problem for the Elite 1700 cells for currents in the 4-5 amp range.

With respect to the eneloops vs Elites, based on the test results I posted here, one would expect a 0.1 V per cell increase in overall voltage at 4-5 amp discharge. This would equate to ~0.6 V increase for the 3854-H hotwire build, which is pretty significant with respect to the lumen output of this light.

So I understand that 3854-H ROP builds are really great, but is there any reason to consider going with an 8 AA WA-1164 build instead?

Thanks for the input Kestrel!

Cheers,
BG

BG, you are not really missing much in your analysis. The huge popularity of the ROP & number of posts about it verify that as well.

The Pelican 3854-H is an excellent bulb, comes in a combo pack for $10, saves the money of buying a bipin adapter, and are readily available. It is a little wider bulb, so need to make sure you get a metal reflector that is not bored for the WA bulb. I don't know what the rates life is, nor how long it lasts with the stress of overdriving without a soft starter.

The 1164 is also a great bulb, but if you didn't get it already, it is a discontinued bulb. It tolerates a higher % overdrive with slightly less current required, and has a 2500 hour rated life (@ default 6V spec), so will do better with direct drive tolerance.

I would have to setup two lights side by side at their optimal voltages to compare which looks nicer in terms of beam shape, filament artifacts, white color, etc. I was surprised at how well the Pelican bulb performed when I got around to testing it.

If you don't mod the Mag switch and tail spring for low resistance, then the Elite's ability to hold a higher voltage than the Eneloops may be wasted.

I think the 3854H ROP is a great setup -- very simple and inexpensive, with high performance.

The 1164 requires boring to fit 8AA in a 2D Mag, needs two additional cells in the carrier, and draws more wattage than the 3854H, which probably means hotter operation.

With your equipment, can you check the holders for their contribution to the overall parasitic resistance? I found that switching from an mdocod 6AA->2D holder (loaded with Eneloops) to 2xIMR Li-ions increased the current draw by about 10% for my ROP.

Battery Guy said:

What am I missing?

Click to expand...

For continuous long run, positive globe of ROP Hi will melt. Also, you will get slightly long run with 1164.

LuxLuthor said:

The 1164 is also a great bulb, but if you didn't get it already, it is a discontinued bulb.

Click to expand...

This is not a problem because it's twin brother (WA1268) is still in production.

fivemega said:

For continuous long run, positive globe of ROP Hi will melt. Also, you will get slightly long run with 1164.

This is not a problem because it's twin brother (WA1268) is still in production.

Click to expand...

Hey FM

I don't understand what you mean by "For continuous long run, positive globe of ROP Hi will melt."

What is the "positive globe"?

Also, where can one find WA1268 bulbs for purchase?

Cheers,
BG

There have been a few reports that the (+) solder blob on the 3854H PR-base is borderline with regards to temperature and has deformed (compressed) slightly during continuous runs.

If the ROP bulb's solder blob is of Pb-Sn eutectic composition, the melting temp is still over 180C. Any ideas what the solder blob composition is for other PR bulbs? If they are mostly lead (i.e., in the alpha phase region, then the melting temp can be a lot higher than for the eutectic. I'd be amazed if that were the case, though. My suspicion is that many ROPs do not incorporate low resistance fixes and the Mag switch gets really hot, heating up the bulb in the process. An 1164 bi-pin doesn't use a solder blob. Does the bi-pin to PR adapter have a solder blob, or is it a solid brass or similar contact?

Justin Case said:

Does the bi-pin to PR adapter have a solder blob, or is it a solder brass or similar contact?

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The bipin to PR adapters made by FiveMega are either brass or stainless steel, machined and the pins isolated by ceramic...the mag tower will melt before your adapter melts

Illum said:

The bipin to PR adapters made by FiveMega are either brass or stainless steel, machined and the pins isolated by ceramic...probably not going to melt at all

Click to expand...

Yes, I know that the shell of the adapter is brass or stainless. But the bottom has to make contact to the Mag tower. Is that contact solder, solid brass, something else? From FM's 6th run sales thread, it looks like the contact is a brass plunger.

Justin Case said:

If the ROP bulb's solder blob is of Pb-Sn eutectic composition, the melting temp is still over 180C. Any ideas what the solder blob composition is for other PR bulbs? If they are mostly lead (i.e., in the alpha phase region, then the melting temp can be a lot higher than for the eutectic.

Click to expand...

Well, I do believe that we have a closet metallurgist on our hands!

Cheers,
BG

Battery Guy said:

Also, where can one find WA1268 bulbs for purchase?

Click to expand...

Here ya go:
http://www.cpfmarketplace.com/mp/showthread.php?t=220836

Though, I'd say 1164 is better, more lumens b/c of less weavel's.
Or, it's just because I have them.

More pertinently, 8 Eneloop fit in any stock m@g if all label seams are turned inwards. There was a post about it during the early waves of ROP but I've long since lost the link. I use this for custom (self-made) packs as well as Modamag 8x holder. I can't say if it works for FM or other battery holders.

Go with the 1164 (1268); an 8s 2D m@g has better weight then 6s.

Best,
Linger

Justin Case said:

Yes, I know that the shell of the adapter is brass or stainless. But the bottom has to make contact to the Mag tower. Is that contact solder, solid brass, something else? From FM's 6th run sales thread, it looks like the contact is a brass plunger.

Click to expand...

yep, its a plunger...milled along with the pin slot.

I have not seen that ROP bulb finding, but I don't doubt FiveMega's knowledge on such matters. I have long had a sensible guideline to not use incands for long, continuous stretches, using external head 'hot to the touch' being my sensible guide that also protects internal parts.

There are many out there who want a simple drop-in bulb solution that has that WOW factor output, so for them the 3854 is an excellent choice, and there has been tons of positive feedback on using it. If you don't mind bipin adapter setup, the 1164 is also great.

I wouldn't let the weight of 6 vs. 8 cells become an issue, without adding the cost of 2 more cells + bipin adapter setup + internal bore for 4 wide.

Mags are notorious for not having consistent internal diameters, not only from Mag D series to series, but Mag to Mag, and also the same I.D. along the entire length of the Mag. Those that say you can reliably fit 4 wide AA's without boring by turning the label to keep the overlap edge towards the inside are not being realistic. That is from direct experience.

If you don't mind the extra cost, the other option is get both setups! LOL!

A further clarification on the 'quadAA in any D m@g,' it is with eneloops and duraloops that I can prove. AA cells are notorious for not having consistent diameters, not only corporation to corporation, but between individual product lines as well. As such, the picture below with duraloops is not possible with duracell 2650's.



Modamag's 8aa visible inside a 3D.

LuxLuthor said:

Those that say you can reliably fit 4 wide AA's without boring by turning the label to keep the overlap edge towards the inside...

Click to expand...

More pics available upon request as I have put this 8aa holder in all of my D mags...but an easier proof just to take your 4AA cells, arrange them 2x2 in a square, label seems towards the center, and see if they'll fit up yer' m@g. If not, you may have to use eneloops.

If anyone has the link to the original CPF post documenting this (circa2007, quad AA's w/o boring) I'd be grateful.

Best,
L