# Bulb options for ALKALINE powered 6D-cell....



## jwl (Feb 5, 2006)

I've got a 6D Mag coming and I need some suggestions for bulb options that I can run. It looks like the KPR118 is one possibility. Any others?

The only rechargables I have right now are Rayovac Renewal Alkalines but I do plan on getting some NiMH later (CTA 12,000Mah D-cells). Then I'll do the ROP.

:thanks:


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## FredM (Feb 5, 2006)

If you plan on getting the NiMH batts later anyways I would leave it stock or just go for a Xenon upgrade if you like.


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## Yooper (Feb 5, 2006)

Drop in a ROP bulb. Not as bright as on NimH batteries, but works fine and probably brighter than any other bulb you'll try. 

If you use the low output ROP bulb you can still use your plastic reflector and lens. I did this for a long time before I finished building my ROP (ended up using 7 C's, MOP reflector, and UCL) with no problems at all.


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## jwl (Feb 5, 2006)

Yooper - Which ROP bulb set did you get that ran with the alkalines and where did you get them?

Thanks.


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## nickz (Feb 5, 2006)

The 3854 BIG D SLA bulbs. Make sure you get the 3854's for the sealed lead acid light.


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## FredM (Feb 5, 2006)

Lighthoud has them.


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## Yooper (Feb 5, 2006)

What nickZ said, part number 3854, available from lighthound.com or directly from Pelican. I bought mine from Pelican before I knew they were available elsewhere. Lighthound's price is better.

3854 is a two bulb pack. There is an 11W bulb and a 24W bulb. The 11W bulb should be safe to use with your Mag plastic reflector and lens, using alkaline batteries. If you upgrade to better batteries or the high output bulb, then it's time to get a glass lens and a metal reflector, as the plastic ones will melt.

You won't hurt anything by using alkalines, the light just won't be as bright as it would with good NiMH batteries because the alkaline batteries will exhibit voltage sag with the high current load.

I guess I should add that I have no experience with rechargeable alkalines - I suppose you could damage them by overdriving them this way. With regular alkaline primaries you'd just get a shorter runtime.


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## jwl (Feb 5, 2006)

Anybody ever try the #3804 Big 6D Alkaline bulbs, they are only 8W and only draw 1.1A. Supposedly a 6 hr run time according to Pelican. 

Do you think they would be as bright as underdriving the 11W (1.5A) SLA bulb?


I already have the UCL lense just need to get the metal reflector and better batteries to run the big bulbs later on.


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## Yooper (Feb 5, 2006)

That would certainly be a safer choice, but I haven't tried them. Somebody on cpf was going to do a direct comparison of the 3804 and 3854 but I don't remember who....


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## nickz (Feb 5, 2006)

The thing is, you are not underdriving the 11W LOLA 3854 bulb in the 6D configuration. You are overdriving it really hard although the alkalines will sag fairly well and that is what I think prevents blowing the LOLA bulbs. IIRC, the Big D SLA bulbs are rated at 6v. Most overdrive the LOLA with 6aa's nimh with a nominal voltage of 7.2v. Running alkalines in a 6D light, you are pushing 9V in theory through the bulb (not taking sag into consideration). At that rate you are overdriving the bulb 50%. It has worked for me in the past but I have no idea of bulb life in this configuration. On the flipside of that, I do not know what the alkalines sag to. You would have to take an amp reading with the light running and figure out the voltage the bulb is seeing to figure out just how hard that configuration is overdriving the bulb.


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## Yooper (Feb 5, 2006)

What nickz says is all very correct of course, but my personal experience with 6 brand new Energizer D cells and an 11W ROP bulb is that it's not nearly as bright as the same bulb driven with 6 CBP 1650 AA's nor as bright as the same bulb driven with 7 NiMH C cells (which configuration instaflashed a 24 W ROP bulb). I slightly modified the Mag switch for lower resistance by soldering the spring caps on and I treated every contact surface in the light with DeOxit and ProGold, so the batteries' voltage sag was about the the only thing protecting the bulb. I used the light quite roughly, as a work light for my Land Cruiser on the trail, dropping it and knocking it against stuff often while powered up, and had no problems.

So in my case there was plenty of voltage sag.

I used the light quite a bit on the alkaline D cells, getting at least half an hour of bright runtime out of those batteries before I upgraded the light to a real ROP. The batteries are far from dead, some of them currently residing in a 3D Mag body and doing fine.

Just do it!


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## nickz (Feb 5, 2006)

I have been very happy with my 2D ROP's using 7aa nimh for sure. Never tried the 7C config, but it is sure to give great runtime.


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## Yooper (Feb 5, 2006)

From what I've been seeing here on cpf, 7 cells is on the edge for a ROP bulb. I flashed a ROP HO bulb with 7 freshly charged C's, but this 11W bulb is doing fine. I'm using Titanium 5000mah C's from Amondotech. Lesser C's might not be a problem.

nickz, are you using CBP1650's in your 2D ROPs? I wonder if CBP vs. non-CBP would make just that little bit of difference...


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## nickz (Feb 5, 2006)

Yes, I am using CBP's but I also rest my cells for 4-6 hours before lighting it up.


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## jwl (Feb 5, 2006)

Do you guys see any problem with running 6 D-cell 12,000Mah CTA brand cells with either the HO or LO ROP bulbs? Do you have any idea what the run time would be?


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## Yooper (Feb 5, 2006)

I see no problem. The ROP specification is for 6 cells. A HO ROP bulb is using about 28W at 7.2V, which is about 4 amps. In series you get the average amp-hour rating of each cell in the pack, or 12 amp-hours in this case. That would give you about 3 hours runtime. The LO lamp at about 13.1W would be more than 6 hours. I think.

What I don't know if is those cells can handle 4 amps well. If not, they will just sag a bit and not last as long. Probably some of the nicest D cells out there, though.

Sounds like a sweet light.


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## Dave Bui (Feb 7, 2006)

does anyone have have an idea of how the 3804 alkaline version bulbs would do with 2 3.7 lithium C size batteries. this is something i want to try but im a total noob with this kinda stuff. any comments are greatly appreciated.

thanks
David


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## Templar223 (Feb 8, 2006)

Yooper said:


> If you use the low output ROP bulb you can still use your plastic reflector and lens. I did this for a long time before I finished building my ROP (ended up using 7 C's, MOP reflector, and UCL) with no problems at all.



Yeah, for about three to five minutes continuous before bad things begin to happen.

Seven minutes top before things start to smoke. Things start really falling apart before ten minutes roll around.






See my recently done torture test post:

https://www.candlepowerforums.com/threads/106993

John

Edit to tweak link.


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## jwl (Feb 8, 2006)

Templar223 - Nice test!!!

How hot did the head of the Mag get? Do you think that using a 'finned' head would help with the heat problem? Obviously not going to do away with the need for metal parts, just wondering if it would run noticeably cooler. (I still plan on getting a metal reflector.)


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## Yooper (Feb 8, 2006)

Nice work John! I would expect that if you used alkaline batteries, which is what we were talking about above, that you would not have had any damage, and you also would not have achieved as much runtime. What is the average capacity of an alkaline D cell? I don't even know. Surely not 7 ah like your NiMH batteries...


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## bfg9000 (Feb 9, 2006)

Yooper said:


> What is the average capacity of an alkaline D cell? I don't even know. Surely not 7 ah like your NiMH batteries...


Alkaline D cells have around 18Ah capacity at very low outputs. SilverFox showed here: https://www.candlepowerforums.com/threads/64660 that it drops to about 5-8Ah at 1A draw, and 1-2Ah at 3 amps due to high internal resistance. At ~two amps with the LO assembly, it should be somewhere between those. Note at 1A they're good for an hour until 1.2v, but only a few minutes at 3A. Most alkaline D flashlight bulbs seem to top out at 0.85A for this reason, so the best compromise would likely be a 5-cell krypton bulb overdriven on 6 alkaline cells.


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## Flakey (Feb 9, 2006)

Jwl,

i would warn you about using 6D cells, D and even C cells hold their charge alot better than sub C cells do you might be looking at serious instaflash risk, give em plenty of rest off of the charger!


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## andrewwynn (Feb 9, 2006)

if you are not stuck on incan, the BAM will be an awesome solution for 6-cell lights.. with 2 or 3 emitters the battery current can be below an amp, especially on medium power. I have yet to run tests, but will do so. 

-awr


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## jwl (Feb 9, 2006)

andrewwynn - Looks interesting, nothing is necessarily out of the question. I may get another 6D later, that way I can have 1 for LED and 1 for incandescent.:rock:


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## jwl (Feb 12, 2006)

Pelican #3854 bulbs ordered - $10.63 with shipping.:rock:


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## Templar223 (Feb 12, 2006)

jwl said:


> Templar223 - Nice test!!!
> 
> How hot did the head of the Mag get? Do you think that using a 'finned' head would help with the heat problem? (I still plan on getting a metal reflector.)



Thanks on the test. It was fun, although I wished I'd been there for the first seven minutes. I never dreamed things would start going south so quickly!

The head of the light was half-warm (maybe 85-90ish degrees tops). The lens was almost too hot to touch long before it started to distort/melt.

I let my gf's nieces and nephew play with two ROP/Lo lights outdoors in 20-odd degree temps for almost a half hour around Xmas time and they were running the lights pretty hard and I saw zero problems which is why I was so shocked about the indoor "controlled" test heading south so quickly.

Moral of the story: I have a couple of the ROP/Los with stock parts still for experimentation and play, but for the two "search and rescue" lights (the "serious" ones I may count on when the going gets tough), are outfitted with all high-temp stuff. Murphy will come to play when you need him to stay away!

One other point of note: I noticed the Mag6D was operating erratically after the test with new parts. Upon further examination, *I noticed the lead base on the bulb was perfectly melted *to the shape of the little wedge in the Mag socket assembly during that 30-odd minute test run. That bulb must have reached into the 500+ degree F range for that lead to get that soft (melting point of lead is in the low 600's I believe). No damage to the lamp assembly though. Everything on the lamp assembly works just fine and a new bulb solved the intermittent failure to burn problem.

I did have a near miss on damage with a Mag85 that when I was cooking the new potted bulb (sans head, reflector, etc.) I "forgot" it was running and about fifteen minutes later, it was so hot that the lamp assembly seemed soft.

I let it cool and I pushed the lamp socket down and it didn't pop right back up. With a little TLC and working it back and forth a little, it was virtually good as new. 

John


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