ROP bulb best 4 cell bubl?

[apete2]

I purchased a whole bunch of the clearence 4.5ah D cells from radio shack and stuffed some into a 4d mag which is usually a sub C ROP. To my suprise, the ROP low bulb was still brighter than the 4 cell xenon, even though it was underdriven. It was a little yellower, though. Is there a better 4 cell PR bulb for output?

 

[Kestrel]

Is there a better 4 cell PR bulb for output?

Try the Pelican 3753-H, a 4.8v ~1.8 amp bulb (purchased in the '3754' pack). I've written a lot about it in my thread here.

 

[Juggernaut]

Your runtime is going to look like this:



Alkaline D cells will not take kindly to 1.8 AH, .75 is about max. With a Maglite stock bulb ".65A" 50% output is reached in 1 hour 30 minuets with 8 and one half hour remaining. At that sort of draw "1.8A" your looking at 10-15 minuets rapidly declining light and then a quick drop off to about 10% original output for a few hours:shakehead, not a very efficient set up, though I've seen worse.

 

[apete2]

It should be ok though with the radio shack 4500s, those are nimh

 

[lctorana]

4.5Ah for a D cell is a very common NiCad capacity.

For the sake of the charger you use (some are NiMH only these days), make certain about this.


Oh, and for the original question, please remember this.

 

[apete2]

Yes, they are NimH with a green wrapper, pre-Enercell branding. D Cell, 4500 stated mah. The local radio shacks had them on clearance for $4.99 for two.

I never saw that bulb before, thanks for the link.

 

[fivemega]

Is there a better 4 cell PR bulb for output?

Brightest 4 cell bulb CPF ever seen was custom made bi pin 4 volt, 3.5A axial bulb.
Next choice was WA1183 which is again bi pin and out of production now.
Third choice was WA1319 which is also bi pin and out of production now.

So your choices are limited to mentioned 3753-H or linked above.

 

[Kestrel]

I purchased a whole bunch of the clearence 4.5ah D cells from radio shack and stuffed some into a 4d mag which is usually a sub C ROP. To my suprise, the ROP low bulb was still brighter than the 4 cell xenon, even though it was underdriven. It was a little yellower, though. Is there a better 4 cell PR bulb for output?

Try the Pelican 3753-H, a 4.8v ~1.8 amp bulb (purchased in the '3754' pack). I've written a lot about it in my thread here.

Your runtime is going to look like this: <snip>
Alkaline D cells will not take kindly to 1.8 AH, .75 is about max. With a Maglite stock bulb ".65A" 50% output is reached in 1 hour 30 minuets with 8 and one half hour remaining. At that sort of draw "1.8A" your looking at 10-15 minuets rapidly declining light and then a quick drop off to about 10% original output for a few hours

Thanks for your input Juggernaut:

• Great runtime graph, I liked the X-axis and Y-axis particularly. What equipment did you use to collect the data? We have a lot of data collection equipment in our lab but I haven't yet used the 'Paint' application for data aquisition.
• You cite alkaline D's doing ~0.75 amp max. If you had read the thread I cited, you would have read the following for four alkaline C cells in post # 32:

Bulb is at 6.15V/1.72A. Much whiter and brighter than stock. On fresh alkaline C Cells.

• Another good resource for alkaline cells that you might find useful is Silverfox's Alkaline Battery Shoot Out thread. He doesn't have a runtime for alkaline D's at 1.8 amps, but for a (much more demanding) 3.0 amp load, he measured runtimes of 22 to 42 minutes (with an average of 32 minutes), much greater than your guess of "10-15 minutes" for the "1.8A" that you "cite".
• On top of the fact that:

It should be ok though with the radio shack 4500s, those are nimh

BTW, the OP asked:

Is there a better 4 cell PR bulb for output?

Note that runtime wasn't part of the OP's question. Although with his 4500 mAh NiMH's, he'd be looking at ~2-2.5 hrs of runtime or so. Let me just open 'Paint' to make sure...

 

[Kestrel]

Yes, they are NimH with a green wrapper, pre-Enercell branding. D Cell, 4500 stated mah. The local radio shacks had them on clearance for $4.99 for two.

I never saw that bulb before, thanks for the link.

You're welcome. :huh: If you try it out (the bulb pack is still on sale for US$7.50 at KC Specialty Products), please post your results (good or bad) in my thread. I'd like to find some use for the second (lower-output) bulb in that pack, the overall performance of that 3704-L appears to be rather poor.

Enjoy,
K

 

[apete2]

where did you get the 4.8v .375a bulb? That seems like it would match well with a 6v lantern for a long run time

 

[Kestrel]

where did you get the 4.8v .375a bulb? That seems like it would match well with a 6v lantern for a long run time

Yeah, it's a neat little Xenon bulb - they were taken out of two Specialized PreView Xe bicycle headlights I had lying around - comparable to the one I posted about in this thread. That's how I found the 3753-H, and ended up with two of those extremely efficient bulbs as extras. I have no idea where to find that 0.375a Xenon bulb on its own - it would make for a fantastic 'reserve' bulb in your Mag 4D tailcap wouldn't it - great for long runtimes in an emergency situation.

 

[Juggernaut]

Thanks for your input Juggernaut:

• Great runtime graph, I liked the X-axis and Y-axis particularly. What equipment did you use to collect the data? We have a lot of data collection equipment in our lab but I haven't yet used the 'Paint' application for data aquisition.
• You cite alkaline D's doing ~0.75 amp max. If you had read the thread I cited, you would have read the following for four alkaline C cells in post # 32:

Oh, I was using my auto correction spectrometeroo:, it works by applying a rudimentary amount of crude commonsense with past / hasty assumptions. It works quite marvelously when you want very inaccurate / over exaggerative answers to simple problems. I admit it's percentage of accuracy is only about 14.98% at best, but then again that number I just came up with was produced by my same faulty equipment
, so I'm not to sure how accurate that is either.

Seriously though I was just trying to reference the fact that under high amp loads the vast majority of alkaline capacity is lost, through internal resistance. At 1.8A draw the capacity of a alkaline D cells should last: (14Ah x 4.8 volts = 67.2 watt hours of capacity divided by 1.9 amps at the same voltage = 7.36 hours or 7 hours 23 minuets, and of course we know that will not be the case. Just my 2 cents.

By the way you really had me cracking up reading your analysis of my "scientific" data:laughing::laughing:!

 

[Kestrel]

Hi Jug, thanks for taking my post in such good humor. I admit that I was grumpier than I should have been when composing it, my apologies.

 

[Juggernaut]

That's fine.