DB1000 and LuxIII Runtimes

[darkzero]

Anyone know what the runtimes should be on 2x123s? Tylerdurden, I know your anxiously building one and I'm anxiously curious. Please let us know how long it runs and how much darkness it can turn to zero!

I'm building a DB700 & R2K in a Mclux PR head for throw then these LuxIII's finally hit the market and now I'm having doubts. After all I do have some on order w/ Wayne @ EL and now they're in stock. Should I just wait and do the III?/ubbthreads/images/graemlins/thinking.gif

Or I could just do both if the PR heads get back in stock.
Damn I hate being a flashlight junkie (actually not). Need more light, need more light./ubbthreads/images/graemlins/crazy.gif
Decisions, Decisions.... /ubbthreads/images/graemlins/icon3.gif

 

[jtice]

Dark,

I just did a PM6 with DB700 and R2K. Look in the Mod Assembly Help thread.
Its BRIGHT. You wont be disapointed in it.
I also plan on making a PR Mclux with a Lux III. I am curious how those with compair to each other.

You can expect alittle under 2.5 hours runtime from the DB700 R2K.

I am not sure about the DB1000 Lux III... I think you should get at least 1.5 hours.

 

[Doug S]

[ QUOTE ]
darkzero said:
Anyone know what the runtimes should be on 2x123s? Tylerdurden, I know your anxiously building one and I'm anxiously curious. Please let us know how long it runs and how much darkness it can turn to zero!



[/ QUOTE ]

You asked this at just the right time. Just last night I finished measuring the efficiency of the Downboy at various input voltages and output currents. I should be able to give you a very accurate estimate. For your particular scenario, you are looking at an input of about 5.2V and an output of 3.9V [datasheet typical for Lux III at 1000mA]. The DB is 85% efficient under these conditions. Your input power will be (1.0A X 3.9V)/.85 = 4.6W or 2.3W/cell. Using the Duracell datasheets, at this power level a 123 can deliver about 2.5 WHr so you are looking at 2.5WHr/2.3W = 1.09 Hr to dropout. Output will continue at decreasing levels beyond dropout and will likely have a lengthy "moonmode". Total extractable energy from LiMnO2 123 cells really starts to drop off steeply at around 1.5W. IMHO you are taking a very large decrease in runtime to get the marginal increase in brightness obtained by going from 700 to 1000mA drive level.

 

[McGizmo]

Doug,

The 5.2 V is the voltage drop across 2x123 given the current demand?

Thanks,
Don

 

[Chop]

I have to agree with Doug S. I don't know all of the formulas, but I can tell you what I've seen.

I was really hot on the KL1 for a while and can't tell you how many I've modded.

I'll use the stock KL1 circuit as an example. In stock form, the KL1 will give you about 4 hours of in regulation runtime. When I bumped the current up to 700mA, I got roughly half of that. When I bumped the current up to ~1A, I was getting right around an hour of runtime with Q3J luxeons.

It seems that at 1A a big load is put on the batts. Maybe Surefire cells would fare better, since they are supposed to be designed for high draw devices, but I don't know.

If runtime is important to you, go with the 700mA. With the luxeon 3, you'll only gain 15 lumens and that isn't much. You may be able to tell the difference when comparing side by side, but not in normal use. If you're in a situation where the extra 15 lumens would make a difference to you, you'd probably be better served by a bigger light.

 

[Doug S]

[ QUOTE ]
McGizmo said:
Doug,

The 5.2 V is the voltage drop across 2x123 given the current demand?

Thanks,
Don

[/ QUOTE ]

That's right, Don. I was really generous in my reading of the datasheet with that 5.2V. An interpretation of 5.0V may be better. BTW, of the various manufacturers datasheets for the 123 and 223 batteries, I find the Duracell ones to be most useful as they give both constant power and constant current performance data. Everyone modding around these cells should keep a copy of the Duracell datasheet on their hard drive.

 

[dat2zip]

Very interesting. /ubbthreads/images/graemlins/smile.gif

Wayne

 

[darkzero]

Txs Doug S. If I'd be taking a bit hit in runtimes from 700ma to 1000ma, I'll stay away from that bump up in current draw. After all 15 lumens really is not that much increase for decrease in battery runtime as stated.

But how much difference in brightness would I see in ditching the R2K for an LuxIII (emitter bin unknown, from Elektrolumens) running at 700ma. I'm led to beleive that LuxIIIs are just high quality/binned 1Ws that run better or more efficiently overdriven. Usually "in the real world" taking the place of 1watters from bin S and up. R and S bin aren't very far apart and I don't think 700ma is killing the 1watter's life anymore than it is the LuxIII. PLEASE clear this up if I'm way off.
txs

 

[Chop]

darkzero,
I can't comment on the LuxIII's yet because I haven't received mine yet, but I can say this. The R2K's I've seen have been real scorchers. I just sold an R2K in a KL1 that was driven up to 1A and that thing was ungodly bright. The light coming out of that little KL1 was as bright or brighter than my 3 cell M@g mods direct driving Q3J's with Fraen optics.

You probably won't see too much of a difference going to the LuxIII. I say, build 'em both and see for yourself. /ubbthreads/images/graemlins/grin.gif

 

[kj]

I tried to follow Doug's calculation for a BB700 5W on 2x123 configuration, but I'm not sure if my calculation is reasonable. Can someone double-check?
---
Assuming the efficiency of BB is roughly 80% and the typical Vf of 5W is 6.84V, the power drain from a cell will be:

(6.84V x 0.7A) / 80% = 6W
6W / 2cell = 3W/cell

According to Delivered Energy vs. Power Drain chart in the Duracell data sheet, one 123 cell can deliver about 1.8Wh. Thus, the regulated runtime will be:

1.8Wh / 3W = 0.6 hour = 36 min

 

[Doug S]

[ QUOTE ]
darkzero said:
Txs Doug S. If I'd be taking a bit hit in runtimes from 700ma to 1000ma, I'll stay away from that bump up in current draw. After all 15 lumens really is not that much increase for decrease in battery runtime as stated.



[/ QUOTE ]

I really doubt that you would see as much as 15 lm gain. That 15 lm figure comes from people subtrating the datasheet typicals for 700mA from 1000mA. Remember that those datasheet values are for a Tj = 25C which you don't have. Furthermore, whatever the temp at 700mA, you will be higher at 1000mA thus further reducing the gain.

[ QUOTE ]
darkzero said:
But how much difference in brightness would I see in ditching the R2K for an LuxIII (emitter bin unknown, from Elektrolumens) running at 700ma. txs

[/ QUOTE ]

Who knows? It would depend on the individual LEDs. It is entirely possible that are R bin 1W would be brighter than an S bin Lux III at the same drive current.

 

[Doug S]

[ QUOTE ]
kj said:
I tried to follow Doug's calculation for a BB700 5W on 2x123 configuration, but I'm not sure if my calculation is reasonable. Can someone double-check?
---
Assuming the efficiency of BB is roughly 80% and the typical Vf of 5W is 6.84V, the power drain from a cell will be:

(6.84V x 0.7A) / 80% = 6W
6W / 2cell = 3W/cell

According to Delivered Energy vs. Power Drain chart in the Duracell data sheet, one 123 cell can deliver about 1.8Wh. Thus, the regulated runtime will be:

1.8Wh / 3W = 0.6 hour = 36 min


[/ QUOTE ]
Your calculations are correct. You might do a bit better since the BB efficiency is likely a bit better at that input and output combination, possibly 85%.

 

[kj]

Thank you. I was thinking this configuration would run about an hour. That would be great if someone can compare these with the actual runtime plots.

 

[darkzero]

[ QUOTE ]
Doug S said:
I really doubt that you would see as much as 15 lm gain.
That 15 lm figure comes from people subtrating the datasheet typicals for 700mA from 1000mA.

[/ QUOTE ]

Yes, I figure the output gain wouldn't be 15lm from 300ma increase. Things don't always meet they're ratings. Since I don't dave a LuxII yet nor do I the R2K (untill tommorrow) I can't measure for myself. I just quote what is asumed by the LuxIII's specs rating. I've just kicked myself back to reality and accept what the equations state. Guess I just got caught up in the excitment or hype (whatever considered).

[ QUOTE ]
Doug S said:
Who knows? It would depend on the individual LEDs. It is entirely possible that are R bin 1W would be brighter than an S bin Lux III at the same drive current.

[/ QUOTE ]

Now back in the "real world", yes I should depend more on the binning factor but even though can mean nothing at times too. I was also thinking bigger and better which I know can't be trusted or is always true.

txs for making it seen. /ubbthreads/images/graemlins/thumbsup.gif

 

[Chop]

darkzero,
If you happen to decide to go with the 3W rather than the R2K, I'll take that R2K off of your hands. So far, all examples of R2K's that I've seen Kick Butt. I'm also guessing that the ones I've had had a low Vf regardless of their binning. I say this because I have yet to come across a Q3J that gives me longer runtimes than an R2K in similarly configured KL1's.

 

[Clifton Arnold]

Wayne @ EL just posted the bin codes for the stars he
received the codes posted are SYO the forth letter has not
been posted @ this time.