# 5761 w/ A123 - Soft Start Needed??



## RichS (Feb 23, 2008)

Ok, after my Mag85 spanked my 5761 with 6 Eneloops (and it was supposed to be my step-up mod), I've got a Black & Decker VPX pack sitting here and I'm ready harvest two A123 18650s from it. Hopefully these batteries will allow me to see the true potential of this bulb.

Before I put these in the light, is anyone running A123s in their 5761 without any kind of soft start and no insta flashing? The reason I ask is I spent the time to solder in a UTC (failed miserably), and was told that other's had my setup without a soft start and had not had a problem with insta flashing.

I would like to not mess with the UTC soft start if I don't have to, but I don't know if the bulb can handle the current in-rush of the A123s without it.

Thanks for your help!

-Rich


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## LuxLuthor (Feb 24, 2008)

*As I told you in the PM, with the link to the A123 Data profile showing the voltage* ???....so I don't see the point in using two A123 18650 cells here.

*The Eneloops have 1.45V hot x 6 = 8.7V

2 x Emoli will be about 4.15V hot x 2 = 8.3V

A123 IMMEDIATELY drop under load to 3.3V x 2 = 6.6V*​


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## Anglepoise (Feb 24, 2008)

Lux,
I am still a little confused. In your incan tests you report that a 5761 bulb 'flashed' at 7.9 volts. ( applied ) .

Then above we know that 6 freshly charged AA's will have a resting voltage of around 8.7 volts. So my thinking from this info is that the bulb should NOT flash as the applied voltage from the 6 AA's will sag immediately to ( in my case) to around 7 volts. I do not understand how RichS could 'flash' his 5761
with 6 AA's. Have I got this all wrong.
Your incan tests were done using a power supply that did not drop with load. 
Batteries on the other hand sag immediately.


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## LuxLuthor (Feb 24, 2008)

It depends on the NiMH cells you use, and how well they hold up at a certain Amp rating. You have to look at SilverFox battery testing at various Amp load rates. The Eneloops hold up their voltage at 5-6A, the Elite cells even better.

Remember also the initial startup is with a cold bulb filament. There is an initial millisecond voltage spike when you first turn on switch, then it reaches a stable voltage/current flow. It is that initial spike that often kills the bulb. That is why the NTC or AW's D Driver has the "soft starter" feature. They blunt the spike.


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## Anglepoise (Feb 24, 2008)

Got it. Thanks.

I am using Sanyo 2700's and I think I will need something a little more robust before experimenting with a 5761.


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## RichS (Feb 24, 2008)

Thanks again for the information LuxLuthor. I didn't mean to aggravate you, I sent you the PM after I posted this thread to get more specific information from you on your specific 5761 setup. The reason being that your "Most Powerful Mods" thread inspired me to do the 5761 since you had it listed as a brighter mod (two steps up from the Mag85). However, mine is noticeably dimmer regardless of what I try. I thought you might have some insight as to how you got yours to be noticeably brighter. 

Thanks again for taking the time to provide helpful information. I'll try to be less impatient next time before sending out a PM for info.



LuxLuthor said:


> *As I told you in the PM, with the link to the A123 Data profile showing the voltage* ???....so I don't see the point in using two A123 18650 cells here.
> *The Eneloops have 1.45V hot x 6 = 8.7V
> 
> 2 x Emoli will be about 4.15V hot x 2 = 8.3V
> ...


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## richied (Feb 24, 2008)

Hi,

let me weigh in here too. Just to add to the confusion, I pm'd Lux also recently with a very similar question...and my name is Rich too so...two diff folks here doing the same things 
I just built a 5761 based light in a mag 3c using 2xa123s.(lots of boring with a brake hone and removal of the cardboard around the cells needed) I am using AW's 3 stage pwm switch for a c body. 
The light is ok, but doesn't match my 3D based mag85 with Lux's eneloop packs. The trade off is the much nicer size/feel of the 3C mag.

The a123's do drop to nominal 3.3v/cell almost immediately. I picked them for the same reasons as you stated, based on Lux's testing, the emoli's will likely flash the bulb hot off the charger. 
I have been looking for a regulator to hard set the bulb voltage to 7.2-7.4 but have no joy as of yet for a c size solution. This would then allow the emoli's to be used.
I just found a 4C mag last week and am thinking about building a 3xemoli light with the 1185. This may be over the flash limit too, but using the low stage of the AW switch may be ok. The rub is the stages are set by quick taps of the on/off switch and it is easy to get to full power.
I'm trying to duplicate the performance of the 3D 1185 in a narrower host size like the C..and make it reliable enough to take camping/backpacking etc..and cheap to run(my m4 devastator surefire with an extended tailcap is 20% overdriven and very nice..but cost $10/hour to run with the CHEAPEST price for cr123s).

Rich D.


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## richied (Feb 24, 2008)

oh, a bit more info,

The runtimes and guestimated lumens with the mag3c, 5761 and 2 x a123's and AW's 3 stage switch are approximately as follows:

low- 1hr, 200 lumens, yellowish but useable.
med- 40min, 400 lumens, nice white
high - 23min 700 lumens, nice white

I'm rounding up a bit on these numbers and guestimating the lumens from Lux's tables, my calibrated eyeball comparison to my mag85 and over driven m4 and the formulas found elsewhere in the forums for lumens estimates.
The medium setting is putting out a noticeably larger hotspot on the tightest focus than the overdriven M4(225 (non overdriven) rated lumen bulb) but just slightly dimmer/yellower color. 
The high is as bright as the overdriven M4 with the larger hotspot. The lumen overdrive formula I think peg's the M4 at 475 or so lumens in this config.
By hotpot here ,I mean the apparent brightness seems the same as the M4 hotspot but maybe 25% larger, so more light.

For comparison, the 3D mag85 with Lux's eneloop pack does the following:

High- 43min, estimated 975 lumens( I round to 1000 )

It is significantly brighter than anything else mentioned here on high. I volunteer patrol some bike trails here at night a few times a week, and with the snow on the ground, high is way too bright with the mag85, low is just about right.

I didn't do runtimes on the lower settings.

RichD


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## LuxLuthor (Feb 24, 2008)

RichS....LOL! I did have RichieD and RichS swimming in my head, and didn't realize you posted this thread before the PM....so my bad, sorry. Bottom line is the 2 x A123's will be too low of voltage to be worth doing for the 5761.

The problem that you guys are facing is the 5761 while bright when optimzed, has a very narrow band of tolerable voltage. The ONLY regulated voltage driver that is currently in existence (& I have about a dozen of them) is the AWR Hot Driver...and it works extremely well.

The Lithium battery supplier, AW (no connection to user AWR) has come out with a C & D Mag Driver which offer soft starting, and multi-level output, but is not a REGULATED driver....meaning that you supply a battery with say....9V, and it gets regulated so only 7.2V is delivered to the bulb. 

AW is eventually planning on offering a regulated version that has been mentioned in this topic....but in the meantime, your only option is to try and get close to the optimal voltage for your bulb without flashing it....or try to scrounge up an AWR Hot Driver.


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## richied (Feb 24, 2008)

Too many folks named rich

Yup, I have the AW D and C 3 stage drivers and I know they are pwm only and not regulating the output peak voltage, just the duty cycle. I think he is only coming out with a d size regulated one at some point but no c size. I really want to make a C size light with mag85 output levels. If you ever want to sell one of those AWR regulated drivers...send me a PM. If I was really motivated, I should dust off my EE degree and design one.

richD


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## RichS (Feb 24, 2008)

Thanks Lux, this clears it up for me. So to make amends, how's about you sell me one of those regulated drivers! 

Kidding, but seriously, what'll you take for one?? Everyone's got a price...



On another 5761 note, I just got back from my local BatteriesPlus store, and bought a couple packs of 2700Mah Powerex NiMH batteries. I read around a little, and from what I've read it seems this battery should be better at handling the high draw of the 5761 than my Eneloops. Hopefully they will have a little less sag and deliver a little more voltage to the bulb. Can anyone confirm this? If there really isn't any advantage to using the Powerex over my Eneloops, I'll just take them back and save $30. I would have gone with the Elite NiMH, but I'm going out of town and didn't have time to order online. This was the best I could find from a local store.

Also, I read in Lux's post that some batteries need to be conditioned. Does anyone know if the Powerex batteries need conditioned? Does that just entail running them all the way down first and then fully charging?

-Rich



LuxLuthor said:


> RichS....LOL! I did have RichieD and RichS swimming in my head, and didn't realize you posted this thread before the PM....so my bad, sorry. Bottom line is the 2 x A123's will be too low of voltage to be worth doing for the 5761.
> 
> The problem that you guys are facing is the 5761 while bright when optimzed, has a very narrow band of tolerable voltage. The ONLY regulated voltage driver that is currently in existence (& I have about a dozen of them) is the AWR Hot Driver...and it works extremely well.
> 
> ...


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## LuxLuthor (Feb 24, 2008)

Remember when I said you have to look at SilverFox's battery testing thread? It is listed in the pinned topic in battery section. About 2/3 the way down that NiMH Shootout topic you will see the PowerEx 2500 compared to the Eneloop. The 2700 would not be as good regarding Amp rate as the 2500, so neither are as good as the Eneloops for this purpose. Look at the 5A and 6A curves to see how well the voltage holds up. Also go look at the Elite 1700 AA cells graph at cheapbatterypacks.com

I could spell it out in really easy links and copying all the graphs, but I believe it is useful to teach people how to fish, so they will remember next time.

After you look at the graphs, if you don't understand what they are showing, then let me know here and I will be happy to explain them....but go look at them first.


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## RichS (Feb 24, 2008)

LuxLuthor said:


> Remember when I said you have to look at SilverFox's battery testing thread? It is listed in the pinned topic in battery section. About 2/3 the way down that NiMH Shootout topic you will see the PowerEx 2500 compared to the Eneloop. The 2700 would not be as good regarding Amp rate as the 2500, so neither are as good as the Eneloops for this purpose. Look at the 5A and 6A curves to see how well the voltage holds up. Also go look at the Elite 1700 AA cells graph at cheapbatterypacks.com
> 
> I could spell it out in really easy links and copying all the graphs, but I believe it is useful to teach people how to fish, so they will remember next time.
> 
> After you look at the graphs, if you don't understand what they are showing, then let me know here and I will be happy to explain them....but go look at them first.



Thanks for saving me $30 Lux. To be honest, I did look at that battery thread earlier when you pointed me to it, and I did see the Powerex in there not performing so well. But I also saw that the thread was 3 years old. That, combined with the fact that I have seen major modders (NL) mentioning using Powerex in more recent posts made me think that maybe they have done something to improve their batteries in this application. So much for my logic..

It seems I also just made the connection that typically the higher the runtime (mah) a battery has, the worse the amp rate. It seems the best is the 1700 mah Elites, the 2000 mah Eneloops are pretty good too, and the 2700 mah Powerex have poor amp rates. Not sure why this is the case, but it's just another piece in the puzzle for me.

Thanks again Lux! I'll be ordering some Elites (if I can find them in stock somewhere - cheapbatterypacks.com is out) and see if these will tip the scales in favor of my 5761 over the Mag85. If not, then I may have to try the resistance fix on the stock switch.


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## starburst (Feb 24, 2008)

If you really want to use your A123 cell's with the
5761 you will need to hunt down and strangle to 
death any resistance you can find with copper,the
tailcap spring and switch fix should help alot. with
battery charge terminated at 3.6 volt's the 5761
should be safe from instaflasing. Not sure how long
the 18650 size will run.


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## LuxLuthor (Feb 25, 2008)

RichS, good job checking that out. Even though some of the SilverFox charts are old, their performance is valid for that battery model. The higher mAh is a _*supposedly *_a measure of the total stored energy of the cell. 

Most the time, when they put more energy capacity, it is at the expense of not holding voltage under higher Amp loads....which is fine for most consumer electronics (mp3 players, TV remote control, etc.). There are technical explanations (layer thicknesses, type of electrolyte mixtures, internal resistance, etc.) for why this happens....but many manufacturers bank on people not knowing how to find out the real performance of batteries (either the REAL mAh or voltage sag under loads), resulting in advertised mAh rating being falsely inflated.

PowerEx (MaHa) is one of the more highly respected brand names in terms of delivering the mAh capacity that is stated....but as you now have seen, holding voltage in higher mAh cells under load is an intentional tradeoff.

It is rare that you need to get the higher Amp output that the Elite cells provide, so their product is really a "niche" high current application battery....and I would be surprised if they continue making the Elite AA size for much longer. Most RC users have moved to the LiPo packs, and the newer Emoli/A123 Lithium cells.

*Starburst*, again the A123 cells drop to 3.3V under load *immediately*....so it doesn't matter if you charge them up to 4 Volts. Two of these cells will ONLY provide 6.6V, and there will be some decrease even if you remove most sources of resistance that you can in the light. Ohm's Law is Ohm's Law, and every part of the light has some resistance unless you direct solder thick wires from cells to bulb.

I would say on a practical basis, *two A123 cells will end up delivering more like 6 (or less) volts to the bulb* for most setups. Unfortunately, 3 x A123 will be too much voltage for the 5761. This is why 2 x Emoli at 4.15 to 4.2V (hot) is a better choice for this bulb.


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## Anglepoise (Feb 25, 2008)

After reading all about this, I come to the conclusion that we need to get the resistance as low as possible in whatever switch and tail cap spring we use.

And the only way to measure this is with a low ohms meter.

These are very expensive to buy but after a little research I have found what looks to be a viable DIY solution for under $10.00. 

I originally tried to build a more sophisticated one, but my electronic skills were not up to the task. This simple one ,powered by a 9 volt battery was easy and works very well indeed. 

I finished it last night ,so have not yet started to mod my switch (End cap spring I did last week ) but will take measurements as I go along and see how much resistance I can remove via 'hard wiring' the Mag switch.
See link below for full instructions and pics

http://users.tpg.com.au/pschamb/lom.html


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## richied (Feb 25, 2008)

Lux,

what do you think about these two setups: mag 3c, 2 emoli 26700a's, 5761 bulb and AW 3 stage vs mag4c (extension needed?),3 emoli 26700a's, 1185 bulb and AW 3 stage? 
On paper I think the 1185 setup should run longer because of the lower current draw. I think both setups will flash the bulb at full power but am not sure and should be similar in output based on your tables. I am going to aquire some emolis soon to experiment.
Do you know if the emoli's are slightly narrower than the A123s? I had to do a lot of brake hone boring with the 3c and remove cardboard and retape the a123s to get them to fit. I'm not comfortable with the setup, I think the a123's could possible melt the mag body if they should ever short thru the tape!

richD


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## LuxLuthor (Feb 25, 2008)

Anglepoise, thanks for that link. I remember seeing another post recently that I think linked over to RC Groups forum but seeing how involved that looks, sometimes I think of just buying one.

Realistically, you can start out assuming that a stock Maglite Switch has about 200 mOhms, and get close to the ideal voltage/current for a bulb, taking that into account...and get a couple extra bulbs....if you flashed one at a particular hot voltage, you need to either use a NTC to blunt the initial millisec voltage spike and/or use a bit of resistance in your setup.

It is not always best to reduce resistance as you suggest....as the scenario where your battery voltage is close to the flash point of the bulb, lowering the resistance will push it over the edge.


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## Fulgeo (Feb 25, 2008)

Have a Mag85 with FM 9 cell battery holder with Sanyo 2700. I also have a Mag61 with 2 A123 cells. Both using FM bi-pin holders. Have not done resistance mods yet. Just got my Progold today BTW. Anyhow when I bounce the two lights off the ceiling the Mag85 seems to beat the Mag61 but outside on distant targets I might give the edge to the Mag61. The 5761 bulb generates a fatter more usable beam. Everything else is equal on these two flashlights including FM reflectors and such. Considering that my Mag61 is a 2D unlike the 3D Mag85 methinks I will give the nod to the Mag61. Heading outside right now with both flashlights to give this another look.


Your wattage may differ.


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## LuxLuthor (Feb 26, 2008)

Fulgeo said:


> Have a Mag85 with FM 9 cell battery holder with Sanyo 2700. I also have a Mag61 with 2 A123 cells. Both using FM bi-pin holders. Have not done resistance mods yet. Just got my Progold today BTW. Anyhow when I bounce the two lights off the ceiling the Mag85 seems to beat the Mag61 but outside on distant targets I might give the edge to the Mag61. The 5761 bulb generates a fatter more usable beam. Everything else is equal on these two flashlights including FM reflectors and such. Considering that my Mag61 is a 2D unlike the 3D Mag85 methinks I will give the nod to the Mag61. Heading outside right now with both flashlights to give this another look.
> 
> Your wattage may differ.



Definitely the Philips 5761 is brighter than the 1185 light if overdriven enough. You can see my measurements of the two bulbs at various voltage levels here....the problem with using 2 x A123 cells is you won't get the voltage up high enough to maximize what the 5761 can really do.


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## Fulgeo (Feb 26, 2008)

Hey LuxLuthor,

Wanted to bounce another observation off you. I have 16 of the Sanyo 2700s and 16 of the Sanyo Eneloops AAs. I like the 2700 but love the Eneloops. One thing thou about the Eneloops. They definitely hold their charge better but I have noticed that they hold their voltage better also. Have you noticed that after a few days the Eneloops still have a relatively higher voltage than the 2700?


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## cat (Feb 26, 2008)

Fulgeo said:


> The 5761 bulb generates a fatter more usable beam.



That is basically why Northern Lights likes the 5761. 



richied said:


> mag 3c, 2 emoli 26700a's, 5761 bulb and AW 3 stage ...



Northern Lights (and jimjones3630, I think) went to 3C to use 2 x emoli and 2 x A123, with the NTC soft-start to prevent instaflashing. There're a lot of posts by them about it; Northern Lights has given a list of links to the main ones in some of his posts, so they're easy to find. 



richied said:


> Do you know if the emoli's are slightly narrower than the A123s? I had to do a lot of brake hone boring with the 3c and remove cardboard and retape the a123s to get them to fit. I'm not comfortable with the setup, I think the a123's could possible melt the mag body if they should ever short thru the tape!



They mustn't short through the tape; the tape must stay intact. (Should be Kapton tape. http://www.kaptontape.com for explanation.) Also see Northern Lights posts re using 10A blade fuse in tailcap. 

Here are some dimension measurements by petrev (slightly edited by me): 

--------------------------------------------------
cpf Petrev diameter measurements (mm)
--------------------------------------------------

Mag D ID 33.

old Mag C ID 26.30 (no C in serial number)
new Mag C ID 26.24

standard C alkaline (Duracell)
26.20
AW C Li-on 25.62

A123 26650 26.91 cardboard sleeve (too big for Mag C)
A123 26650 25.91 bare
A123 26650 25.99 parcel tape (brown) fits
A123 26650 26.21 parcel tape (multi-layer) fits very snugly


Emoli 26700 26.60 cardboard sleeve (too big for Mag C)

Emoli 26700 26.10 bare
Emoli 26700 26.24 parcel tape (brown) fits old C snugly
fits new C exactly / just too big (depending on tolerances?) 

standard D alkaline (Duracell)
Diameter 34.2mm
Length 61.5mm

standard C alkaline (Duracell)
Diameter 26.2mm
Length 50.0mm


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## richied (Feb 26, 2008)

cat,

thanks for the battery dimension info and links, especially the kapton tape...been trying to find some, was going to wait for the MIT flea market here in MA to start again in April...lots of parts and hard to find supplies like that. Youdoit electronics said they didn't stock any( a local good electronics store in Needham MA). 
I will search for the threads you mentioned. Looks like the emoli's will be a pain to fit..just slightly wider than the a123's which took hours of honing to get them to fit with just thin plastic electrical tape. I don't like the use of this tape since it could rip easy and short the cell. will definitely order a roll of the kapton.
Anyone have suggestions on brake honing techniques to open up a mag body? I found that I had to use some oil to keep the aluminum from galling, I'm not sure if this is the best way to do this? Lower rpm better?....i'm using an old electric drill with one speed only and it may be too fast.

richD


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## LuxLuthor (Feb 26, 2008)

richied said:


> cat,
> 
> thanks for the battery dimension info and links, especially the kapton tape...been trying to find some, was going to wait for the MIT flea market here in MA to start again in April...lots of parts and hard to find supplies like that. Youdoit electronics said they didn't stock any( a local good electronics store in Needham MA).
> I will search for the threads you mentioned. Looks like the emoli's will be a pain to fit..just slightly wider than the a123's which took hours of honing to get them to fit with just thin plastic electrical tape. I don't like the use of this tape since it could rip easy and short the cell. will definitely order a roll of the kapton.
> ...



Man we are covering a lot of bases in this thread! Here is a description of Kapton. The 1 mil thick is best, even though the adhesive layer adds a bit to that making it not truly 1 mil thick. This site has 50% discount for 1 roll samples.

McMaster-Carr is another place to find it. The reasons people promote Kapton is its heat resistance, electrical insulation, and resists solvents. 

The simple "packing" tape adhesion layer melts at low temps typically seen in our hotwires, resulting in a gooey mess...and easily transfers to the inside of the tube. Yuck!

Now regarding the brake honing. Use the coarser (larger size) tri-stone #275 at top here. I think it is important to use a portable, reversible drill that is not real fast like many electrics. I also use my portable drill in the kitchen sink with a slow trickle of cold water. It keeps the aluminum dust out of the air, washes away the slurry, and keeps it cool. Amazingly, the stones and KD Hone are not affected by the water....and it helps keep the stone from clogging up.


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## Northern Lights (Feb 27, 2008)

Too long of a thread to read it all so I will just answer the first post. A 3C host with two A123 cells will run a 5761 without soft start just fine. I have one that I use the heck out of. Vbulb is 9.9 volts, yes, because they are flat discharge you get higher than the rated nominal voltage. 9.9Vbulb is good with a 5761 as almost if not all will run on that without soft start, above that as you approach 7.1 you will find bulbs that will flash even with soft start. 
With the 3C host to get the 9.9 Volts at the bulb you need to do tail cap and switch mods to reduce the resitance.
There is plentay of room to put in a charging jack too. A123 will charge just fine in series with the right charger. 
Search 5761 key work. Jim Jones and I have posted a bunch about this as well as our bud, Lux.
tail cap and switch mods with jack






3C host next to a 2c which has an AW spacer


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## Northern Lights (Feb 28, 2008)

LuxLuthor said:


> *As I told you in the PM, with the link to the A123 Data profile showing the voltage* ???....so I don't see the point in using two A123 18650 cells here.
> 
> *The Eneloops have 1.45V hot x 6 = 8.7V*​
> 
> ...


 
Oh, well, I had to speed read through this thread, having messed with most of the stuff surrounding the emolis, A123 and 5761. I tacked onto Lux's post because it is a good intorduction and starting place. 

Here are some of my observations:
In more than one light with two A123 26650 the 5761 do not dop to the expected 6.6 or less Vbulb but have a flat curve down from 6.9V at the bulb. It does not seem to be enough of a load from this bulb to do to drop to the expected nominal voltage. The voltage stays up longer than the Emoli too, simple side by side testing shows after several runs to bring the battery down, run tests, that after a few minutes the A123 5761 runs brighter. Usually when you turn the lights on together the emoli is brighter at onset but dims faster. Running the various 64430 we ran on 3 of the A123 cells also demonstrated voltages slightly higher than the expectd 9.9 vbulb too.

The emolis also work great but you need soft start and some control because the overhead voltage, Vbulb is more like 7.32 volts on direct drive emoli. Vbulb 7.1 is about all that 5761 bulb can handle, I was getting some flashed bulbs at 7.3 Vbulb. The NTC posted now in a zillion posts worked good most of the time but recently I got a few that were way on the end of the factory specs for tolerance and were delivering too much residual resitance and were cutting the end voltage too much. I need to get some more like the first bunch. They dropped voltages by 0.3 volts on the 5761, they added 0.06 ohms resistance when in equilibrium.

Emoli and A123 need to be rewrapped in shrink or Kapton, forget the cardboard tube. 

I take Vbulb readings with a meter hooke parallel righ into the bulb pins in a working light.


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## LuxLuthor (Feb 28, 2008)

Northern Lights said:


> Too long of a thread to read it all so I will just answer the first post. A 3C host with *two A123 cells* will run a 5761 without soft start just fine. I have one that I use the heck out of. *Vbulb is 9.9 volts*, yes, because they are flat discharge you get higher than the rated nominal voltage. *9.9Vbulb is good with a 5761* as almost if not all will run on that without soft start, above that as you approach 7.1 you will find bulbs that will flash even with soft start....



*NL, with much respect*, if you are saying that each A123 cell is charging up to 4.95V and holding that to run the 5761 bulb, I must disagree. :kiss: 

"There ain't no way" the A123 have that kind of voltage capability. There is also no way that the 5761's I have used will hold up to that high (9.9V) voltage without flashing. With two Emoli it is also not critical to get rid of as much resistance, since they start out at 8.3V, and you want some blunting resistance to remain in the light....in addition to the NTC. My ideal setup is using them in an AWR Hotdriver 2D Mag.

I was talking about 2 x Emoli vs. 2 x A123 in the larger 26mm sizes. If you are using the used/abused Emoli cells that have been sold by another member here at CPF, I'm not using any of those cells. I had to throw half of them away on arrival due to signficant damage to shells, and the other half were not close to the same performance scale of the new Emoli that I gotten elsewhere. It became apparent to me that these were end of life Emoli that someone was dumping on the EBay market, and I would not draw any performance conclusions on those cells.

The quality Emoli cells hold their voltage from 4.15 down to 3.5V, which is about the level when I stop using them and recharge. In my experience they delivered a higher voltage and brighter 5761 than the A123, until the Emoli got down to end of capacity. Given the hassle of the A123 lower voltage & unique charging protocol (to maximize cell life), I have almost entirely switched over to Emoli. 

It may be true that the overcharged A123 start out at 3.5V for a very brief period of time before dropping towards their default 3.3V level when subjected to only a 5 to 6A drain rate, but clearly the objective testing profiles do not support the notion of their staying at 3.5V at any time under load as shown on page 3, (use interpolated curve closer to the black 10A graphed line as related to the 5.5 Amps used by 5761 bulb.


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## Fulgeo (Feb 28, 2008)

I think NL meant to say 2xA123 cells deliver 6.6volts to the bulb not 9.9volts. He just made a little typo. The point he was trying to make was that the 5761 runs bright with 6.6volts with little to no chance of flashing the bulb. The A123 cells deliver and do not get crushed by the 5 Amp load of the 5761. Anyway I will shutup now and let the big boys talk.


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## Northern Lights (Feb 28, 2008)

Northern Lights said:


> Too long of a thread to read it all so I will just answer the first post. A 3C host with two A123 cells will run a 5761 without soft start just fine. I have one that I use the heck out of. Vbulb is 9.9 volts, yes, because they are flat discharge you get higher than the rated nominal voltage. 9.9Vbulb is good with a 5761 as almost if not all will run on that without soft start, above that as you approach 7.1 you will find bulbs that will flash even with soft start.
> With the 3C host to get the 9.9 Volts at the bulb you need to do tail cap and switch mods to reduce the resitance.
> There is plentay of room to put in a charging jack too. A123 will charge just fine in series with the right charger.
> Search 5761 key work. Jim Jones and I have posted a bunch about this as well as our bud, Lux.
> ...


2x A123 on that light is Vbulb 6.9. Yep, a typo. What surprised me and I attribute it to the fact the battery has one of the flatest if not the flatest discharge curves out there is that at the draw of the 5761 it starts out at 6.9 volts at the bulb after that first moment of initial drop in voltage. I was expecting 6.6vbulb but it has always been higher than that with several sets of cannibalized batteries. 

The emoli start out higher and the residual resitance from an NTC that is at 0.06 ohms when use will drop the voltage 0.3 volts and also give 6.9 at the bulb. I find that about half way through the battery charge when you turn on the Emoli and the A123 in a side by side the Emoli appears a little brighter but will dim belong the A123 if you allow the run to continue for a few minutes. Cool the lights and you can repeat that a few more cycles. In the lights I did test side by side when the bulb took a noticalbe dimming and off color I called it quits, the emoli went out before the A123 but this was so close I would not bet on it for every set of batteries out there.

I like the emoli idea too and have been switching when I make one here or there. But I now find the NTCs may not have tolerances tight enough to depend on that 0.06 Ohms at stasis, I have two that ar at 0.24 ohms or 4x the expected resistance. Time to look at available alternatives.

Too late, too tired and I was also thinking about the 64430 where I try to keep it at 9.9 from 3x A123 and these are the 26650 cells, 26mm diameter, 65mm long, 0 for round. 

I will post here a discharge chart for the A123 that is very interesting a little later, maybe this evening.
Gee Whis guys!! while I was trying to edit this two other posters headed into the fray and I got cut out before I finished, Well, here it is, voltage v. minutes the grey and red line are the A123 on the 64430, you can extrapolate and see what I mean about it holding 6.9 Vbulb on the 5761, these grapsh were done by a fellow that was looking for a power solution, they are not the best possible condition factory authorized published data, this is what really happened, at least on this guys bench.




quote from the guy who did the graphs for me:

that is quite likely the best direct-drive solution of any flashlight 
of ever...

this is the 64430 light comparing the hotdriver vs NTC direct-drive 
solutions.. as always i used 30mohm ckt resistance and for the NTC i 
used 45 mohm.. half way between 60mohm for 5A and 30mohm for 10A...

the solid lines are the hotdriver solution and the dotdash lines are 
the NTC DD solution..

there is a bit of a spike in the beginning.. it should be not a 
problem, the lamp re-rates to about 6 hrs even at the 'spike' 
voltage.. and without the NTC i'd be concerned.. non-issue with the 
NTC..


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## jimjones3630 (Feb 28, 2008)

This thread has more tangents and rabbit holes than a Arkansas deer trail. A lot of info and must admit only ready a few posts.

A123 2200 mah cells out of Dewalt 36v battery paks 2 of them do not need a NTC or soft start to power up 5761. I specify these batteries as I have noted often confusion with other batteries. 

Rich, you are using 18650 A123 and can that is like comparing apples to oranges. all of NL and my research with A123 cells has been with the 2200mah cells out of Dewalt 36v paks. 

What we do here is push bulbs, batteries, circuits, and human patience to the wall. So I consider A123 cells from any other source a different battery and indeed that is true. Even if Dewalt 36v battery paks where made at another plant along with the plant in Canada I would redo the work up to test those batteries and not make the mistake of assuming they have the same level of performance. 

NL has said all there is to say I can only say 1+, me to. these A123 batteries are the flattest discharging cells or should say flatter than Emoli cells and flatter than any cells I know. 



RichS said:


> Ok, after my Mag85 spanked my 5761 with 6 Eneloops (and it was supposed to be my step-up mod), I've got a Black & Decker VPX pack sitting here and I'm ready harvest two A123 18650s from it. Hopefully these batteries will allow me to see the true potential of this bulb.
> 
> Before I put these in the light, is anyone running A123s in their 5761 without any kind of soft start and no insta flashing? The reason I ask is I spent the time to solder in a UTC (failed miserably), and was told that other's had my setup without a soft start and had not had a problem with insta flashing.
> 
> ...


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## richied (Feb 28, 2008)

*Good Golly...Emoli!*

I ordered a new Milwaukee pack for $100 on ebay yesterday. I think what I will try, as another poster did in CPF, forgot his name, is make my 4 c into a mag85 with the emoli's. This should run almost an hour on full with the AW 3 stage switch and give a nice sized light. I can also then compare side by side with my 3C a123 based 5761 light...and try the emolis in that too. I will report back in a week or so when I get this all together.

richD

p.s. I only get an open circuit voltage of 6.6v at the bulb socket with my 3c a123. The cells seem pretty consistent at 3.3v each shortly after charging. I charge them with a Trtiton Jr, not exactly designed for them..either at 4.2v/cell or now, 7.2v for 2 in series. This is the charger nominal setting...it varies a bit I think during the charge cycle. So far no issues and the run times I posted earlier with with this setup. I'm not set up to measure Vbulb under load..you guys using a shunt resistor in parallel or something? I think I saw that in here someplace.


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## richied (Feb 28, 2008)

*Good Golly...Emoli!*

Double post


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## richied (Feb 28, 2008)

*Good Golly...Emoli!*

Treble post


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## Northern Lights (Feb 28, 2008)

*Re: Good Golly...Emoli!*

One thing I have seen before, is people saying that the 1185 was brighter than the 5761 but have them say AH HA! after this explanation.

It can look that way and sure at the dead center that could be true! Lumens is the total light out put, the 5761 will put out more light than an 1185, if it doesn't there is something wrong with the build, now then with the science and proven technology that is no longer a varialbe.

Lux readings, (some think that is the fortune telling our friend L. Luthor does on the side) is the intensity of light at a given point, similiar to candle power designations. Usually taken dead center.

The beam patterns of the two bulbs are very different. The 1185 concentrates its light into a small hot spot. Accross the room or drive, against a wall, yep, that spot may be brighter. The 5761 throws as far but has a hot spot about twice the diameter of the 1185. There is only 50-90 lumens difference, depending on your variables between the two. You are spreading that light out over twice the area with a 5761. The total beam width is a function of the reflector, same reflector for both then only the hot spot is the issue of measurement.

Think of it this way, a hose spraying water. The amount of water, gallons/minute is equated to Lumens. The pressure is where the lumens are consentrated. Open the nozzle to a wide spray and the pressure in any area is reduced, dimmer, than making a tight stream. Same amount of water (lumens) but the feel of pressure (brightness) is different.

Yes, an 1185 can look brighter and probably is in the dead center. If you need a bright concentrated spot between these bulbs the 1185 maybe it. If you need a lot of light over a broader area or a more general use torch, the 5761 is hard to beat. 

Stand in a road or field where you can compare objects and shadows out to the side for a good distance. You will see where all those little lumens are going. To light my path, the 5761 does a better job.


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## richied (Feb 28, 2008)

hmmm...sorry for the triple post...not sure how that happened

double hmmmm...5761 vs 1185...you know I'm getting exactly the opposite...my 3D 1185 seems to have a larger somewhat oval beam..roughly twice the size of the 5761. At night in a dark area outside, and inside off a white wall, they seem about the same color temperature on full( I have both an AW C and D 3 stage). The 5761 has a nice round beam. Probably the reflectors..they are different..forget which..medium OP and one other(not smooth) I don't recall.

I am using a123 26650 developer cells.

richD


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## Northern Lights (Feb 28, 2008)

*Re: Good Golly...Emoli!*



richied said:


> p.s. I only get an open circuit voltage of 6.6v at the bulb socket with my 3c a123. The cells seem pretty consistent at 3.3v each shortly after charging. I charge them with a Trtiton Jr, not exactly designed for them..either at 4.2v/cell or now, 7.2v for 2 in series. This is the charger nominal setting...it varies a bit I think during the charge cycle. So far no issues and the run times I posted earlier with with this setup. I'm not set up to measure Vbulb under load..you guys using a shunt resistor in parallel or something? I think I saw that in here someplace.


 
On a light if you take voltage readings of the circuit along the circuit the Vbat should be the same everywhere. You did not say how you are taking the Vbulb, I would like to know what you are getting. 
One thing to do is to understand what the resistance of your switch and tail cap configurations are. Measure the resistance accross each seperately. Take the bulb out and jump the socket with copper wire to remove its resistance. Some meters do not zero and you have to Tare the reading by subtracting the meter resitance from you meausurements. 

Volts at the bulb is a blinding situation. Pull the bulb out a little so you can get to the pins. Put a piece of thin copper wire around each and hook to your meter. The meter is in parallel circuit now. Turn on the light an see what the reading is. That is Vbulb.

You said you are getting open circiuit readings at 6.6 volts, if you mean you are taking voltage Vbattery potential at that point I see a problem. That is if I understand what you are saying, I have mistaken things before, that is how JJ and I met!
But your batteries open circuit, no load off the charger should read about 3.6 volts, you should have 7.2 volts there. The moment you turn on the light the load pulls it down. If your open circuit is less than what you read at the batteries I would start looking for a poor connection or high resistance.


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## Northern Lights (Feb 28, 2008)

richied said:


> hmmm...sorry for the triple post...not sure how that happened
> 
> double hmmmm...5761 vs 1185...you know I'm getting exactly the opposite...my 3D 1185 seems to have a larger somewhat oval beam..roughly twice the size of the 5761. At night in a dark area outside, and inside off a white wall, they seem about the same color temperature on full( I have both an AW C and D 3 stage). The 5761 has a nice round beam. Probably the reflectors..they are different..forget which..medium OP and one other(not smooth) I don't recall.
> 
> ...


Yep, reflectors change things, got to be equivalent.
I prefer and for me only use smooth reflectors because they reflect the most light, as you add texture you loose light. 
But to tone down the artifacts I use Armour Etch and frost the bulbs. I put it on with a cotton tip up to a point, bottom to just past the filament. The 5761s take two treatments of 35 minutes each. After the tiemis up I wash with running water, soap and a brush then finish with alcohol dabbing it off with tissue. Now that leaves the top of the bulb clear, because no shadows come from above the filament, it is the hardware below the filament that casts the artifacts and frost uses lumens whether on the reflector or glass. I squeak every last one of those guys I can out of the build.
FM reflectors and MagCharger reflectors throw a bit more than Litho 123 reflectors. Kai reflectors look like FM reflectors, I have them but have not tested them yet.
The MagCharger reflector with the 5761 can actually cast light and shadow out to over 2000 feet. The litho reflector has a very good flood effect still with 80 yards or more of very useable light for my purposes.


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## richied (Feb 28, 2008)

I will re-measure tomorrow, but what I have done is use my DVM probes inserted into the bipin bulb socket..and measure about 6.6v with the AW switch cycled to high. The batteires each measure about 3.3v after being fully charged and sitting for a while.

RichD


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## LuxLuthor (Feb 28, 2008)

The reason I did the destructive testing the way I did...after much thinking, and discussion with AWR who put together the Hotrater spreadsheet....is there is no easy and reliable way to objectively test "out the front" lumen output of our lights. There is variation based on the brand, surface texture, bulb opening size, bulb focus position of the reflector. The battery brand, quality, age, state of charge, resistance of light components are hard to control. Then the size, shape, age, filament style, color of the bulb, variations in beam hotspot, smoothness, and light meter placement gives another set of variables....making objectivity nearly impossible.

I decided to treat bulbs as a point light source, and used the tube and a black background to eliminate any scatter reflections. Obviously it does not take into account the effect of bulb color on your perception, or size of hotspot/spill on practical useage. It is still useful assuming you have a reasonably similar reflector catching roughly the same overall amount of reflected light, and at least it is objective. Short of someone buying a $15,000 calibrated integrating sphere, and testing at multiple overdrive voltages for each bulb, at least twice to verify consistency....I don't see another way to compare bulbs.

Then there is the whole other issue of the dropping lux/lumen output at a particular overdrive voltage....which follows a whole other curve with the age of the bulb.


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## jimjones3630 (Feb 29, 2008)

Is that the 18650s?

A123 2300mah fully charged I get a reading of 3.6v even after sitting awhile. 



richied said:


> I will re-measure tomorrow, but what I have done is use my DVM probes inserted into the bipin bulb socket..and measure about 6.6v with the AW switch cycled to high. The batteires each measure about 3.3v after being fully charged and sitting for a while.
> 
> RichD


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## Northern Lights (Feb 29, 2008)

jimjones3630 said:


> Is that the 18650s?
> 
> A123 2300mah fully charged I get a reading of 3.6v even after sitting awhile.


so do I and they do not drop to 3.3 under 5 amp load on two cells immediately either, that is why I get 6.9 Vbulb when I first turn on the 5761.


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## Fulgeo (Feb 29, 2008)

LuxLuthor said:


> The reason I did the destructive testing the way I did...after much thinking, and discussion with AWR who put together the Hotrater spreadsheet....is there is no easy and reliable way to objectively test "out the front" lumen output of our lights. There is variation based on the brand, surface texture, bulb opening size, bulb focus position of the reflector. The battery brand, quality, age, state of charge, resistance of light components are hard to control. Then the size, shape, age, filament style, color of the bulb, variations in beam hotspot, smoothness, and light meter placement gives another set of variables....making objectivity nearly impossible.
> 
> I decided to treat bulbs as a point light source, and used the tube and a black background to eliminate any scatter reflections. Obviously it does not take into account the effect of bulb color on your perception, or size of hotspot/spill on practical useage. It is still useful assuming you have a reasonably similar reflector catching roughly the same overall amount of reflected light, and at least it is objective. Short of someone buying a $15,000 calibrated integrating sphere, and testing at multiple overdrive voltages for each bulb, at least twice to verify consistency....I don't see another way to compare bulbs.
> 
> Then there is the whole other issue of the dropping lux/lumen output at a particular overdrive voltage....which follows a whole other curve with the age of the bulb.




Your destructive testing posts are greatly appreciated. Its a thread I check daily. I have printed out the spreadsheets and from time to time with calculator in hand plug in A123 and Emoli cell combinations and compare lumens, runtime, heat, bulb life etc.... You have posted your testing methods and I think it is understood that sometimes it goes beyond science and becomes an art form. Have purchased 8 Osrams bulbs based on it. Just wanted to say thanks for the continuing effort.:bow:

Ok enough butt kissing, just keep that bulb data coming in!


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## jimjones3630 (Feb 29, 2008)

Seems clear to me different batteries do not perform as well. A123 2300mah cells from 36v Dewalt paks and Emoli 2670mah cells from 28v Milwaukee paks are hard to beat.



Northern Lights said:


> so do I and they do not drop to 3.3 under 5 amp load on two cells immediately either, that is why I get 6.9 Vbulb when I first turn on the 5761.


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## LuxLuthor (Mar 1, 2008)

Northern Lights said:


> I like the emoli idea too and have been switching when I make one here or there. But I now find the NTCs may not have tolerances tight enough to depend on that 0.06 Ohms at stasis, I have two that ar at 0.24 ohms or 4x the expected resistance. Time to look at available alternatives.
> 
> Too late, too tired and I was also thinking about the 64430 where I try to keep it at 9.9 from 3x A123 and these are the 26650 cells, 26mm diameter, 65mm long, 0 for round.
> 
> ...



NL, I have looked at AWR's graph :duh2: that you posted several times, and it is still not clear to me what you trying to show with it....in part because he put all the other test parameter lines for his HotDriver on the same graph, and the lines are hard to figure out. :duh2: oo:

Correct me if I am not reading this correctly. This is a graph of 3 x 2300mAh A123 in series (from Dewalt pack), running one of the three versions of the 64430 bulbs (Osram, Tungsram, TopBulb) that we have seen. The green current line appears to be exactly 7.5A, assuming that is his HotDriver plot.

However, my question is how you are saying this plot verifies 3.6V under load is delivered per A123 cell, which can then be extrapolated over to the 2 x A123 for 5761 bulb setup? 

If that were true, the gray Vbat line (I only see a single, light gray line which he says is Vbat) would start at 10.8V, then when circuit is completed, the Vlamp red dotted line shown dipping below the 9.0V line at 2 mins run time, would also be higher.

Also what are you using to measure resistance tolerances down to 0.06 Ohms, & the 30/45/60 mOhms that you mentioned with the NTC?


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## richied (Mar 1, 2008)

an update...

The emoli's arrived yesterday, brand new Milwaukee pack. I also found some kapton tape at youdoit electronics after all. Today I bored out the 4C(thanks for the tip on the cold running water Lux, that made it go a lot faster!) and moved my c size AW switch from the 3c into it. 
Some initial observations, I ran 3 of the emoli's with an 1185 bulb. The cells charged to about 4v each. The light ran well, and by eyeball, seemed to match the 3D/eneloop powered mag85 I have. 
But..it only ran bright for about 30 minutes. I did a run down test by letting it run on hi for 15 mins, then maybe 5 minutes or so of shut off/cool down(too hot to touch the head), then restart the stop watch and run again. After 30 minutes, it got fairly yellow on hi and continued to run dim/yellow for about 20 minutes or so before fading out. If I recall the eneloops ran brighter for the 43 minutes but next time I'll run them side by side on a fresh charge.
The other thing I found is that the emoli's take a very long time to charge compared to the A123's. I set the charger to 5000mA and 3.7v LiPO. They don't take a lot of current, maybe 1.7A initially then down to 600-700mA for up to 2 hours..the charger quits and says over time or something at 2 hours. I then charged 2 batteries in series set to 7.2v and they charged for another hour before the charger declared them full this time. The charger is putting out 4.2 v(single charge) but I only am getting 4.0v at the batteries so I need to look into my charging lead setup. Still I expected better charging performance.
The a123's if charged 2 in series come right up in about 30-40 minutes I think(didn't measure it because it wasn't a comparatively long time).

RichD


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## LuxLuthor (Mar 2, 2008)

That delay in the Emoli charging is because your charger is following the safe algorhythm for exploding Lithium Cobalt 3.7V cells which tapers off and changes from applying constant current (CC) to applying pulses of constant voltage (CV), the latter being a slower phase. If I remember right, with LiPo 90% of the voltage is delivered in the first hour, and many RC users stop the charging then, rather than waiting for the last 10% of the charge to be delivered.  Some chargers have a fast charge capability if you know it is safe to use with your cells.


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## Northern Lights (Mar 2, 2008)

LuxLuthor said:


> NL, I have looked at AWR's graph :duh2: that you posted several times, and it is still not clear to me what you trying to show with it....in part because he put all the other test parameter lines for his HotDriver on the same graph, and the lines are hard to figure out. :duh2: oo:
> 
> Correct me if I am not reading this correctly. This is a graph of 3 x 2300mAh A123 in series (from Dewalt pack), running one of the three versions of the 64430 bulbs (Osram, Tungsram, TopBulb) that we have seen. The green current line appears to be exactly 7.5A, assuming that is his HotDriver plot.
> 
> ...


I wish I still had the number the graph came from, but the magnitude of the graph does represent what I am saying, that the A123 read higher than the expected 3.3 on a 5 amp load for the first few minutes.

Gray is battery, Vbattery.
Red dotted is Vbulb taken with a parallel read off the bulb.

Dark gray, driver input is not represented; light gray is the only grey on the graph

Readings are taken during operation of the bulb. 

You mentioned the red dotted line looked to you to be : 
"Vlamp red dotted line shown dipping below the 9.0V line at 2 mins run time" 
I suggest saving the picture to Desktop and enlarging in an editing program to get a better resolution.

 The 64430 bulb is represented in this graph and runs at 7.45 amps
The scale vertical, each horizontal line is 1 volt.
The scale horizontal, each vertical line is 1 minute. 
The GRAY line, Battery Voltage crosses the 9.0 volt at 16-17 minutes.
The RED dotted line, Voltage at the bulb, Vbulb, crosses the 9.0 Volt at 5-6 minutes but does not drop below 9.0 volts until 9-10 minutes, a flat line, flat discharge.

At 1 minute the Gray line is at @9.6-9.8 volts, (pretty close to that at 2 minutes too, it does not cross the 9.0 at 2 minutes)
At 5 minutes in the Grey line is at @ 9.5-9.6 volts
The load is 7.45 amps. Under that load the cells are holding 3.26-3.20 volts each under the 7.45 Amp load.

The load of the 5761 is 5.43 amps, two amps less than the 64430, 2 amps is 26% of 7.45 amps. 

With less of a load the battery voltage would be higher. This is the extrapolation I am referring to and I will do the math to extrapolate it later.

For the first few minutes, under 5 minutes for sure, I measure 6.9 volts at the 5761 bulb and that averages 3.45V for per cell. By my meter and BC-6 charger both of those cells are full charged and read unloaded at 3.6V each or 7.2V for the pack of two.

I think I answered:
If that were true, the gray Vbat line (I only see a single, light gray line which he says is Vbat) would start at 10.8V, then when circuit is completed, the Vlamp red dotted line shown dipping below the 9.0V line at 2 mins run time, would also be higher.
By pointing out that this conclusion is not correct.

The voltage on the graph taken from actual readings, not an equation, starts out over 10.0 volts and drops to @ 9.0 volts at @ 6 minutes, not 2 minutes, and drops below 9.0 volts near 10 minutes, not 2 minutes.

This all occurs under the 7.45 amp load of the 64430 bulb.

My conclusion is with a reduced load of 5.43 amps, reduced by 2 amps there would be even less of a drop in voltage by significant percent to support why I read 6.9 volts Vbulb on a 5761. The nominal voltage of 3.3 volts for the battery is set by the manufacturer as a function of battery performance against an arbitrary load they chose and subject the batteries to. It obviously is not correct for the 5761 project I write about. 

Let’s extrapolate now from the 64430 graph to the 5761.

The unloaded voltage of the 64430 mod batteries is 10.8 volts but when subject to be under 7.45 amps of the 64430 at two minutes the graph shows 9.1 volts.

Now to keep the same load and results for a 5761 we need to take 2/3, two batteries of voltage at the 2 minutes, that is .666 x 9.1 = 6.0606 Vbulb at 7.45 amps.

But the 5761 uses only 5.43 amps not 7.45, 2 amps less or 26% less or it is 74% of the difference between the measured voltage under load and the measured voltage under no load.

Therefore at two minutes the 5761 should be 6.06 volts plus 74% of the difference between 6.0606 volts and 7.2 volts, the difference between loaded with the 5761 and the unloaded battery voltage. 

The math:
6.0606 + {.74[7.2-6.06]} =
6.0606 + {.74[1.14]} =
6.0606 + .8436 =
6.9042 Vbulb

6.9 Volts at the bulb is what I would expect to find at two minutes by extrapolating from this graph as seen above. 6.9 Vbulb is what I measured at the bulb at about two minutes. The hypothesis was proven by actual test.

The graph taken from empirical data from an actual test was true in performance to another bulb, A123 performance of 64430 compared to 5761. The value was reached by extrapolation and was verified on more than one occasion and on more than one light that two A123 batteries at about two minutes will supply 6.9 volts to the 5761 bulb by actual measurements.

What this means is that the A123 actually has a higher voltage under the load of 5 amps and 7 amps bulbs than one expects from the published nominal voltage of 3.3 volts.

Gee, Lux, you put me through some work. BTW I use a Chinese copy of a fluke meter. I have access to good meters, flukes, and that is how I know it keeps its calibration, by comparison. That is how I bought it too. I took some components with me and opened several meters up in the store and took the one with the best tolerances.


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## jimjones3630 (Mar 2, 2008)

NL, 
your math proves what we knew from experience, the empirical data from using A123 2300mah cells. It is a whole lot easier to just say "they don't sag", "they keep 6.9vbulb with 5761 on 2xA123 2300mah cells."

NL, you did at least a days worth of work in your post and by doing that you have shown your work is verifiable and repeatable. These two conditions verifiability and repeatability are hallmarks of scientific work. 

This is what separates opinion from facts.:thumbsup:



Northern Lights said:


> I wish I still had the number the graph came from, but the magnitude of the graph does represent what I am saying, that the A123 read higher than the expected 3.3 on a 5 amp load for the first few minutes.
> 
> Gray is battery, Vbattery.
> Red dotted is Vbulb taken with a parallel read off the bulb.
> ...


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## Northern Lights (Mar 2, 2008)

I wish I could have said just that, so simple just to state:

The A123, they do not sag. 3.3 Volts (6.6 Volts for two) is not the correct nominal voltage with the 5761, 6.9 volts is correct.


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## LuxLuthor (Mar 2, 2008)

NL, something is still not making sense to me. I do have a genuine question about your logic, and that graph is hard to see clearly, so if you can find that file from AWR, can you email it to me?

I appreciate the math you went through, but there is still something that is not looking right. There is the other issue that I had about the resistance in your 5761 setup vs. whatever resistance AWR had in his testbed setup that generated that graph with one of the many 64430 versions.

*Post Edited: * Also NL, thanks for Emails. Discussed with AWR, and he will be sending you and me graphs using the 5761, and explaining about the 26% extrapolation question.


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## morelightnow (Mar 2, 2008)

good, we don't need those arguments here. i wanna see more technical input


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## petrev (Mar 3, 2008)

Hi

Just checked one of my A123s that was charged yesterday (about 18 hours ago) and it is at a rested Voltage of

Ta-Daa

*3.51V*

Any help ?

Cheers
Pete


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## jimjones3630 (Mar 3, 2008)

Hi Pete,

Not sure how to help other than not ridiculing or attacking you for having better performing batteries. Are they 2300mah A123s? if so can you mesure the vbat with your mod and post the particulars, bulb etc here? Fully charged voltage of 3.6v will dissapate over time as they self discharge. 
jim



petrev said:


> Hi
> 
> Just checked one of my A123s that was charged yesterday (about 18 hours ago) and it is at a rested Voltage of
> 
> ...


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## jimjones3630 (Mar 3, 2008)

Lux, if you have a problem with me I suggest you contact me instead of name calling and ridicule. Cheers to you for going to NL via email to help you understand.

jim


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## petrev (Mar 3, 2008)

jimjones3630 said:


> Hi Pete,
> 
> Not sure how to help other than not ridiculing or attacking you for having better performing batteries. Are they 2300mah A123s? if so can you mesure the vbat with your mod and post the particulars, bulb etc here? Fully charged voltage of 3.6v will dissapate over time as they self discharge.
> jim


 
Hi Jim

Just charged 2 x A123 26670 type and they come off the charger at 3.6V as expected and I'm sure would no doubt drop to a rested value as stated before of about 3.5V

Stuck these 2 into a Mag-2D with a JM-SST and measured the Voltage at the Bulb-Pins under-load Hot-off-the-charger 

PH-5761
6.6V @ 5.4A

fairly quickly dropping to a steady

6.3V @ 5.1A then shows usual fairly flat drop from there.

I have noted before that the discharge curve of the A123 (26670 is all I have) is flatter than any other I have seen but due to it's chemistry starts lower than the others - simply (?) match cells to bulbs.

For example the Plasmaman GE-34711(8) works well with 3xA123, Flashes with 3xe-Moli(Hot) and works great with 3xe-Moli +AW-SS.

I find the AW-SS takes a bit off the top from a system as well as SoftStarting as it seems to run at 98% duty-cycle flat out - this really suits some bulbs well but some others are better DD-A123 or with a JM-SST in my experience ! !! !!!!!!! for what that's worth !

Posted other experiences with these cells and AW-Clions Here and Here

Cheers 
Pete


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## jimjones3630 (Mar 3, 2008)

Hi Pete,

I should know the answer to this after following JimmyM development of teh SST. But I don't off hand so using the JM-SST at 100% duty cycle does it take off the top some of the voltage? If not then it is only soft start which is what it does IIRC. AW's c drive would and on the order of about as much as a NTC. 

Curious about "26670" nomenclature. is that the same cell as this link?
http://a123systems.textdriven.com/product/pdf/1/ANR26650M1_Datasheet_NOV_2007.pdf
jim



petrev said:


> Hi Jim
> 
> Just charged 2 x A123 26670 type and they come off the charger at 3.6V as expected and I'm sure would no doubt drop to a rested value as stated before of about 3.5V
> 
> ...


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## SilverFox (Mar 4, 2008)

Hello Northern Lights,

Why is there such a big difference in the system resistance between the two lights?

You observed that the 3 cell light started out at 10.8 volts, then dropped to around 9.7 volts under a 7.45 amp load.

Using ohms law I come up with a system resistance of around 0.148 ohms. The data sheet for the cells state that you can expect around 0.010 ohms per cell, so for 3 cells I could subtract out 0.030 ohms and end up with 0.118 ohms for the rest of the circuit.

Moving on to the 2 cell light. You observed a starting voltage of 7.2 volts which dropped to 6.9 volts under a 5.43 amp load.

Once again plugging the numbers into ohms law I come up with a total system resistance of 0.055 ohms. If we remove the internal resistance of the 2 cells, we end up with 0.035 ohms.	

This indicates that one light has over 3 times the resistance as the other one. Is there really that much difference in the lamps?

Tom


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## petrev (Mar 4, 2008)

jimjones3630 said:


> Hi Pete,
> 
> I should know the answer to this after following JimmyM development of teh SST. But I don't off hand so using the JM-SST at 100% duty cycle does it take off the top some of the voltage? If not then it is only soft start which is what it does IIRC. AW's c drive would and on the order of about as much as a NTC.
> 
> ...


 
Hi Jim

Yes JM-SST is a PWM softstarter and if you set the trim pot to the 100% region then there is nothing off the top. Trim pot goes from fast softstart through slower softstart to reducing duty cycle so that there can be some max duty cycle adjustment for sensitive lamps or oversize packs.

My nomenclature is just wrong as I always use the measurement from my cells so that I can work out actual lengths for Mags etc. My 26650 A123s still have some of the tabs on them after cutting away excess so thay are nearer 26670 to the nearest whole number. I leave some of the tab on so that they actually touch without need for magnets or anything. Hope it didn't cause any confusion - I haven't got different cells from everyone else.

Cheers
Pete

ps. Hi Silverfox

Sag (effective internal resistance ?) varies with current draw so for a higher current draw the loss of voltage will be greater - hence the discharge curves at different draw rates like these 









Does that make sense ?

Original Data Sheets

A123 ANR26650M1

e-Moli IMR26700A

e-Moli IMR18650E

Again Pete


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## JimmyM (Mar 4, 2008)

This is a great thread. I've been looking quite closely at the A123s as of late, due to their flat discharge curves. In developing a PWM regulator, a friend came up with a "cheat" to get the chip to regulate the RMS voltage over a narrow range without using an RMS converter. The A123s work really well for this. 3 A123s driving a 5761 at 7.2V varies only 0.01-0.02V over the discharge of the cells from 10.8V to 9V. And it has a softstart feature as well.


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## jimjones3630 (Mar 4, 2008)

Pete, thanks for the great graphs and explaination. Seen several threads related to A123 cells with a lack of distinction between A123 2300mah cells and A123 18650 size and performance.

When recharged to 3.6v the manufacture's recommendation 2 cells powering a 5761 I have measured up to 7v at the pins. From there have relied on change in color temp for recharging que. SiverFox has a neat calulation for determining the battery state by length of run time. 

It is these two point which I'm interested. Proper charging level and not overdischarging these tough cells which can take down to 2.0 ov and be recovered. I and others have done so with 2300mah cells and look with jaundice eye at the claims made of other A123 cells types. 

Getting to know A123 2300mah cells takes some time. Wild claims they can be treated like a lady of the night are irresponsable and not helpful. While they sag less than Emoli cells and all cells do sag to some extent I tell folks these cells don't sag for the purpose of not over discharging them. Very easy to watch a torch shine bright for 30min then dim a bit and remain somewhat bright and drain the cells below 2.0v into unrecoverable territory.

jim



petrev said:


> Hi Jim
> 
> Yes JM-SST is a PWM softstarter and if you set the trim pot to the 100% region then there is nothing off the top. Trim pot goes from fast softstart through slower softstart to reducing duty cycle so that there can be some max duty cycle adjustment for sensitive lamps or oversize packs.
> 
> ...


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