How far can I push it?

[donn_]

I can get 5x 26650 A123 cells into my 6D 64623 light. Those cells will measure between 16.5V and 17V.

In Lux's Destructo Charts, this bulb flashed at 16.9V.

There are no resistance fixes in this light, and it's running one of AW's soft-starters. There's also a 1.5" copper spacer to fill up the tube.

Will it flash, or will it work?

:devil:

 

[modamag]

donn, you'll be OK with 5x.

Fresh off the charger these should be 3.65V / cell.
But once you put any load (1C) on the A123 they drop to < 3.3V/cell.
You're gonna be pull mucho 4C on that baby during the run and alot more when it's cold start.

sOT: One thing to keep in mind is to terminate charge @ 3.65V I had a few that failed inside the Dewalt pack due to inballance and were charged to > 4V of their charger. These were revived but loss somewhere btw 10-20% capacity & suffer the worst during heavy draw.

My application is 30-40A of a 4P pack.

 

[donn_]

Thanks, mate.

Maybe I should just move up to the 64633. They don't cost much more, and I'll get more lumens and bulb life.

That looks like as far as I can go, and still use the AW soft-starter.

You're gonna be pull mucho 4C

That C stuff is way over my head. I'm using these cells because of the quick recharge, and their supposed ability to handle heavy draw.

 

[mudman cj]

I don't think you would go wrong with either one, but they do have some interesting advantages and disadvantages as I see it.

Advantages of 64623:
-Whiter color temp
-Higher efficiency in the visible spectrum
-9.4% longer runtime from Luxluthor's measured currents
-Shorter filament for better focusing


Advantages of 64633:
-7.2% more predicted lumens output from Luxluthor's lux measurements (assumes 16.25V pack voltage)
-In excess of 7.2% more infrared output for starting fires :devil: because of the combined effects of increasing power output and shifting the spectrum further into the infrared (lower color temperature).
-Longer bulb life

IMO, this is probably a show off light primarily due to the short runtime, and therefore more lumens means a bigger smile. And who wants to say, "No, really. It does start fires. Yeah, sure. Let me get some newspaper..." only to have to wait through agonizing seconds of torture wondering exactly when it's going to burst into flames. :sweat: But I wonder how much quicker the 64633 would start a fire or from how much further away it could be done. The differences may not amount to much or matter to some.

 

[LuxLuthor]

You have at least 300 mOhms of resistance (220 from AW's D Driver alone), so if you are running a bulb like 64623 which uses a ballpark of 10Amps, that will drop 3 volts (10A x 0.3 Ohms). You still have a startup current spike with a cold bulb filament which is what instaflashes most bulbs, but you should be far enough from the edge to not have a problem.

Problem with trying to go up to the 64633 150W Osram is that it needs more voltage than 16.5V (5 x 3.3V A123's) will deliver (especially subtracting the resistance voltage drop), and it will just look crappy being underdriven.

 

[donn_]

...it will just look crappy being underdriven.

Well...maybe not overdriven as hard, as opposed to underdriven.

I'm currently running the 623 on 4x A123s, and while it isn't pushing the lamp as far as it can be pushed, it looks pretty good.

At 16.5V, the 633 provides 7067L for 15.9 hours. The 623 provides 6589L for 16 hours. There's probably a little less chance of flashing the 633, no?

Another question...the cold filament issue. Does the AW soft-starter adequately warm the filament, or does it flash at even the lowest level?

As for fire-starting, I have one of these:

:devil:

 

[mudman cj]

That is a nice firestarter donn_! :laughing:

Luxluthor makes a good point. My estimates of difference in light output and runtime difference are off because I didn't account for voltage drop in the rest of the circuit (everything except the bulb filament). So the 64633 will only be driven at 13.25V give or take and will be quite yellow. With 300mOhm resistance dropping 3V in the light, you would get a nicer result with a 6th cell for around 19.5V, but I know that's probably not a good option. So, I have to agree with Lux that the 64623 is going to look better, especially since you seem more interested in the light than the heat.

 

[modamag]

Regarding soft starting, only 100ms is require to ramp up the filament. I think AW's driver is running like 1000ms or so. All SS does is slowly let the current in.

The low/med/high is just the duty cycle (how fast you turn it on-off-on). It should not make a significant difference between these modes.

IMHO, the voltage sag under load is the more important factor. With SS you're not shocking the filament but with enough voltage you'll still pop the bulb.

If you're brave enough try out the molicell from Milwaukee V28 pack. With 5x of those cells & the 623 you'll get one heck of a light.

Here's the theory.
5x Molicell 26600 are 3Ah so you'll be pulling like 3.4C effectively 3.8V/cell max.

So 3.8V * 5 cells - 3V switch resistance will give you 16V.
[size=+2]This should put out twice as much lumens compared to the M1 cell setup[/size]

 

[donn_]

I just measured a string of 5 of the Emoli cells, and got slightly over 20V. They haven't been charged recently, but measured 3.97 to 4.1 each.

They haven't been shrinkwrapped yet, but I've been using them in D-Mags with a 1" poly irrigation tube sleeve.

The problem is they take so much longer to charge than the A123s. I really need to upgrade my charging hardware.

 

[modamag]

Hot off the charger they're 4.2V.
Sitting for a while they'll drop 0.1-0.2V

However the magic occur while under load i'll just be 3.5-3.6V.

 

[donn_]

<GRIN>

I was reading your thread on the Colossus Vaporizer, when the email alert to your reply popped in.

Sounds like a real beast of a light!

 

[LuxLuthor]

Well...maybe not overdriven as hard, as opposed to underdriven.

I'm currently running the 623 on 4x A123s, and while it isn't pushing the lamp as far as it can be pushed, it looks pretty good.

At 16.5V, the 633 provides 7067L for 15.9 hours. The 623 provides 6589L for 16 hours. There's probably a little less chance of flashing the 633, no?
:devil:

When I said the 64633 being underdriven, I was taking the ballpark resistance of your setup, and the voltage of cells under load into account.

Your Lumen & Bulb Life estimates are taken from my destructive testing chart, but if you are measuring 16-17V without load, then under load resistances of AT LEAST 300 mOhms x 11.5 Amps, you must subtract 3.3Volts, putting you below the default manufacturer's rating, and underdriving it.

In contrast, anything over 12V is overdriving the 64623 bulb from default ratings...but it is almost certain that 4 x A123 cells is also underdriving that bulb. Those cells drop to 3.3V almost immediately under load, so you are starting with only 13.2V, then again must subtract 3 Volts from resistance losses.

AW's driver indeed has the effective soft starting effect of blocking the sudden inrush current into a cold filament.

My graphs of the LiMn vs. A123 show the voltage range differences under loads. These are 18650 size cells, but the 26700 size of A123 vs. Emoli in terms of voltage under load will parallel these charts. The higher voltage of LiMn is one of the reasons (in addition to more common charger algorhythm, and availability, etc) some of us prefer these cells. Obviously the RC crowd wants maximum amp output, so for them the A123 is preferred.

 

[donn_]

I think I'm making progress, both in understanding the science and testing it out.

I put the 5th cell behind the 623, and the result is outstanding.

Now I'm thinking about a 6th cell. I have sufficient extensions to go to 7 or 8 cells. Tell me if my reasoning is accurate:

6xA123 is 19.8V before resistance loss. Figuring at least 3V lost to switch and other resistance, plus additional loss due to the added joint in the tube, still keeps me below the 16.9V flash point of the lamp.

Right?

Using the 633 instead, with 6xA123 gets me about a thousand more lumens, a few more degrees of heat and about 30% shorter bulb life.

Right?

Of course, I may need a sling to carry what will essentially be a 7D Mag with a 3" head.

 

[modamag]

IMHO, worth a $4 try
If I was a betting man, I'll give you 30% of sucess from fresh cell.

If you have the equipment, drain 20% from your cell first before trying.

Geesh, Mag7D with 3" head and 6x A123, that thing must be like 8 lbs. You'll get your excercise for the day by wielding it :nana:

 

[donn_]

The problem is I only have 1 lamp right now. I'm placing an order today for more, both 623s and 633s, and possible some others. Once they arrive, my bravery will increase.

When will you have some black Colossus heads?

 

[mudman cj]

I think I'm making progress, both in understanding the science and testing it out.

I put the 5th cell behind the 623, and the result is outstanding.

Now I'm thinking about a 6th cell. I have sufficient extensions to go to 7 or 8 cells. Tell me if my reasoning is accurate:

6xA123 is 19.8V before resistance loss. Figuring at least 3V lost to switch and other resistance, plus additional loss due to the added joint in the tube, still keeps me below the 16.9V flash point of the lamp.

Right?

Using the 633 instead, with 6xA123 gets me about a thousand more lumens, a few more degrees of heat and about 30% shorter bulb life.

Right?

Of course, I may need a sling to carry what will essentially be a 7D Mag with a 3" head.

I think it has a better chance of working than not. As Lux said, you will lose over 3 volts from the 19.8V pack voltage under load. There would be no way without the soft start, but with it you should have the same situation as Lux did when he slowly ramped up the bench top power supply.

 

[LuxLuthor]

Donn, the only concern I have is the starting voltage of fully charged A123 cells starts at 3.5V before it quickly drops to a more stable 3.3V, so I'm not sure when you push up to the flash limit of my destructive tests if the AW soft starting delay will cover that brief initial higher cell voltage. When you push to the edge, anticipate a bulb failure and/or reduced life.

I never completed the bulb life part of my destructive tests, so those life estimates are not reliable.

I'm not exactly sure how much your total resistance is. I'm starting with AW saying his driver was 220mOhms. I have verified that tailcap spring resistance is 60mOhms, and every contact point will have some increase in total resistance.

 

[TKO]

Problem with trying to go up to the 64633 150W Osram is that it needs more voltage than 16.5V (5 x 3.3V A123's) will deliver (especially subtracting the resistance voltage drop), and it will just look crappy being underdriven.

Lux,

I have to beg to differ. My Sleeper mod is quite white on high, but then I do have a low resistance tail cap mod.

Best Regards,

Rick

 

[LuxLuthor]

Lux,

I have to beg to differ. My Sleeper mod is quite white on high, but then I do have a low resistance tail cap mod.

Best Regards,

Rick

Rick, it may be brighter than many lights you have seen, but 5 x 3.3V = 16.5V @ 11.3Amps. With 220mOhms in AW D driver, and at least 30mOhms for other resistance, you are losing almost 3 volts (.25 Ohms x 11.3A = 2.83V).

The default spec of the bulb is 15V @ 10A giving 5600 bulb lumens. However nice it looks to you, it is being underdriven at less than 14 Volts. Put 5 Emoli 26700's in it, or a 6th A123, and you'll see what it should look like. With various 2000+ lumen output bulbs, quite honestly they all look white and bright to our eyes, so I'm not questioning what you see.

If you like it the way it is now then by all means, enjoy it. My point is to underscore that this issue of resistance losses is real, and has an effect on the bulb output and color. Most of these bulbs are not meant to be underdriven vis-a-vis light color and lumen output.

 

[donn_]

..5 x 3.3V = 16.5V @ 11.3Amps. With 220mOhms in AW D driver, and at least 30mOhms for other resistance, you are losing almost 3 volts (.25 Ohms x 11.3A = 2.83V).

I'm really confused about this calculation of voltage lost to resistance.

Your formula is applying the resistance (.25Ohms) to the Amp draw with the un-resisted voltage (16.5V).

Where is the amperage? At the bulb? If so, wouldn't you use the Amp draw of the resistance reduced voltage?

I'm putting together a 3D Mag with an AWR HD set at 11.1V and running 3x Emoli cells. Which bulb is better, 1164 or 1185?

Sorry to be such an idiot about this, but I'm trying to learn how to figure it out myself. I have enough of these two flavors of bulb to afford to blow a couple, but I'd like to be able to make an educated guess.