# 4 "F" cells in a 6D Mag w/Volt and Amp readings.



## BigusLightus (Jan 6, 2009)

Just assembled the first of my "Naukatoothunderphuk" lights.







This is a 6D Mag, AW three speed soft start switch and socket, Osram 64625 lamp, Boro lens, and 4 "F" size LiFePO4 batts. The batts required the top of the paper wrapper to be trimmed to allow them to make contact with each other. As soon as my Kapton tape arrives I wrap the top of each batt.

I'm just charging the batts for the first time. Thus the beamshots will have to wait a bit.


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## Helmut.G (Jan 6, 2009)

*Re: Just assembled the first of my lights*

nice light, fits your username as well:thumbsup:


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## donn_ (Jan 6, 2009)

*Re: Just assembled the first of my lights*

What setup are you using to charge the cells?

From what I've read, you'll be seriously under-driving the lamp. You'll probably come in well under it's 12V default rating.


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## BigusLightus (Jan 6, 2009)

*Re: Just assembled the first of my lights*

Underdriven? I was concerned about flashing on start up with fresh cells. Here is the description from the cells: *Li-Fe-PO4 Rechargeable: 32900P ( F size) Cell 3.2V 4.5Ah, 90A Rate.*

I'm guessing there will be very little sag with these. 3.2V nominal x 4 equals 12.8V. The safe zone is what I was hoping for. As soon as these charge up I'll measure and test everything. I might even try to check the Voltage at the pins of the bulb.

For charging I'll be using a Hyperion 1210 in A123 mode.

The four F cells fit perfect in the 6D tube. I'm excited.


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## donn_ (Jan 6, 2009)

*Re: Just assembled the first of my lights*

You'll lose somewhere between 2 and 3V to switch and spring resistance.


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## BigusLightus (Jan 6, 2009)

*Re: 4 "F" cells in a 6D Mag*

Even with the AW switch?


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## donn_ (Jan 6, 2009)

*Re: 4 "F" cells in a 6D Mag*

From what I understand, the switch is most of it. 3-4 times normal spring resistance, IIRC.


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## lctorana (Jan 6, 2009)

*Re: 4 "F" cells in a 6D Mag*

Easily checked.

With the large bi-pin bulbs, it is possible to attach test leads to the pins and test the actual bulb voltage under load.

I think you've done a great mod. The soft starter should take care of the overvoltage nicely.


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## BSBG (Jan 6, 2009)

*Re: 4 "F" cells in a 6D Mag*



BigusLightus said:


> Even with the AW switch?



The AW D Switch is about 200 mOhm - similar to a stock Mag switch.


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## BigusLightus (Jan 6, 2009)

*Re: 4 "F" cells in a 6D Mag*

Just measured each batt separately and together, just to make sure. Total open Voltage is 13.29. Voltage at the pins of the bulb is 11.94 on high, 7.24 on medium, and 4.08 on low. 13.29 - 11.94 = 1.35. So, I'm only loosing 1.35 Volts to losses. This is on brand new batteries that have not been charged by me yet. I'll post the post charge Voltages tomorrow. 

During the test this thing was sooooo bright that it scared me. I could feel the heat during the few seconds of on time.

Tail cap current test are: 3.83A on low, 6.04A on medium, and 8.84A on high. Please note, I was holding the test leads by hand and might not have had the best of connections. I test for current twice and got the same readings except for high was down 3 100ths of an Amp.


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## VegasF6 (Jan 6, 2009)

Neat! Make sure you wear your safety glasses when working in the head of this thing, and be carefull with those probes! Man, those cells are no joke.


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## BigusLightus (Jan 6, 2009)

It never occurred to me to take safety precautions. Really. This is only a flashlight, right?

I will take your advise VegasF6. After all, I use protective safety equipment for most of my other hobby projects. I wonder why it never occured to me?

Thank you for the enlightenment.


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## Bimmerboy (Jan 6, 2009)

BigusLightus said:


> It never occurred to me to take safety precautions. Really. This is only a flashlight, right?
> 
> I will take your advise VegasF6. After all, I use protective safety equipment for most of my other hobby projects. I wonder why it never occured to me?
> 
> Thank you for the enlightenment.



VF6 is a good guy.

Sarcasm is an excellent tool when used _properly_.


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## lctorana (Jan 7, 2009)

*Re: 4 "F" cells in a 6D Mag*



BigusLightus said:


> Voltage at the pins of the bulb is 11.94 on high...


 
So it's *only just* underdriven. By 0.06V.

Doing resistance fixes (e.g. tailcap spring braid, DeOxit & ProGold etc) will give you a few extra lumens yet.

At the moment, giving the bulb exactly its design centre voltage makes it what I call a "rightwire" rather than a "hotwire". It's a kind of torch I'm just getting into now - using super-hot bulbs at design voltage.

That way, you get mega lumens, with full bulb life.


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## 2xTrinity (Jan 7, 2009)

*Re: 4 "F" cells in a 6D Mag*



BSBG said:


> The AW D Switch is about 200 mOhm - similar to a stock Mag switch.



Can't be that high...



BigusLightus said:


> ...Total open Voltage is 13.29. Voltage at the pins of the bulb is 11.94 on high, 7.24 on medium, and 4.08 on low. 13.29 - 11.94 = 1.35. So, I'm only loosing *1.35 Volts to losses*. ...
> Tail cap current test are: 3.83A on low, 6.04A on medium, and *8.84A* on high. Please note, I was holding the test leads by hand and might not have had the best of connections. I test for current twice and got the same readings except for high was down 3 100ths of an Amp.


FYI a simple multimeter will NOT be able to accurately measure RMS voltage at medium and low, as the AW switch is PWM modulated, not a DC or simple sinusoidal AC voltage.

Anyway, back to the results from the "High" settings:

R = V / I
R = 1.35 / 8.84 = 152 mOhm

That's the resistance of EVERYTHING in the system -- including the cells, the spring, the switch, the bulb contacts, and a multimeter and leads.

Keep in mind this is for the maximum setting, where the mosfet switch is on with 100% duty cycle. Good MOSFETs are on the order of ~10mOhm when on. The switch will be lossier at lower settings, where the switch is being pulse-width modulated, but this can't really be quantified with a simple resistance value.


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## BigusLightus (Jan 7, 2009)

I'm sincere in thanking Vegas for his advice. I honestly don't know why I didn't think of it before. I hope I didn't offend or mislead anyone.

The multimeter I used was a Fluke 87 III. A true RMS meter which is quite expensive. I've not calibrated it for use with PWM but I'm confident it is close. Is there a known PWM source that I can test it on?

Thank you


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## Bimmerboy (Jan 7, 2009)

Eeek!... my mistake, BL. Darned internet communication. 

BTW, cool mod, and I must repeat VF6... those cells are truly no joke! Wow... 90A. On paper, it looks like four of those could power an 1100W mod!


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## BigusLightus (Jan 7, 2009)

Four more of these cells would probably start my car.


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## donn_ (Jan 7, 2009)

I'll be curious to follow your impressions of the F cells as you use them. I'm a convert to A123s, but so far, in the smaller sizes, 18650 and 26650. I intend to try some M cells soon.

I'm also interested in charging procedure and times. Are you doing them individually, or in series? If in series, are they staying balanced?


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## BigusLightus (Jan 7, 2009)

Hi Donn,

I'm charging as we speak. Using Hyperion 1210 in a123 mode. Charging at 1C (4.5A). Doing each one separately so its taking longer but I feel safer that way.

One of my Christmas presents was a CBA II. I'll be cranking that up soon and will go nuts with all my batteries. I'll post the outcomes here when finished.

I also have some A123's and Emoli's. But those are for other light projects that I've not started yet. I just picked up a brake hone to slightly bore a few C Mags.

Thanks for asking.

Update: Voltages fresh off the charger. Only one minute or less of resting time.
batt #1 3.460
batt #2 3.495
batt #3 3.631
batt #4 3.464


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## BSBG (Jan 7, 2009)

*Re: 4 "F" cells in a 6D Mag*



2xTrinity said:


> Can't be that high...



Hey, I am just repeating what AW said in his sales thread: https://www.candlepowerforums.com/posts/2334383&postcount=122


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## Bimmerboy (Jan 7, 2009)

BigusLightus said:


> Four more of these cells would probably start my car.



Funny you mention it. Have you seen this?


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## 2xTrinity (Jan 7, 2009)

*Re: 4 "F" cells in a 6D Mag*



BSBG said:


> Hey, I am just repeating what AW said in his sales thread: https://www.candlepowerforums.com/posts/2334383&postcount=122


I read the post. AW said he ended up with 200mOhm in an assembled light. He might have been talking about the total resistance of the light (switch, cells, spring etc), including the switch.

He likely did a similar test to BigusLightus, whose entire light had a resistance of ~150mOhm based on the current and voltage figures he gave.


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## BigusLightus (Jan 7, 2009)

Remember the Oldsmobile ad?

This isn't your Father's battery!

Last night I was thinking "How much power does it take to start my car?". All I can document is the 1400 watt rating on my starter. So thats my starting point. 1400 Watts / 12 Volts equals just under 167 Amps of current. So, I'm guessing that 2 parallel strings of 4 in series would start my car. All I need to do is keep two of these monster lights in my car for emergency starting and a special holder that can handle the current and my car is good to go.


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## mdocod (Jan 8, 2009)

Actually, the 4 you have there would probably start your car on a warm day without too much trouble. The trick is getting a good enough connection between the cells, and from the cells to the battery cables of the car. It would likely burst over the 90 amp maximum discharge rate for a moment, but a pulse of 2 seconds over 90 amps wouldn't be that big a deal.


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## VegasF6 (Jan 8, 2009)

Well there is an idea then. And it may be a CPF first. An integrated charge jack that doubles as a set of jumper cables!


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## Juggernaut (Jan 8, 2009)

mdocod said:


> Actually, the 4 you have there would probably start your car on a warm day without too much trouble.


 
If your math is correct , you are correct, 4 should be plenty to start most cars, _funny recent story_: last weekend I was going to pick up my friend so after de icing my car, I went to go start it “battery has many miles on it and needed to be replaced “I did the next day”” anyways the car was dead and both my parent’s cars were at work:sigh: so I decided to test my theory:thumbsup: that either my Bigbeam 1000 Ultra Mod or My Big beam 1766 C Power House could start a car:devil: “I had no other choice except, to wait hours for my trickle to recharge the car battery.” so I grabbed my 1766 C’s battery chucked it on the jumper cables and turned the key…The car’s starter gave a couple of revolutions real slowly so I stopped:shrug:, waited a minuet and turned the key again, vroom the engine roared to life. So it is possible for a heavy duty flashlight to start a car:twothumbs.


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## 2xTrinity (Jan 8, 2009)

mdocod said:


> Actually, the 4 you have there would probably start your car on a warm day without too much trouble. The trick is getting a good enough connection between the cells, and from the cells to the battery cables of the car. It would likely burst over the 90 amp maximum discharge rate for a moment, but a pulse of 2 seconds over 90 amps wouldn't be that big a deal.


Scenario:

I can just picture jump-starting a guy in the middle of the night:

Them: "Oh, I already have a flashlight (pointing to half-dead mag solitaire on keys), why don't you get your engine started"
Me: "No need -- I don't need this flashlight isn't to see with, I'm going to use the battery to start the car..."

:laughing:


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## BSBG (Jan 10, 2009)

*Re: 4 "F" cells in a 6D Mag*



2xTrinity said:


> I read the post. AW said he ended up with 200mOhm in an assembled light. He might have been talking about the total resistance of the light (switch, cells, spring etc), including the switch.
> 
> He likely did a similar test to BigusLightus, whose entire light had a resistance of ~150mOhm based on the current and voltage figures he gave.



I'm not sure about that, based on this: https://www.candlepowerforums.com/posts/2472150&postcount=5 

After reading it 2-3 times, I am still not sure if the spring is included or not:thinking:


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