Assembly, testing, and calibrating of the PhD-M6 packs - picture heavy!

wquiles

Flashaholic
Joined
Jan 10, 2005
Messages
8,459
Location
Texas, USA, Earth
The PhD-M6 battery pack is a custom pack for the Sure Fire M6, and it is composed of a custom battery pack designed and built by Eric (mdocod), and a custom PWB/driver and firmware done by me. Eric recently finished a great post showing how he creates the PhD-M6 custom battery pack, and this post shows what happens after Eric sends me the finished battery carrier to become the complete PhD-M6 pack.

Here is the panel with the bare PhD-M6 production boards that I designed (again, kudos to Alan, Jimmy, and George for their help!):
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These are the parts I got from Digikey for this board:
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I am using a Metcal MX-500 with the stylus wand:
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For solder I am using this outstanding Kester solder and flux pen:
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I will be updating the order as I build more and more of these, but first I start with the 5V Voltage regulator:
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then the MOSFET:
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then the Tiny85:
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then the DIP switch:
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I then do the resistors - yes, they are that small (0805 to be exact):
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more resistors:
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Then I move into the capacitors:
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Trivia - which capacitor has a higher value? :devil:
(the small cap is a 1uF - the large one is a 100uF!):
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But we don't need anything that big. These are the sizes I will be using:
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As you can see in the pictures, the board has been progressively getting more and more dirty with the flux. Since this water-soluble flux is somewhat corrosive, it MUST be cleaned. First I separate the finished boards from the panel:
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Then to clean the boards in an ultrasonic water cleaner for 5 minutes:
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Once they are ready, they need to be dried off:
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Nice and clean:
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I first remove the cover that protects the switches from the "bath":
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Now they are ready to be tested:
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I first check them in my special fixture. Here I am using low current protected cells in case I have a short/problem. Assuming things are well, this fixture allows me to test the 5V regulator and verify that the AVR Dragon tool can read/talk to the Tiny85:
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Once I can read the signature, I do the initial programming, set the fuses and lockout options, and then I am ready for the next step:
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Here are the two prototype packs that are going out for field testing. One for Eric, and one for forum member leukos:
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I disassemble the top of Eric's battery carrier:
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place the board and center:
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install the outer screws/stand-offs:
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then the center (Battery plus) and lower center (Battery minus) connections:
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I then install the protected 17670 cells - NOTE that Eric clearly marks the Pos and Neg side for each of the 3 cells. The pack might be damaged if the cells are connected backwards!:
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I first check the pack's voltage (note I am using my Son's Scooy-Doo band-aid for a boo-boo in my finger!) :
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then I check the regulated DC voltage at the Tiny85:
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Once the pack is running good, I then proceed to test what are the outputs, so that I can calibrate each pack with a small correction factor. This part is slow, but makes sure each regulator is as close as possible to the target voltages as possible.

Please note two things:
1) You can't measure the regulated output into a bulb with a normal True-RMS voltage meter. You need a special meter that can measure both the AC and DC components of the PWM signal, as True RMS meters only measure accurately at a duty cycle of 50%. Since the regulator varies the duty cycle to compensate for the battery as it drains, only a meter with AC+DC capability will give you the correct value.

2) The pack goes to sleep if there is no bulb across the pack. If you put a bulb across the pack, then the regulator will wake up and start regulating, which would then allow you to use your AC+DC meter to measure the actual RMS Voltage.


First test the 4.9 volt output - note that the output does vary a bit between photos as the regulator is constantly adjusting/compensating as the battery drains:
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Then the 6.8 volt output:
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Then the 7.4 volt output:
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and the 10.8 volt output:
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Then compare to the target:
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Calculate an average compensation factor, and re-program the pack:
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After calibration, these are the new outputs (4.9 volt target):
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6.8 volt target:
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7.4 volt target:
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and 10.8 volt target:
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Here is the completed and calibrated PhD-M6 pack:
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I then set the DIP switch to HIGH-LOW, to select level 3, 7.4 volts, since I am testing with the N2 in my own M6:
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Insert pack into M6:
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and voila! - a 12 volt battery pack safely driving an N2 at a regulated 7.4 volts RMS:
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I then finished the second pack:
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That is it for now - thanks for watching :)
 

Yavox

Enlightened
Joined
Mar 7, 2009
Messages
206
Location
Poland
This is one of the most interesting posts I have read for a long time and now I understand the price of your PhD-M6 pack. Moving to Marketplace and starting to look for my first SF M6 now...

Thank you! :thumbsup:
 

RichS

Flashlight Enthusiast
Joined
Oct 22, 2007
Messages
1,509
Location
USA
Amazing job on bringing the PhD-M6 to fruition, and great detailed post of the assembly! I'm on the list to get one of these, so...when do you anticipate I'll get my hands on one? :huh::huh::popcorn:
 

wquiles

Flashaholic
Joined
Jan 10, 2005
Messages
8,459
Location
Texas, USA, Earth
Thank you guys :eek:


...when do you anticipate I'll get my hands on one? :huh::huh::popcorn:
Soon. Very soon :D

The first two packs leave tomorrow morning for my two system testers for a good field trial. Once I get enough feedback from them on what (if any) needs to change in the firmware, and assuming no show stoppers, I will start a formal sales thread.
 

leukos

Flashlight Enthusiast
Joined
Apr 8, 2004
Messages
3,467
Location
Indianapolis
:thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::thumbsup:
Excellent work up, Will! This is one of the most exciting things to become available for us Surefire incan lovers since I have been a part of these forums. I'm glad you and Eric have both given us threads that can help us understand all the work and attention to detail that has gone into creating these packs. It really has been a labor of love and I hope it is very successful for you. Anyone who doesn't order one will really be missing out on something special here. Good luck, and I'm looking forward to receiving one!
 
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