# Thread: Feedback/impressions on the PhD-M6 custom battery pack

1. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Hi Justin Case,

Post #56 is sort of the pre-face for how I built the chart and came up with this concept of "heat factor." When I actually sat down and started punching out numbers (pages and pages of calculations), I made adjustments to account for more variation in cell condition and age, basically, I moved conservative.

Finding the heat generated within a cell at a 2C discharge rate is pretty much just a function of calculating for power distribution within a series circuit based on resistance in each part of the circuit. The cells represent a certain portion of the resistance of the entire circuit, so as long as the resistance of the cells is a known value (I tested and studied and came up with a value), and the rest of the circuit is a known value (pretty easy to calculate with a few known operating conditions) we can calculate the amount of electrical energy will be lost to heat within any portion of a circuit.

For calculating "heat factor" the exact resistance of the cells isn't super critical, as long as you use the same constant for all calculations things will come out about the same.

For each bulb, a snap-shot of a theoretical point during a discharge under PWM regulation is created. The snap-shot calculates the amount of energy that goes to the bulb, and the amount that is lost to resistance in the cells.

When the amount of energy converted to heat in the cells rises above the amount calculated for a normal direct drive 2C discharge, the "heat factor" rating goes above 1.

The maximum continuous run recomendation is the estimated total run-time divided by the square of the heat factor.

Eric

2. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

So the denominator of the heat factor is not a constant since the series resistance divider will vary depending on bulb.

That seems somewhat unusual since it would appear that instead of using an absolute reference value, you are using a variable reference. So a 1.0 heat factor for one bulb may not necessarily mean the same actual heat generation (say in watts) vs a 1.2 heat factor for some other bulb.

Also, I'm not sure I understand your rule of thumb that the amount of time to let the light cool down is given by multiplying the heat factor by the max continuous run time.

I would think that the cooling rate of the light would be essentially constant, independent of bulb (assuming other variables are held constant, such as ambient temp, air velocity, hand position on the light). So why would something like a 5761 have a shorter "cool down" time vs something like an 1160? Once the light heats up to whatever critical temperature is deemed to warrant shutting down, it would seem to me that the time to cool back down to some acceptable temperature is independent of the bulb. It's a constant heat capacity, and thus a constant amount of energy absorbed to reach the given recommended shutdown point.

3. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Troop#26
Hi Eric,

I noticed that my values are a few tenths more than yours in most cases, 6.8V for MN21 (yours being 6.7V) and 9.2V for MN61 (your being 9.1V). Is that just more safety on the bulb life or do you think that my extra tents will be pushing the lamp to far?

Thanks again for all your help!

Stephen
Hi Stephen,

As I understand, your application could be defined as "very rugged." On CPF, I'm sure there is a wide array of applications for the M6, ranging from shelf queens to the absolute most abusive environments imaginable.

The default voltage values were selected with certain traits in mind that would allow for bulb options that could meet a fairly wide array of possible requirements.

Running the SF HOLA options at 6.8V represents the side of CPF that wants to see something that dazzles the senses a bit, while not breaking out of the scope of some reliability. Running the SF LOLA options at 7.5V moves to in the direction of conservatism for bulb reliability. The 7.5V setting winds up doubling as a way to move back in the direction of dazzling as you move up the LF M3T bulb list. It's a neat balance of options for most people.

The reality is that, you may never have a problem with a configuration that drives all bulbs pretty hard, but when bulb failures can translate to serious danger very quickly in your line of work, I would be the type who would sacrifice some output for some reliability. Lower drive levels will generally produce better bulb life. Lower drive levels should also theoretically reduce the risk of bulb failure from physical shock. (No guarantees of course!)

Tuning a specific arrangement of recommended voltages for a specific application isn't easy and will always involve trade-offs that result in imperfection. Considering your most recently posted list of bulbs with highlighted options, I would lean towards 6.6-6.7V, 7.3-7.4V, 9.0-9.1V, and 10.8V. This would be a reasonably conservative approach that I would feel more comfortable with in harsh conditions.

Eric

4. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by mdocod
The reality is that, you may never have a problem with a configuration that drives all bulbs pretty hard, but when bulb failures can translate to serious danger very quickly in your line of work, I would be the type who would sacrifice some output for some reliability. Lower drive levels will generally produce better bulb life. Lower drive levels should also theoretically reduce the risk of bulb failure from physical shock. (No guarantees of course!)
Interesting food for thought. I guess its a balance for me if I am a flashaholic police officer or a police officer who is a flashaholic.

I really do appreciate all of your insight Eric. You make a hugely valid argument. I feel a little bit more comfortable thinking that the second light on my belt is going to be a Surefire M2 with an Oveready V3 Triple at the business end. FOR NOW, Im going to stick with my more dazzling criteria and if I find Im having issues Ill have the pack re-programed. While this still is a combat light for me, it is intended to be more of a search light first, which is why the MN61 works so well for what I am thinking as it has no heat concerns (well not none but less).

Looking at the destructive testing I would think that while these values are pushing the bulbs, they certainly could be pushed even further. Looking at DM51's M6 Shoot Out he actually ran the MN61 off of just a 3X17670 holder which I would think, even with voltage sage, would still be on the higher than my proposed settings. The other proposed bulbs also seem very resilient.

I mean no disrespect at all eric, I am not discounting your advice at all! Thank you again so much for all your insight.

Regards,

Stephen

5. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Hi Justin,

Originally Posted by Justin Case
So the denominator of the heat factor is not a constant since the series resistance divider will vary depending on bulb.
The denominator is a constant, not a variable. It is derived based on a 2C direct drive discharge. The same constant is used to formulate every "heat factor" rating.

That seems somewhat unusual since it would appear that instead of using an absolute reference value, you are using a variable reference. So a 1.0 heat factor for one bulb may not necessarily mean the same actual heat generation (say in watts) vs a 1.2 heat factor for some other bulb.
No

Also, I'm not sure I understand your rule of thumb that the amount of time to let the light cool down is given by multiplying the heat factor by the max continuous run time.

I would think that the cooling rate of the light would be essentially constant, independent of bulb (assuming other variables are held constant, such as ambient temp, air velocity, hand position on the light). So why would something like a 5761 have a shorter "cool down" time vs something like an 1160? Once the light heats up to whatever critical temperature is deemed to warrant shutting down, it would seem to me that the time to cool back down to some acceptable temperature is independent of the bulb. It's a constant heat capacity, and thus a constant amount of energy absorbed to reach the given recommended shutdown point.
I actually spent a few moments trying to decide what to "call" the specification, because "heat" really isn't the only factor ultimately being addressed by guidelines set forth by it. The name "heat factor" had such a nice ring to it. Hard to pass it up. The caveat was that I knew there would be one little bump in the road. Yes Justin, I thought of you at 2:47AM or whenever the heck in the middle of the night it was

1160 vs 5761 from the charts and recommendations:

1160: Run for 7.5 minutes, cool for 13.5 minutes, rinse, repeat.
User duty cycle = 56%.

5761: Run for 3 minutes, cool for 8.7 minutes, rinse, repeat.
User duty cycle = 34%

Convert to equal run time for each:

1160: run for 3 minutes, cool for 5.4 minutes
5761: run for 3 minutes, cool for 8.7 minutes

When each bulb is ON for the same amount of time, the more abusive bulb should be rested longer between runs.

You can convert down a bulb to a lower runtime, but do not convert up a bulb to a longer runtime. The important thing is the effective duty cycle of the user operation combined with never exceeding the maximum continuous run-time. If you have ever used a welder with a duty cycle rating this makes perfect sense.

If the term "heat factor" bothers anyone, just call it "cell abuse factor" instead.

Eric

6. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Troop#26
...........I mean no disrespect at all eric, I am not discounting your advice at all! Thank you again so much for all your insight.

Regards,

Stephen
Hi Stephen,

Absolutely no disrespect is taken!

If the M6 isn't necessarily going to operate as the primary light, but as part of an array of potential alternatives, then my comfort level with more intense drive levels for law enforcement certainly improves quite a bit. The drive levels you have in mind should be fine.

I'm a pretty paranoid type individual when it comes to personal safety/security against other mammals.

My only request is that you do some quick-draw practice on your illumination options!

Stay safe,

Regards,
Eric

7. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by mdocod
The denominator is a constant, not a variable. It is derived based on a 2C direct drive discharge. The same constant is used to formulate every "heat factor" rating.
Excellent.

Originally Posted by mdocod
1160 vs 5761 from the charts and recommendations:

1160: Run for 7.5 minutes, cool for 13.5 minutes, rinse, repeat.
User duty cycle = 56%.

5761: Run for 3 minutes, cool for 8.7 minutes, rinse, repeat.
User duty cycle = 34%

Convert to equal run time for each:

1160: run for 3 minutes, cool for 5.4 minutes
5761: run for 3 minutes, cool for 8.7 minutes

When each bulb is ON for the same amount of time, the more abusive bulb should be rested longer between runs.
I must be misunderstanding the application of your resting period equation.

The max continuous run time is not a constant and thus each bulb is not necessarily on for the same amount of time (which is what your 1160 and 5761 example above shows).

I would assume that the heat capacity of the 17670 cells is going to be constant for every user. Thus, to reach a particular temperature (e.g., 60C) above which you should shut down because the cells are getting too hot (thus dictating the max continuous run time), a fixed amount of heat is required to reach that temp. Hotter bulbs will reach this temp quicker than cooler bulbs (again, this is what your example above shows). But they all deliver the same fixed amount of energy to the cells to get them to the critical temp for shut down.

Similarly, the cooling rate of the cells and the M6 ought to be a constant for a given set of conditions. Thus, I still don't see why one should apparently wait a variable amount of time (your "resting period", which is given by max continuous run time multiplied by heat factor). Once the cells reach the critical temp (say 60C), the time to cool back down to some acceptable temp to start running again should be constant, independent of the bulb.

Your resting period formula could have the user turning on the flashlight sooner for hotter bulbs than for cooler bulbs, as shown by your example above. Why should one wait longer to let the light cool down when using an 1164 vs 5761? Isn't the cooling rate the same, regardless of bulb type?

8. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Updated bulb charts/tables from Eric:

PhDM6_bulb_chart_8_9_10.ods

PhDM6_bulb_chart_8_9_10.xls

9. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by mdocod
Hi Justin,

I honestly don't even want to try it. I've never exploded a bulb in my M6 and want to keep it that way if at all possible.

Eric
Originally Posted by Justin Case
I guess I was unclear. Has anyone tested the 1111 at 7.5V Level 3 in the PhD-M6? Or alternatively, at ~7.5V in a JM-PhD-D1 using Fast Soft Start. I've run the 1111 at 7.4V with a JimmyM regulator, but only at Medium Soft Start.
Originally Posted by DM51
You will be happy to know that with freshly charged cells, I set the PhD on 7.5V, the 1111 worked just fine. Also then repeatedly pushed thumb button, and it did fine.

Now, I'm not sure what actual voltage was being sent to the bulb with these aging cells, given the 4A battery chart I posted earlier...may very well have been direct driving at lower voltage, but it worked none-the-less. For what it's worth, AW did respond to my PM, and said that he was actually very impressed with the performance of those 3+ year old cells, given that it is nearly end of life. He said he could never recommend pushing these cells to 2C (above 3A) because it will result in less cycles and shortened life. You can tell he doesn't have that Incan Jockey "Crazy" gene.

10. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by LuxLuthor
You will be happy to know that with freshly charged cells, I set the PhD on 7.5V, the 1111 worked just fine. Also then repeatedly pushed thumb button, and it did fine.
I did the same with a 2D Mag11 mod using a JimmyM regulator set to 7.4V and fast soft start and loaded with 3xIMR26500. Repeatedly pressed the on-off button at various repetition rates and for various durations. No issues.

11. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Hi Justin,

The recommended continuous runs and the recommended resting periods are not based absolutely 100% on just heat generated in the cells. I wanted the recomendation to have the effect of producing more limited operating duty cycle on higher power lamps, and most importantly those lamps that are the most abusive to the cells.

If the battery pack and the head of the flashlight holding the bulb were thermally isolated from each-other, then you would be absolutely right that the cool down periods for the cells to cool off by themselves would be the same for every bulb, but that is not the case here, and I'm concerned about more than just cell temps in making these recommendations.

Keep in mind that the bulb introduces heat to the flashlight as well, so running something like an 1160 for 7.5 minutes straight will introduce more heat to the flashlight body than running the 5761 for 3 minutes, thus, a longer cool down period is required after that run.

I wanted to devise a simple calculation that anyone with elementary math could use to come up with some good guidelines to improve the safety of the operation of their flashlight. In using and testing the light for weeks and taking cell temps, I was actually amazed at how well the heat factor recommendation compared to my real world testing. Is it perfect? Nope. Is it pretty darn good? YES, I believe it is! You are free to use them, not use them, make your own, whatever makes you happy.

Eric

12. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

I guess I don't see why cool down rate is constant only if the battery pack and head are thermally isolated from each other.

If heat factor also may account for potential heat-related damage to the KT4 reflector (for example), in addition to 17670 cell heating, that still seems like you'd be dealing with a constant heat input to the flashlight system to reach that critical temperature to avoid heat-related damage/problems.

But it seems from your comments that a max continuous run time of 7.5min for an 1164 delivers more energy to the flashlight system than a max continuous run time of 3 min for a 5761.

Why would you allow more heat (and thus presumably a higher internal temp) to the flashlight system for one bulb vs another when determining max continuous run time? I don't understand that aspect.

13. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
Why would you allow more heat (and thus presumably a higher internal temp) to the flashlight system for one bulb vs another when determining max continuous run time? I don't understand that aspect.
Hi Justin,

The lower resistance load of the 5761 results in a higher percentage of expended energy being converted to heat within the cells than the 1164. That's what the specification "heat factor" figures out (as previously explained). So I suggest that a longer continuous run on the 1164 is reasonable.

We can't go around in circles on this forever. There are more pressing things, (like building PhD-M6 battery packs) to worry about

Eric

[edit in]
PS: Both the 5761 and 1164 are going to be very hard on cells and should not be used at all if you are concerned about cell health.

14. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by mdocod
Hi Justin,

The lower resistance load of the 5761 results in a higher percentage of expended energy being converted to heat within the cells than the 1164. That's what the specification "heat factor" figures out (as previously explained). So I suggest that a longer continuous run on the 1164 is reasonable.
I understand all of that. That's not the point. It is not relevant that one bulb delivers more heat per unit time than another. That relates to how long the "max continuous run time" might be. The faster the heat delivery, the faster the light reaches some undesirable high temp, at which time one should shut down the light, and thus the shorter the max continuous run time.

What I don't understand is why you would have a variable duration "rest period" that depends on the bulb.

I would have thought that you would want to shut down the light when the internal temp reaches some undesirable level. To reach that critical internal temp, the light bulb delivers some fixed amount of heat to the system. Depending on the rate of heat delivery, you get shorter or longer run time before hitting the critical temp. To then cool down to some acceptable level to allow running the light again also requires dissipating some other fixed amount of heat. Since the cooling rate is a constant, the "rest period" also should be a constant, not variable.

15. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Hi Justin,

The recommendations are not not based on hitting a particular temperature in every application, and they are not supposed to be. I would not want it this way for many reasons.

The recommendations are from the bigger picture of trying to preserve cell health when I know that some people are going to run configurations that are hard on cells. I've been using li-ion cells for years, done some of my own little abuse tests and have a pretty good feel for how to kill a li-ion cell in short order. Temperature is not the only factor.

If it were up to a lawyer, the chart would never have been made, we would just give a short list of lower power bulbs that are theoretically compatible with the PhD-M6 and back that up with a nice long disclaimer that ends with something like "for everything else, you're on your own, best of luck."

I decided to do what I believe the CPF community would prefer, which is to provide some recommendations to improve the safety during the operation of the flashlight when used with bulb options that push the envelope. I can't guarantee that following these recommendations will prevent a disaster, but I can sleep at night a little easier knowing that they should reduce the likelihood compared to making no recommendations.

I respect your right to disagree with any part of, or the entire premise of the recommendations. I stand by them as being well thought out and backed up by experience.

Eric

16. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

So other factors in estimating the max continuous run time could include how long you subject the cells to some level of high current draw and the resultant depth of discharge. Because of this, the heat input during the max continuous run time is not a constant because you are not using only some critical temp level in deteriming max continuous run time. And thus, one bulb could deliver more heat to the flashlight system during its max continous run time than another bulb during its different max continuous run time.

Does that capture the gist of it?

I guess I still don't see why the rest period duration is variable, and shorter for a more demanding bulb than a less demanding one.

My questions have zero to do with agreeing/disagreeing with your recommendations. One has to understand the basis for the recommendations first, before making an assessment of their utility. I'm at the understanding stage.

What is your normalizing value (i.e., the denominator) that you use for your heat factor?

17. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

The 4 domestic packs that I ship yesterday via USPS Priority mail should only take a few days to arrive within the USA (the two international ones of course will take longer). Once those packs arrive, please do post your impressions

18. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
So other factors in estimating the max continuous run time could include how long you subject the cells to some level of high current draw and the resultant depth of discharge. Because of this, the heat input during the max continuous run time is not a constant because you are not using only some critical temp level in deteriming max continuous run time. And thus, one bulb could deliver more heat to the flashlight system during its max continous run time than another bulb during its different max continuous run time.

Does that capture the gist of it?
Hi Justin,

Most LiCo cells are rated for a maximum 2C continuous discharge, and a maximum 140F operating temp. Would you agree that if one were going to exceed one of these specified maximums, that it would be beneficial to come in below the other maximum to theoretically offset the effective wear and tear?

If I run the IMR-M3T for the 15 minute maximum recommended run, the flashlight and the cells will be hotter than if I run the MN21 for 5 minutes. I don't want the cell temps to reach the level they reach when driving the IMR-M3T while driving the MN21 if I can help it because the MN21 is already very hard on the cells, I don't want to compound that with a lot of heat. The recomended rest after running the IMR-M3T for 15 minutes is about 20 minutes, and since a lot more heat will have built up in the light over that 15 minute run, 20 minutes to cool off again is a darn good estimation. Is it exact? No. The MN21 for 5 minutes will not have heated up nearly as much, so won't take as long to cool off. I'm estimating 11 minutes or so. Exact? well...... I used enough qualifier words in the chart.

I guess I still don't see why the rest period duration is variable, and shorter for a more demanding bulb than a less demanding one.

What is your normalizing value (i.e., the denominator) that you use for your heat factor?
Sorry. I'm not going to share any of the constants I used. As I said before, the denominator is derived based on the resistance of the cells. With that in mind, and realizing that the resistance of the cells is also used in every calculation of the circuit for every different bulb, that it doesn't actually matter that much what the denominator is, the chart would look basically the same even if a different denominator was used.

Eric

19. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
I did the same with a 2D Mag11 mod using a JimmyM regulator set to 7.4V and fast soft start and loaded with 3xIMR26500. Repeatedly pressed the on-off button at various repetition rates and for various durations. No issues.
BTW, You're welcome. I did that 7.5V 1111 just for you.

20. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by mdocod
Sorry. I'm not going to share any of the constants I used. As I said before, the denominator is derived based on the resistance of the cells. With that in mind, and realizing that the resistance of the cells is also used in every calculation of the circuit for every different bulb, that it doesn't actually matter that much what the denominator is, the chart would look basically the same even if a different denominator was used.
Oh come on. You gave us an example calculation for the 1111 bulb, which can be reproduced for any of the other bulbs. We also know from your PDF table that the IMR-M6 bulb has a heat factor of 1.0. Thus, if we calculate the waste heat generated by the IMR-M6, we get your normalizing factor.

I guess I'll just have to do the calculation myself and then post it.

Or even easier. Just take the 1111 calculation and divide by the 1111 heat factor.

21. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by LuxLuthor
BTW, You're welcome. I did that 7.5V 1111 just for you.
BTW, you're welcome. I did the Excel chart just for you.

22. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Any suggestions for approx voltage ranges for the MN10 and MN11 in a Z46? I can't recall for sure which LA I'm using, but I believe I'm driving an MN11 with 2xIMR16340 in an E2e host with a C2M adapter for the Z46. Is it really true that the MN10/MN15 and MN11/MN16 pairs use the same bulbs, just mounted on different towers?

23. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

I personally don't know for sure, but per this post, it sure looks like the MN10 = MN15 and the MN11=MN16, at least based on voltage, current draw, and power.

Popular bulbs current draw; SF & other brands, incl hotwires

Surefire Millenium Series 9V
MN10 M3 LOLA - 1.18-1.3A 9.5W (2x18500 67min/3x123A 1hr/2x17500 52min)
MN11 M3 HOLA - 2.50A 20W (2x18500 28min/3x123A 20min)
N2 (KT2 Turbo) - 1.21A 10W (2x186500 104min/2x17500 52min)
MN15 M3T LOLA- 1.10A 10W (2x18650 104min/2x18500 67min/2x17500 52min/3x123 1hr/M6 X-LOLA 2.5hrs)
MN16 M3T HOLA-2.54-2.65A 20.5W (2x186500 43min/2x18500 28min/3x123A 20min)
Surefire old style 12PM/ZM LeopardLight 3"T-62/TRTH or 2.5"SRTH Turbo "12V" light, 7.65V bulb
N 62 HOLA 7.65V - 3.70A (4xCR123A's 12min/3.35A on two 18650 Li-Ions/2xIMR16340)

24. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

I guess I'll just have to try it out.

BTW, when you hooked up your bench supply to the PhD-M6 for testing, where did you connect your power leads?

25. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
I guess I'll just have to try it out.

BTW, when you hooked up your bench supply to the PhD-M6 for testing, where did you connect your power leads?
I don't use a bench power supply to test the PhD-M6 - I only use the LiIon cells.

26. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Oh, I thought in your videos you powered the PhD-M6 with a bench supply.

Is power from a linear bench supply a bad idea?

27. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
Oh, I thought in your videos you powered the PhD-M6 with a bench supply.

Is power from a linear bench supply a bad idea?
During development I used a power supply, but the power supply does not behave like real cells do, so I use real cells for everything now.

Yes, using a bench supply is a really bad idea. The board was not designed for external access to signals/power. There is no easy nor safe way to do it. If you try it, it is highly likely to short something and kill the board - then the PhD-M6 becomes an expensive paper weight.

Have you used your pack yet? If so, what bulbs have you tried?

28. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Received my pack today.

First...build quality is outstanding. It matches the M6 quality, and that is saying something.

Fit in the M6 tube is perfect. No rattle not too snug.

Since my back yard is a 300 acre field I have a good place to shine lights
My MN61 did not come today so I decided to run the MN20.

Fully charged at 4.19v off the PIla I ran it about 25 minutes(all the darn insects I could take). My setting is 7.4 and this gave a beautiful white beam NEVER DIMMING. No heat issues at all.

Looks like the PhD-M6 is going to be superb. Tomorrow night the MN61 I hope. If not I will run the MN21.

29. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by wquiles
During development I used a power supply, but the power supply does not behave like real cells do, so I use real cells for everything now.

Yes, using a bench supply is a really bad idea. The board was not designed for external access to signals/power. There is no easy nor safe way to do it. If you try it, it is highly likely to short something and kill the board - then the PhD-M6 becomes an expensive paper weight.

Have you used your pack yet? If so, what bulbs have you tried?
I wasn't planning on powering the regulator at the board level. I had thought of hooking into the holder's battery contacts. But it doesn't seem to be worth the risk of "bricking" the PhD-M6.

I've used my FM MN bi pin adapter with a WA01274 at Level 3. Seems fine so far, but the testing so far has been very brief.

I noticed that if you put a non AC+DC RMS DMM onto the PhD-M6 holder's contacts, you get a voltage that seems to be lower than the expected OCV of the pack. Same with the tail current draw reading -- a lower reading than what you'd expect from Lux's tables.

30. ## Re: Feedback/impressions on the PhD-M6 custom battery pack

Originally Posted by Justin Case
I noticed that if you put a non AC+DC RMS DMM onto the PhD-M6 holder's contacts, you get a voltage that seems to be lower than the expected OCV of the pack. Same with the tail current draw reading -- a lower reading than what you'd expect from Lux's tables.
A non AC+DC RMS meter can't give you the correct values for the Vrms and the Irms. Most true RMS meters I have tried tend to give you a lower value, which matches what you are seeing.

Will

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