Actually, I think it is kind of helpful for people that aren’t familiar with circuits. I might use it to explain some things to my wife….
But it is still a bad analogy because the batteries actually help each other when run in series, each cell taking less load by dividing it up between em.
If I stand on djozz’s shoulders he’s got my 200 lbs as well as the mantle to support. Yeah, probably not what he want’s to think about.
A Diesel engine in a pick-up has very high compression and requires a lot of power to turn over when cold. They use 2 car batteries in parallel for the added capacity, which maintains the 12V system but gives much more cranking amps. Our lights are the same process, a Courui has 3 cells in parallel that don’t sag as much because they’re sharing the load to the single emitter. Same Voltage, but triple the capacity.
The BTU Shocker is a triple that has 3 cells in series, maintaining the capacity of a single cell but tripling the voltage to the 3 emitters also run in series. This allows the voltage to match the emitters once again, but because the voltage is tripled the capacity stays the same as one cell.
Ok, so it kinda get’s complicated while being inherently simple. 
Now, how can I shove a pair of Efest Purple 26650’s into the BTU Shocker? Voltage AND capacity. Maybe if I hammer em a little flatter…
Yeah but my wife doesn’t think about how heavy “flashlight-forum Dale” is 
And she knows even less about diesel engines.
The beams should be parallel, each spreading so they overlap more as distance increases. Orientation won't matter if each beam is perfectly circular. I haven't seen one in the flesh yet, though.
I wasnt picking on the analogy, just clowning around.
But I would assume that amps supplied from each cell in parallel set ups is lower from each cell compared to singular or in series too (effectively a single albeit higher voltage battery). So in this emitters case, it might be wise to include parallel into the battery config to reduce load on each cell used, given most will use series and series being the most dangerous config for Li ion?
The beam has a plus sign in the middle, just like the emitter. 3 of those gives a more defined plus sign if they’re aligned. With each turned to oppose the other, this is reduced as much as possible.
I have 8 running, one single is blended with a Minnie-M reflector in an X6. The other is in a Shadow JM26 running off a single 26650 (courtesy of the driver intended for a DQG Tiny Triple).
I’m worried about the use of 8 18350’s, so I’m working on a solution to use 2S2P 18650’s in the SupFire M6. I’m building this for a friend and don’t want him blown up! lol
I was under the impression that multiple TIR optics did a better job of blending than multiple reflectors but maybe multiple OP’s would be just as good.
Your right, it’s a confusing way to put it, but if I stand on my head and peek out my ear it makes sense.
It’s another way to illustrate how much less power is available from 2 x XX350 than from 1 x XX650 and since we know that certain members have an odd point of view this may be more clear than another method of description. Sort of like looking at a 2D image of a cube and inverting it with your minds eye. If you can wrap your head around several different perspectives of the same thing you probably have it pretty well conceptualized.
Cells in series always increase voltage, not amperage. Cells in parallel always increase amperage, not voltage. Cells in series/parallel increase voltage and amperage.
Have you noticed that the cells in series do not draw down the same? I have found that in my HD2010 with 2x18350 in series, that the back cell is always much hotter than the front cell and that it always takes longer to charge. I have six cells and use two at a time. I can mix and match any way I want, but whichever cell is in the back, is always depleted much more than the front cell.
Now, from my non-electronic background, I wonder why the front cell is not hotter. I thought it would be, since not only is it giving current, but the cell behind is giving current into it. It is the opposite though. The rear cell sees more stress. Why is that?
I see more of a difference between cells used in a series setup than a parallel setup. If all cells in a parallel setup are the balanced and the resistance is the same in each parallel circuit, the cells discharge almost exactly the same, but never that way in series.
Then comes the real problem circuit. Series/Parallel. If you want to ask for trouble without trying, then Series/Parallel has to be the worst of all circuits for Li-ion batteries. All of the cells are going to try to equalize and if one is weak, then the lowest resistance cells out of the others, are going to dump fast trying to equalize the circuit. Especially when idiots like me try to run 30 or 40 amps thru 2S/4P. I really can't believe I keep doing that, but I do.
I always use new cells and matched cells and "good brand name" cells that take high discharge rates, but it still concerns me.
From my limited electronics know-how, I think the current flow is from negative to positive.
Still, you’d expect both cells to be equal :~
I can’t think of any other reason for the 2 cells to be different, other than perhaps more resistance in the tail spring or cell to cell resistance. If the front of the light doesn’t get too hot, it could provide more heatsinking to the front cell as the 2 cells heat up with use.
Of course it could just be that your rear cell has more internal resistance.
I expect that the cell that's getting hotter will drain at a different rate.
He mentions he has 6 cells, and can swap them round and round, result is the same.
I think I answered how the rear cell could get hotter in the first place, what I can’t explain is why it would drain faster than the front cell that runs cooler. All of the electrons that flow out of the rear cell would also flow through the front cell. So any extra drain would have to be internal to the rear cell, as sort of a self discharge. And I suppose that could be because of it’s higher temperature. I just can’t imagine that the effect would be noticable.
Also being at a slightly higher temperature, it wouldn’t be as thermodynamically efficient?
I think it is quite impossible that two cells in series that experience the same current do not produce the same amount of heat. Voltages of two cells that have been in series are also always the same in my experience.
Perhaps the rear cell receives the heat from the tail spring. If steel springs are used, with the currents OL is using, they are quite capable heat generators. (but I assume the presence of a driver spring as well, and there the effect should be just the same I guess)
I already considered heat from the tail connection. The temperature can come about 1 of 3 ways.
Extra heat generated at contact points.
Heat that IS generated not being dissipated as well.
Extra internal resistance inside the rear cell.
As far as internal resistance goes, there is a positive feedback mechanism here.j As the cell heats up, the internal resistance would increase even more causing even more heat etc.
This is an interesting phenomenon, and I can’t quite explain it.
dchomak, the rear cell's resistance has already been ruled out as a variable. Old-lumens said that he's swapped the cells around and seen the same result. That leaves heat production from an external source which then heats the cell.
Ending up with 0.1v or 0.2v difference isn't going to blow anything up in one of these lights. I should be wary of making categorical statements, but I personally would not worry about it. I always measure differences in voltage with series cells. This is bound to happen, no matter how closely matched the cells are.
What is dangerous is putting two different cells together then pushing them hard, or having one cell in the series that is continuously getting farther apart from the rest (we avoid this by "balance charging" the cells outside of the light), or having an empty cell in series with full cells. A slight difference won't blow anything up, especially with a direct drive driver or linear driver because the current gets lower as the cells drain.
It's a HD2010 with an MT-G2, Qlite 3 amp driver, zener mod. Springs have copper braid, resistance is not an issue for the springs. Might be for the switch, but I have never seen anything that flows from negative to positive. Always from Positive to negative. Of course, that was all automotive, but how would even a DC circuit work, if the current flowed from negative to positive, instead of the other way? I understand a 7135 driver regulated via negative, but does that mean the whole light is running in reverse from a normal DC circuit?
Probably not a good thread to discuss this in, since it's going to get away from the original topic.
OL, I know this will blow your mind, but electrons flow from negative to positive and conventional current flows from positive to negative. :bigsmile:
EDIT: