In series:cooler, dont need bigger wire, dont require high drain battery
But can’t run if lack of 1 cell
Parallel: can run with any number of cell(technically, yeah, as long as your cell can handle the current), require thick wire, more loss of power
I still prefer series, especially when dealing with XHP led
One advantage of series is
The current run through all cells is equal
And in parallel, it depens on the cell’s internal resistor
Actually, it’s 1/16 as much. 1/4 the current means 1/4 the voltage drop. Losses are current * voltage drop.
That’s why high current is so hard: losses increase with the square of the current. The inverse is why we can transmit gigawatts over long distances with relatively small wires.
While this is partially true for the cells it is VERY true of the LED’s. This is why LED manufactures do not like parallel LED’s, they can have “thermal runaway” due to some LED’s getting more current then others.
Luckily with DTP stars this is not generally a problem with flashlights killing LED’s but it is not as efficient as it could be and with non-DTP stars I have killed more then a few LED’s due to running them in parallel.
Correct, this is true but I was trying to keep it simple for the laymen. The additive losses is indeed 1/16.
The end result is that high current is very hard to do and gets exponentially harder the more current there is.
This is why you have massive bus bars in high current applications to transfer power.
Question, I have 3 batteries in series and 3 LED’s in series, I’m seeing 7.25-7.35amps at the cap, depending on charge, what are my emitters seeing,
7,35 A since the current goes through all LED’s.
They just have no alternate route 
Yep, this is the correct answer. Which LED’s are you using?
Put me down for a second one
Series is more likely to run into battery management issues(of the flaming hover board type) so it’s not simply an efficiency issue and as yet there isn’t a buck or boost driver with anywhere near the output power of an FET driver. YET
You’re right, at somepoint
The maximum current of fet driver depends on voltage of battery, so to increase current, you need a higher voltage
This is where buck driver gains advantage, imagine you reduce from 12V to 4.3V, and assume your circuit can handle it. No single cell fet driver will as powerful as yours
This is not an issue in a flashlight which has the cells removed and charged individually. The issue stems from battery packs that are never balanced, the batteries get more and more unbalanced over time and eventually can lead to dead packs or overcharged cells. Although in most of those flaming situations the problem is cheap cells.
In a single discharge cycle it is virtually impossible for the cells to become unbalanced enough to cause an issue assuming they are even reasonably matched.
Although we don’t need a buck driver to run something like a Q8 in 4S mode, you simply run the LED’s in 4S as well.
A high powered buck driver is something that I would like to see but it will never match an FET driver in the power / space ratio.
Yep and I’m seeing instant BLUE! In TURBO!!! 
Some emitters just can’t take 7+ amps!!!
Might as well announce this here. I feel this thread has been a big part of my life as of late...
It's official, I'm a grand-dad for the first time!
Rebecca - 7 lbs 4oz 
Mom and daughter doing fine
Congratulations Tom!
I’ve got to admit, it almost feels like family here!
Beautiful name, my daughter her second name is Rebecca as well 
Hahaa! :+1: Grand Pa!! Congrats!!! 
Congratulations Tom! I hear good stories of being a grandfather, the benefits of children without the sorrows and such
Congratulations Tom :+1:
I have 5 grandsons, so far
Congratulations
Beautiful name
Dear Miller, could you put me down for an extra Q8, I have a friend who wants to have one for owl-spotting on rocky slopes, the Q8 may just have the perfect combination of output, flood/throw, tint and runtime.