thanar wrote: ↑
Jul 10, 2018 9:45 am
I don't think it makes a different which you do first, parallels or series connections; are you saying that the current having to go through an extra 0.15mm of nickel will add to the total resistance of the battery? By how much?
Frankly, I do the parallel strip first because it makes the whole pack much more robust and you need robust packs when putting together something for a vehicle. Series connections will be over each cell, not just one per cell-group as in the photo. The wires will be connected on three spots, in between the four cells.
Will upload more photos as soon as the extra strip I ordered arrives.
you are stacking welds for starters. the actual connection is pretty poor by comparison to a direct connection. plese bear in mind that battery resistance is measured in milliohms, so the series connections are a very important factor as those add up in series having 16S battery means you can have up to 16 crappy connections adding resistance. and resistance means more losses, higher voltage drop under load and poor performance. especially in high power and low cell count packs like this were every milliohm counts.
in many batteries the connections have more resistance then the actual cells. this causes heating, uneven balancing and is just bad practice in general.
the notion of pack rigidity is simply flase, the strength comes from the cell holders. you might want to put a dab of hot glue in the corner of 2 cells and the cell holder. that increases the rigidity even more.
it is also safer during constructon as any possilbe short is limited to the batteries you short, not the enitre parralel group.
also, if you extented the parrelel strip you could have all the balance wires on the side where they dont rub or get shorted....
just FYI: i build EV batteries for a living.
Lithium beats liquid dinosaurs.