A little more than a year ago I built an 8x8 where two 4p8s groups were set top to top with insulation between. While this worked and was compact, it don't like the idea of depending on insulation between cell groups. Physical separation is more attractive.
Getting an idea or two from some Youtube videos, I used a different configuration. Most of the cells are end to end much like in an old D cell flashlight. Not end to end connected but just assembled that way. The result is that the top of one group and the bottom of the group above it are the same voltage point. The bottom of the stack, group #4 and group #5 are bridged with nickel strips. Cell groups are connected with nickel strips that stick out the side. Welded with Kweld brand welder.
Not shown, stranded fiberglass tape around it vertically reduces movement and takes any stress off the connection tabs. Will likely cover in a heat shrink tube.
Photo description:
PackTop, what each of the 4 pack tops looked like before adding the 10mm tabs to connect the packs.
BottomGroup4to5 shows cell groups 4 and 5 connection with 10mm strips, while inside each cell group, cells are connected with 8mm strips.
GroupToGroup-TabConnection shows setup ready for welding. Trying to weld without a backing surface was a bit of a pain but built a little spacer tower to help.
Stack, welded stack, waiting for the wiring to the BMS and positive terminal.
Getting an idea or two from some Youtube videos, I used a different configuration. Most of the cells are end to end much like in an old D cell flashlight. Not end to end connected but just assembled that way. The result is that the top of one group and the bottom of the group above it are the same voltage point. The bottom of the stack, group #4 and group #5 are bridged with nickel strips. Cell groups are connected with nickel strips that stick out the side. Welded with Kweld brand welder.
Not shown, stranded fiberglass tape around it vertically reduces movement and takes any stress off the connection tabs. Will likely cover in a heat shrink tube.
Photo description:
PackTop, what each of the 4 pack tops looked like before adding the 10mm tabs to connect the packs.
BottomGroup4to5 shows cell groups 4 and 5 connection with 10mm strips, while inside each cell group, cells are connected with 8mm strips.
GroupToGroup-TabConnection shows setup ready for welding. Trying to weld without a backing surface was a bit of a pain but built a little spacer tower to help.
Stack, welded stack, waiting for the wiring to the BMS and positive terminal.