I've been making lithium packs and using nickel strip, but nickel is limited in what current it can handle. The higher current batteries i've been soldering 10-12awg wire, which provides no fuse protection.
I ran into this builder and it sparked an idea. I have very basic knowledge of PCB building.
They are spot welding nickel strip and using the nickel strip as the fuse. In this case it's a limit of 5a or so per cell.
In my case I have extremely high current cells. 30a continuous. It's difficult to stack that much nickel to support 30a.
What I would like to do is solder a 30a slow blow fuse one the board, and solder 12awg wire from the cell to the board.
Supporting 30a on the board.
I don't know how the above PCB is setup (whether it's just a solder mask, or whether it's a solder mask which connects to any layers of copper). It seems like the best way to go about making certain the board can support 30a of current is to connect the solder pads to 2 layers of copper. The size of the PCB is limited to 55x66mm, and each cell needs it's own individual connection to the PCB (on the positive, the negative can be a single track). That limits each pad to about 10x13mm, so I would want to have as many layers of copper as possible.
The positive connection (I don't think) is too concerning as, worst case, I can solder the lead directly to the fuse on the positive end.
The problem I am having is connecting the top and bottom copper to the solder pads. I receive an error stating "A connection between these two items already exists".
1. Is what I am trying to do the most "logical" (used loosely here) way to try to accomplish what I am doing?
2. Is it possible to connect dual (top and bottom) tracks to maximize current support?
Here is a top copper image. The middle copper pads with the first track is the "negative" end of the fuse. I will solder a 10-12awg lead from that track (haven't added a pad for it here yet) to connect to the next series of cells.
The bottom pad and track is where the negative leads will be soldered to the board from the cells.
When I try to add a bottom layer tracks, I receive the above-mentioned error "A connection between these two items already exists". Here is a picture of the error below:
3. How can I create a second hole within the pad to "beef up" the connection between the top and bottom layers? I worry the vias won't be able to support 30a, so i'd like to solder a large wire between the 2 layers. The main hole will be used to solder the fuse and/or battery.