This is a 300A ANL fuse to protect the Spot Welder in case of a failure.
What you get:
- ANL 300A fuse
Why using a fuse ?
If you want to power the Spot Welder with a Lipo battery it is recommended to use a fuse on the positive welding cable. In case the Spot Welder should fail and cause a short circuit and for whatever reason you would not be able to seperate the welding tips this will prevent the lipo battery from burning down your house or exploding. When using a car battery it is not necessary to add the fuse but it can still be installed to enhance the safety in case of a failure.
A 300A fuse works well and can handle higher currents for a short time. I did arround 1000 test welds without a problem.
When connected to a Lipo battery you need to isolate the fuse. Easiest solution would be to wrap it in electrical tape. But a 3d printed case looks much cleaner. (STL files for the case)