A common cause for an external battery powered machine to fail to start is a blown fuse on the battery cables.
The fuse can be found inside a black casing which is attached to the positive red cable.
The black casing can be difficult to open the first time. Opening it with a flat head screw driver can help.
Inside the casing you will find the fuse. The fuse is a 32V 15A blue mini blade fuse.
After opening the black casing, you will be able to see if the fuse has blown. The U-shaped wire will be broken and there will likely be a small amount of black char. The fuse is usually difficult to remove, so we suggest using a pair of pliers. Sometimes the break in the fuse wire might not be visible so if you have the spare fuse(more information in next step) replace the existing fuse with it to eliminate any doubts.
A replacement 32V 15A blue mini blade fuse can be found in the pocket inside your external battery bag (on the inside of the top flap) or they can be purchased at your local hardware store.
Your local Spinfire distributor can assist if you have any difficulties finding the correct fuse.
This video will show you the entire process of replacing a fuse: