I meant to give you a link.
Again, I’ve brought back batteries I thought were dead, dead, dead with this thing. Some I had to put a small charge on with an old school dumb charger so this thing would see the battery, and then go to town to work its magic.
Believe it or don’t but I actually have one of the Viking units.
They don’t keep the battery charged if they are in the drawer in the back of the van