Thread: Portable jump starters, any good

I saw a new one advertised in one of the farming rags that comes out that’s small, but does most size motors. You hook it up, start the engine, leave it hooked up for 45 seconds and that recharges it ready for next time. Some new type of battery that handles rapid charging.
I’ve tried to find it again, but is placed somewhere safe. Can’t for the life of me remember who carried them, or who made them. Would be worth a few bucks, but in theory should be good to go every time.