I know it works, but never understood how: Batt/Alt/Start

[Willie Krash]

I don't care which way it goes either Sparky.

The best way to deal with it is think plumping. Current is volume. A fire hydrant is a high current device. kids play in the water when they open them open. Voltage is push, the kids play as the volume is not being "pushed so much but raise the push/voltage it will knock the kids over and push them down the street. A squirt gun at it's pressure (voltage) and small volume (current) is harmless. Apply the squirt guns pressure to a fire hydrant and it can be lethal.
The battery is a filter or a condenser if you will. The generator is the pump to the battery, but like filling a tire you need higher pressure than what is in the tire. Like two tanks connected together, the tank with more water will feed the lower level.
This may seem an odd way to look at it but if you are unfamiliar with electricity you'd be surprised what you can do thinking of plumbing.
A bad connections is a clogged pipe. And open connection is I have water here in the pipe but not there so it's between the two points.
I hope I have not confused the issue.