"Race Car" Hot Wiring...help needed

What exactly are the "low voltage issues"? I Have a 77 Dodge plow truck and it seems like I'm having my share of problems too. I am having starting problems, seems like my battery doesn't have a full charge, even though it is new and usually hooked to a charger when I attempt to get it running.
It's got a few other issues to sort out, but it's really frustrating when I can't even get it started to tune it.