Quote Originally Posted by circmand View Post
$29.95 at Pepboys but you needed to keep it charged as well. I do not see why you could not create a one way circuit that would allow a running motor to charge up a battery. Then have a switch that you could hit that if your car would not start would reverse the flow so the always charged battery could then jump the car.
sure, but then you would need a very large diode/very expensive battery isolator

same idea that they use for high end car audio, 2 batteries. but they dont cross signals, otherwise they would drain each other.