I already have and use a battery tender but have a friend who swears that all I needed to do was connect a 12v 1.5A DC power supply (I had one on the bench that he had noticed) to the battery and it would work also. I could see it charging but there is no way to make it stop charging once the battery is at capacity. Thoughts?
Yeah, without the ability to shut off when the battery reaches full charge, you risk frying your battery with a constant charge to it. That's why all of the decent tenders have that circuit.
