05-08-2004, 12:56 AM
I'm working on a car alarm set up in my house using a deep cycle battery and a trickle charger. The switches are radio shack magnetic type (circuit complete when the door or window is closed) wired through some Potter & Brumfield single pole double throw relays with a ground being the trigger to a Crimestopper alarm unit. The system worked well with a 12v. power supply but this left vulnerabilities if the power went out or was cut, so I went with the deep cycle battery. However the relays are hot to the touch after ten minutes is this normal or is this a fire hazard? Maybe a potentiometer to cut down on the power reaching the relays? Or would this just be a waste of energy?