I've seen the posts about building an IVR using a linear 7805 regulator and I know you can buy them for $60 USD specifically for our cars. I was looking for the components then found that you can buy assembled generic units for $20 or so. Of course that made me wonder why nobody was doing that and perhaps there was a good reason. I was looking at the rated wattage of these units and many are in the 15 - 25W range. What is required? The 7805 is rated for 1.5 amps x 12 volts which is 18 W (I think?). I have no idea what the current draw is on a rallye cluster although I read that it has a 3 or 4.5 amp fuse. Is a 15W unit adequate or does it matter as long as it has a heat sink?















