I'm ready to hook up some power to the Mercedes window lift motor I'm using to open my monsterized sliding glass door, and now I need an affordable power supply.
I attempted to determine the power requirements with my own car ...
I removed the 40A fuse and put my ammeter in line, then turned on the ignition switch. I got a drain of about 1.5 to 2A. Then I ran the window lift and it ran up to 7 to 9A, so I guess it's drawing about 7A without major load. Then I kept the window switch activated after the window was closed, and the meter over-ranged at its 10A max. So, I'm thinking 20A should be enough.
I can buy a 12V/25A power supply from Radioshack for $100, but I'm wondering if there's a more cost effective solution.
For example, I can get auto jumpstarters for $30 to $60 that are rated at
300A/7AHr to 600A/22AHr for starting, but have a 12V jack for powering accessories and a 110V charger to charge them. Would these be a reasonable alternative? Could I leave one of these plugged into 110V all the time?How about an auto battery speed charger rated at 25A for $60?
I've seen a 6A 110VAC/12VDC converter for $25. It's been too long since I did these kinds of calcs ... would that be ...
6A x 110V = 660W = 12V x 55A?Or would it be 6A at any voltage with the wattage varying?
Any advice or alternatives would be appreciated.
Also, how do I select a relay to drive the motor from the Stamp?
Thanks, Bruce