Need a good 12v / 5v / 3.3v power supply for projects? A 400 watt supply can provide about 23 amps at 12.5 vdc or so. If you have an old computer supply laying around, you may be all set. New ones are about $18-$25 (https://amzn.to/2Xiu3c8). Mike McRoberts has a great instructional on the conversion process.