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Digging up an old thread....
I just converted an unused computer PSU to a 12Volt supply. Heaps of current capacity. Has built in under volts protection & over volts protection & current foldback. Although I suspect this foldback is set to a high current limit. It also has an inbuilt fan that cools according to load & heat.
Anyway...all I did was unsolder all the leads except the 12V & 0V, run this thru a fuse holder & to a Cigarette connector. Run a switch between the green & one of the blacks (power on).
Install a small load resistor...68ohms (to give the 12Volt rail a small load) between the 12V rail & 0V to load down the rail. This increases the saturation in the switchmode transformer so it's regulating better. I used a 10watt resistor & this is around 2W load. I installed this on the case so it sinks heat away.
Runs at 12Volts sweet! I really wanted 13.8V and on some computer PSUs you can adjust the 12V rail but on this one the Over volts kicked in when adjusting it up. I looked at the PWMIC specs but I couldn't get it right so I just left it at 12V.
Anyway a cheap alternate indeed!
Maybe I should do a write up as on mine I needed to re-solder 3.3V & 5V sense wires back onto the main board. There are guides on the internet though!
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