Can I wire two 12v atx connector together to get 24v? or the 12v and the 5v for 17v? I have a small amp board that I want to power with it. It's technically possible, but a really bad idea if you ...

I have a APC Back UPS PRO 1000.<BR><BR>The batteries died in it a few months ago and were recycled. I want to adapt this unit for use with a car battery for some testing. Of course the batter was not ...