Some Graphics Cards for desktop PCs require a lot of juice to work, sometimes even more than the PSU Power Supply can output. And if you decide to run dual monitors with dual Graphic Cards, then one Power Supply may not be enough. There are a few options to elevate this situation. Purchasing a new hefty PSU would result in a tidy but expensive solution. A more DIY-friendly and significantly less-expensive solution is to add a second PSU (which you probably have kicking around) and delicate the 2nd PSU to your Graphic Card(s).
There is one tricky part to doing this, the PC motherboard controls when the PSU turns on and off. This post will go over how to automatically turn on/off the 2nd PSU with the PC.
I’ve had the honor of mentoring a local High School’s FIRST Robotics team. Their robot runs on a 12vdc battery. During most of the testing, the robot doesn’t need to move too far, and watching the battery charge just seems like an unnecessary item to monitor. So, the alternative is to make a cheap, dedicated power supply.
This thing started off as an old discarded laptop(or similar device) power supply. It had a plug on it, emphasis on ‘had’. It got chopped in order to add a couple of binding posts. These bad boys will accept a bare wire or banana plug. I designed up a couple ‘caps’ and 3D printed them. They are pretty simple and made to fit a little snugly over the power supply. Eventually they will just be glued on to the power supply housing.