Do more power supplies use more electricity?

[Bodega]

Perhaps this is a silly question, but I recently hooked up a second power supply (by CGS - it's good!) to about one half of my modular. So each of the two PSUs have about 200 mA on them.

What I'm wondering is: does running the same number of modules consume the same amount of electricity through one as through two?

My first assumption would be that a PSU that is connected to mains power but NOT to any modules would draw no electricity.

The second would be that all PSUs would draw equally.

Are these correct assumptions?

It might be nice to keep them on two separate PSUs, but not if it would cost me more money in the long run for, essentially, the same thing.

thanks!
Matthew

[richardc64]

The short answer is Yes, you'll be using slightly more electricity using two PSUs. This is because no power supply is 100% efficient. There'll always be a little bit more going in than coming out. The difference is dissipated as heat, mostly by the transformer, even with no load.

My guess is the increase -- if any -- in your electric bill will be minuscule. And there is one benefit: with the total load shared by two PSUs, they'll both run cooler and last longer!

[Bodega]

Awesome concise answer - thanks bud!