Powering my 650 sq ft layout??

The 180's are great for track power.

Then, one needs to estimate the amperage requirement for the equipment that will be used.

Theoretically, one is enough until you approach 8 or 9 amps of current draw. So, two would be good.

Finally, accessory power needs should be determined. I like the Z-1000 with the fixed 14v AC terminals. You may need 12v DC power, also. I like HO train transformers for that and the adjustable voltage modules available on eBay to lower the 12v bus for specific applications.

What would the 12v DC power be used for?

GJP posted:

What would the 12v DC power be used for?

Led lighting ( with variable voltage reduction boards), relays, relays with timers, sensor or control devices, building sound devices - and anything else that folks cobble together.

Light every structure with LEDs. Street lights. Control relays for Tortoise switch machines and power indicator LED on control panel. and so on...

That makes sense. I didn't think of LED because my lighting  (from Evans Designs) just hooks right up to the accessories post of my ZW transformer. 

GJP posted:

That makes sense. I didn't think of LED because my lighting  (from Evans Designs) just hooks right up to the accessories post of my ZW transformer. 

Cheaper to eBay the LEDs of various types and colors and drive them directly with the proper voltage. Powering relays to control AC is also sweet. lets one use small switches or controls.

layout control and animation can all be accomplished with 12v DC and inexpensive modules and such off of eBay.

I prefer to keep AC track power, AC accessory power and DC powered devices on separate sources. As you know, there are many ways to get it done.

I think Moonman has described everything pretty well here, follow his advice and you should be good. 

IMO, the PH-180s are the best and most economical way to power a layout. They also have very good and fast breakers in them.