DC Power Management

The Beautiful Golden CO Model Railroad

12 Volt DC Power Bus Management

The other night I was working on the layout connecting a device to the 12 volt DC power bus I have on my new layout. Soon I smelled something electrical over heating. I immediately shut'er down. I knew where the problem was and was able to fix it easily. Then I began to think that there needs to be a over load/short circuit protector. I have my track power fully protected but not my 12 volt DC Bus. I thought of putting a automobile light in series in the circuit which will "light up" if too much current is being drawn through the circuit. Then I remembered I had a DC Amp meter laying around too. So I designed a 12 Volt DC Power Management panel with a power switch, amp meter, and an current over draw/short circuit light.

The DC Power Manager.


There are a lot of uses for 12 volts on a layout. I do not want to draw the 12 volts from my DCC system so I set up an independent 12 volt power supply. I want a supply that will give me about 8 amps which I hope will be plenty of current to run the devices such as switch machines, building lights, and other 12 volt things I will eventually add to the layout. I have about 11 amps of total available but I will not want to draw more than 8. My amp meter goes up to 10 amps so I should be able to monitor the amperage I use (The switch above the DC Power pael is the Master'; AC Switch).

The Hay Wire.


I bring the both the positive and negetive 12 volts into the panel. Most of the ciruit is on the positive side. It first goes to a pwer switch. I have a green led on top of that which indicates that I have power. The negative side of the led goes to the negetive terminal. The current then goes to the amp meter and then to a positive "out terminal. I use the "European" style terminals which allows secure bare wire binding. I put a electrolytic 220 mirofarad capacitor across the positive output and the negative to "clean up" the DC voltage from any left over AC sine wave. The capacitor may be a little too large as it adds a "momentum" effect of a few seconds to the shutdown.


Devices using the 12 volt Bus.

DC Power Eaters

Here are two devices that draw 12 volts from the bus.

The Power Supplies

The DC Power Supplies

Here is a view of the power supplies. I have an old battery charger along with two 12 volt 3.3 power supplies I got from All Electronics on sale. These are all connected in parallel so that the voltage remainds 12 volts but the amperage is added together.