Thursday, July 2, 2009

Automatic 12VDC Power Source Switcher Box for Solar Power Backup

Design - 12V DC Backup Power auto switcher for Solar Powered backup system

Use - I am using this to keep continuous power to important devices in case of power outage.

Example Devices: Smoke Detectors, Security System, Network Router, Network Server / Switches, and home automation control center
(Note: all of these run on 12V, or run on a voltage that I am going to adapt from 12V such as 9V)

I have settled on my final design for this device. I chose the design for it's simplicity, affordability, safety, and functionality. I ordered the parts which cost me less than $30 before tax and shipping costs. I will include a parts list and schematic.

Input #1: 12V DC from Solar powered battery backup system
Input #2: 12V DC from a 110VAC to 12VDC Power Adapter (Suggest 5A Current Rating)
Output: 12V DC (5A Max) - Supplied from AC when available, automatically switched to solar powered backup battery source without interruption in case of power outage.

A Green LED will light to indicate the unit is powered by the 12VDC from the AC Adapter.
A RED LED will light to indicate the unit has switched to and is being powered by the 12V DC Backup System

Parts List:
Relay: Relay1 = Z988-ND - 12V Relay 8A SPDT NC

Power Diode: D1, D1 = 6A2-TPMSCT-ND - 6A 200V Rectifier Diode (To provide isolation)

LED Indicator: D3 (Red) = 67-1067-ND - Red 12V LED 3MM

LED Indicator: D4 (Green) = 67-1061-ND - Green 12V LED 3MM

Capacitor: C1 = P5142-ND - 16V 1000uF Radial

Power Connectors: (Optional) CP-011B-ND - 5.5/2.5mm O/ID DC Power Jack Panel Mount

Power Cable Ends: (Optional) CP-2184-ND - 5.5/2.5mm O/ID DC Power Cable End

Parts available from:

Wednesday, July 1, 2009

12V Power Source Auto Switcher

I am looking to build a box that automatically switches over the power source from an AC Supplied 12VDC power supply... To my 12V Solar backup battery. The Box would act like a UPS, in that it would normally be supplying voltage from a 12V wall plug, and automatically switch to my Backup Power Source in the event of a power outage.

I am thinking Diodes, (for power isolation) Capacitor, (For Buffering the power during the source switch) Relay to switch... Etc. Any suggestions would be welcomed.
I have a schematic in my head, and I'll post my thoughts as I brainstorm more.

I want a low current Relay that will swap over to the other source when the power goes out.
12V powered, and capable of handling 5A or so max.

Monday, April 13, 2009

Electronics Projects

This blog is to journal My Electronics projects / ideas. Please contact me if you wish to submit info or a project plan.