alpmco
05-12-2011, 02:14 PM
As some here know, I putz around with amateur radio. I took an interest in communications back when I was about 11 years old. I discovered a radio station one night out of North Carolina (I live in Florida) that was playing episodes of the CBS radio Mystery Theater. A couple years later I put together a Radio shack short wave kit and discovered shortwave broadcast and utility radios stations. Then I discovered military communications.
So part of my requirements over the years has been to keep in touch with the outside world in the event of some disaster. Most amateur radio equipment runs off of 12VDC as a standard and so wiring the house with 12VDC seemed logical when I added on.
Let me warn you now of something I was not aware of when I began this project. DC power is not like AC power. DC power requires larger gauge wire. AC Power runs along the skin surface of the conductor where DC flows through the conductor and therefore it encounter a lot of resistance. I used 12 gauge wire for my wiring behind the wall and initially had my batter supply in a nice rack in the garage. Unfortunately after making the 28 foot run to up the wall, over the rafters and back down the wall to the terminal block that I powered the radios off of, the voltage dropped about 2 volts under load. In hindsight I should have used at least 8ga wire. Best laid plans scuttled by ignorance and carelessness.
All is not lost. I had two runs off the batter supply, on the to office / radio shack and the other to the master bedroom. When I moved the batteries I simply spliced the two wire runs together so after the battery move I would still have low amperage power to the master bedroom. That is all I needed to run up to a 400 watt power inverter upstairs.
So the solution to my wiring problem was to move the battery supply as close to my high demand equipment as possible. I built a battery box capable of holding at least two deep cycle wet cell batteries. From there I ran 8ga cable out a conduit then underground and plumbed it trough the wall and spliced it into heavier terminal blocks. From the block the DC power runs through the old circuit to the master bedroom and the radios, a 600 watt AC inverter and lamp run off the block too.
All the radio equipment runs off 12VDC. The invert will run a fan and a laptop. If necessary it can run the desktop computer and printer. If I’m desperate and the cable is up it will also power the cable modem so I can access the internet. Chances are if the power grid is down the only thing that will work is the old Ma’Bell telephone. No way will I replace my old twin lead telephone. Those systems are nuclear bomb resistant!
To keep the two batteries charged I have a marine type battery charger. It is supposed to be a smart charger and keep the batteries charged without letting them sulfate. The down side of the charge is it get noisy and interferes with the radios (QRM) when it kicks in to higher charge rates. To solve this I have a remote control on off switch that is sold at Christmas time to turn on and off the Christmas decorations from inside the house. I have that on the AC line to the charger and can turn the power off from my desk and turn it back on when I am done putzing with the radios. Eventually I want to replace this charging system with solar panel on the roof of the house.
Here are some photos of the outside enclosure. Not much to see or take photos of inside as it is mostly behind the drywall and hidden out of sight. I’ll have to get a photo of the desk area and the equipment that is running off the power supply.
http://img.photobucket.com/albums/v167/alpmco/iPhone/c2118603.jpg http://img.photobucket.com/albums/v167/alpmco/iPhone/7a2f5bc1.jpg http://img.photobucket.com/albums/v167/alpmco/iPhone/bc86219c.jpg
So part of my requirements over the years has been to keep in touch with the outside world in the event of some disaster. Most amateur radio equipment runs off of 12VDC as a standard and so wiring the house with 12VDC seemed logical when I added on.
Let me warn you now of something I was not aware of when I began this project. DC power is not like AC power. DC power requires larger gauge wire. AC Power runs along the skin surface of the conductor where DC flows through the conductor and therefore it encounter a lot of resistance. I used 12 gauge wire for my wiring behind the wall and initially had my batter supply in a nice rack in the garage. Unfortunately after making the 28 foot run to up the wall, over the rafters and back down the wall to the terminal block that I powered the radios off of, the voltage dropped about 2 volts under load. In hindsight I should have used at least 8ga wire. Best laid plans scuttled by ignorance and carelessness.
All is not lost. I had two runs off the batter supply, on the to office / radio shack and the other to the master bedroom. When I moved the batteries I simply spliced the two wire runs together so after the battery move I would still have low amperage power to the master bedroom. That is all I needed to run up to a 400 watt power inverter upstairs.
So the solution to my wiring problem was to move the battery supply as close to my high demand equipment as possible. I built a battery box capable of holding at least two deep cycle wet cell batteries. From there I ran 8ga cable out a conduit then underground and plumbed it trough the wall and spliced it into heavier terminal blocks. From the block the DC power runs through the old circuit to the master bedroom and the radios, a 600 watt AC inverter and lamp run off the block too.
All the radio equipment runs off 12VDC. The invert will run a fan and a laptop. If necessary it can run the desktop computer and printer. If I’m desperate and the cable is up it will also power the cable modem so I can access the internet. Chances are if the power grid is down the only thing that will work is the old Ma’Bell telephone. No way will I replace my old twin lead telephone. Those systems are nuclear bomb resistant!
To keep the two batteries charged I have a marine type battery charger. It is supposed to be a smart charger and keep the batteries charged without letting them sulfate. The down side of the charge is it get noisy and interferes with the radios (QRM) when it kicks in to higher charge rates. To solve this I have a remote control on off switch that is sold at Christmas time to turn on and off the Christmas decorations from inside the house. I have that on the AC line to the charger and can turn the power off from my desk and turn it back on when I am done putzing with the radios. Eventually I want to replace this charging system with solar panel on the roof of the house.
Here are some photos of the outside enclosure. Not much to see or take photos of inside as it is mostly behind the drywall and hidden out of sight. I’ll have to get a photo of the desk area and the equipment that is running off the power supply.
http://img.photobucket.com/albums/v167/alpmco/iPhone/c2118603.jpg http://img.photobucket.com/albums/v167/alpmco/iPhone/7a2f5bc1.jpg http://img.photobucket.com/albums/v167/alpmco/iPhone/bc86219c.jpg