Reliable Power Connections

The ubiquitous cigarette lighter plugs that most 12V equipment uses are very poor when it comes to making and keeping a power connection. A better type of connector would be the XLR connector which many people recognize as being the type used on microphones and other audio equipment. These have an added benefit of locking in place.

XLR plugs can be purchased that can handle up to 30A of current but for my needs a cheap plastic type suits fine. These come with solder lugs that will take up to 18ga wire. I put a bank of four panel-mount XLR connectors in a plastic project box and used the wire that delivered power to bank of cigarette lighter plugs to bring the 12V in.

Inside, the wiring is fairly simple. I stripped both leads for several centimeters and brought the positive along one side of the project case and the ground along the other. Then I brought a wire up from pin 1 of each plug to the positive 'rail' and soldered them in place. Same with the negative side which I wired to pin 2 of each plug. Then, so that I'd have an indication of whether the box was energized or not I put an LED into the top of the box wired with a 3900 ohm resistor.

I wanted to be able to move the power box from my 33Ah battery pack to my 12V power supply. To do this I used a two connector flat power plug. Look for these at any place that sells trailer wiring accessories.

That is about it for this project. I put Velcro on the back of the power box so that it could 'ride' on my battery pack or a leg of my tripod as seen in the image below left. This gives me 4 12v outputs for large currents such as the mount and anti-dew controller. Also, I have the single cigarette lighter connector to power my netbook (I'm not taking that adapter apart), a set of terminal lugs and some banana plugs on the rear. Good for just about any 12v need.

When I have access to 'shore power' I use a the Koolatron 5A power supply seen in the image below right. This is a very good unit with overcurrent and overtemp protection that provides enough power for everything I need to run. The netbook, or course, has it's own power supply that can be used.


Part Diagram

    From the diagram above you can see that I built power cables for all of my needs; the ST-4 which uses a DB9, mount and 5v supply which use different DC plugs and the anti-dew heat controller that uses banana plugs. Also, I put a female plug on the 2A Celestron power supply in case I needed to use it.

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