Monday, August 31, 2009

110 V Power From Your Car Alternator

Back in the 1970's, there was a company that manufactured a product called "Pow-R-Tap". It was an easy to install device that allowed you to get 110V power directly from your vehicle's alternator.

Back then, vehicles had external voltage regulators. Today they are internal to the alternator. If you want to use this device on a vehicle with an internal regulator, you will need to make some modifications to the instructions I'm about to include in this post.

The instructions cover Dodge, GM, Ford and Leece-Neville Alternators with EXTERNAL VOLTAGE REGULATORS.

I don 't have access to information to the various configurations of internal regulators, so I won't be able to help you. However, an automotive electrician should be able to point you in the proper direction.

If you have an older vehicle that still uses an external regulator, it is a simple less than two hour job to install. You'll also need an evening to assemble the device since they are not (to my knowledge) available new. Don't worry, all you need are basic soldering skills.

I did quite a bit of research online and wasn't able to locate this device or its original manufacturer anywhere, so I think I am not infringing on anyone's rights. If I am, please let me know BY POSTING IN THE COMMENTS SECTION, and I will immediately remove this posting and all associated files.

I had one of these installed on a 1974 Suburban, and it worked well. It powered drills, and electric lights with ease. This does not generate a nice sine wave which many modern electronics need, so don't think about powering a TV or computer. It is a very rough square wave, but things like lights and electric impact wrenches don't care about sine waves.

At idle, the engine ran the drills at a slower speed than you are used to, and the lights were a little dim. Having someone manage the throttle, or adding an external throttle cable to manage engine speed solves this issue.

Fortunately, I'm a pack rat and kept the instructions and a home sketched diagram of the unit.

You will need 14 and 12 gauge stranded wire. Six feet should be good. Refer to the drawing to get the colors you will need to match up to the factory installation instructions.

You will also need a single crimp or solder spade lug connector

and a single crimp or solder ring terminal.

Liquid electrical tape.

Watertight Outlet Box.

120v 20A electrical outlet

Neon indicator lamp

0.1 mF 250V disc capacitor

SPDT Toggle Switch (12v/20A) Single Pole/Double Throw (On/ON)

Potting compound. (RTV silicone is good enough)

Electric drill and drill bits.

Soldering iron and solder.

Figure out where you intend to mount your homebrew Pow-R-Tap. Once you have selected where you want to mount the watertight box, you will know where to drill the holes for the toggle switch and neon light.

Drill the holes for the neon light and toggle switch.

If you are using a plastic weathertight box, you will need to add a ground wire to the ground lug on the electrical outlet. This will need to be attached to the frame of your vehicle. If you are using a metal weathertight box, the outlet will automatically be grounded to the box once you attach it with screws.

Assemble the device as shown in the diagram. The outlet and toggle switch are shown from the reverse (back) side. Solder the wires to the switch. Screws can become loose over time from vibration.

Seal all soldered wires and connections using the liquid electrical tape.

Install the device in the watertight box, and thread all the wires out through the hole for conduit. Before screwing the outlet into the box, fill the cavity in the box with the RTV compound. Be aware that some of the RTV will be displaced when you screw the outlet in place. Have a rag handy. Make sure the hole where the wires exit is also filled with RTV to prevent moisture from gaining entrance there.

The neon light will glow when you have the switch in the 110v position.

Now, I'm not making any warranties here. I expect that you should have knowledge of electrical safety, and knowledge of your vehicle's electrical system. If it doesn't work you're on your own. I know that this worked for me.

The PDFs of the instructions and the diagram are best printed out. The instructions have page numbers at the bottom. I encourage you to print them out, cut them into individual pages and assemble them in order to reduce confusion.

Page One Download Page Five Download

Page Two Download Page Six Download

Page Three Download Page Seven Download

Page Four Download Page Eight Download

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