Electrical System Schematic

NOTE:  photos link to full size image

Here is my electrical system schematic. It is based largely on Bob Nuckolls' ideas published in his book, The AeroElectric Connection. It reflects my simple panel layout, and keeps the number of switches on the panel down to just the battery-alternator switch (used in place of a master switch), keyed ignition switch, and mag switch.

The picture is very large, and I recommend you right click and save it to your computer, then look it over or print it. Or, download the pdf file that may be more convenient.

Note: This first drafts of my electrical system had a flaw in the AeroVee magnetron wiring. The mags must not be connected together prior to the grounding switch (such as the key switch). If they are, the mags will ground out through each other, irregardless of the switch position, causing all sorts of problems. Some might suggest placing a diode in each kill wire as a "one-way valve", but the mags produce very high voltages and will likely overpower the diode rendering it ineffective. Possible solutions involve using relays on the mags (example (pdf)), eliminating the key switch completely, or moving the electronic ignition to a separate switch and placing one mag on "R" and the other on "L".

With all my electrical supplies on hand, I've begun to layout and fabricate my electrical system. First step is to get everything positioned on the panel where is doesn't interfere with something else, but still has good access to it.
I started with ground wires from the various engine components. Each wire gets a label and clear heat-shrink tubing, and will terminate via a Fast-On connector to a common grounding block.
The labels are made in a MS WORD document using 8 point font, then cut out and slipped under a short length of clear heat shrink tubing. The tubing is from B & C Specialty (along with all my other wiring supplies).
Although it adds a bit of time, the end result is a very neat and orderly wire bundle.
I chose to use 4 AWG wire for my battery and starter cables. Ends terminate into 1/4" copper ring terminals that must be soldered on with a torch. I drilled 2 small holes to allow soldier to wick fully into the wire.
Here is the general layout of my electrical components on the firewall.
The relays are on the far left, followed by the battery contactor, fuse block, and grounding block in the center, and the voltage regulator and ignition coils on the right.
A stainless steel firewall shield is placed over the cable pass thru grommet.
The inside of the firewall is getting a little busy with bolts and nuts.
Most of the Wiring is done at this point. I have bundled many of the wires together, but it is pretty difficult to get things looking really neat. :-( I'm happy for the most part with the layout, and it really does look messier in the pictures.
I am using this big heavy-duty capacitor to filter the regulator output. This should prevent any wayward spikes from reaching anything in my electrical system, as well as cut out any alternator noise in my headset. $20 from B&C Specialty.
The Odyssey 625 battery in the battery box. The plans dimensions were accurate for this battery, with just a bit of wiggle room.
The box is riveted up and the top strap installed. Ideally, this should have been done before installing the fuel tank to make riveting easier.
I am performing a full up electrical system test (without the battery). Everything works!


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Updated: 29 Jan 07