Aircraft Re-Wire Using Dynon Gear Help Needed!!!


I love flying!<br />
Mar 5, 2016
Hi All,

New to homebuilt airplanes, new to this forum, and new to Dynon.

I purchased a Velocity aircraft that is currently equipped with one Dynon Skyview EFIS system, dual plasma III ignition systems, a belt driven alternator, an accessory pad driven alternator, two LR3C-14 Voltage Regulators, and two batteries, and a number of diodes to cross power between the two electrical busses, the usual master switch, master avionics switch, taxi light, landing light, navigation lights, strobe, hydraulic gear pump, and interior lights.

I want to really clean up the system and redo the panel to get rid of pretty much all of the old school boat anchors avionics, add a second Dynon 10 inch screen with ADCAHRS, a Dynon transponder, a Dynon ADS-B unit, a Dynon radio, a Dynon autopilot controller head, (it already has the two axis autopilot).  The only non-Dynon avionics will be a Garmin 430W, a SL-15 COM panel, and a SL-30 NAV COM. 

With this clean up I really do not want to have to splice and dice wires so I want to essentially do a rewire of the system.

This seems to me to be a very common system and naturally I want do not want to reinvent the wheel and therefore would like to ask the advice of the the knowledgeable guys on this forum so that I do not re-live someone else's past mistakes or their "Shoulda...woulda...couldas".

I would like to set up the system to be redundant to allow each PLASMA ignition and each side Dynon display (and ADSAHRS) to have an independent source of power and also use diodes to be able to power both busses should its associated side alternator fail.

So here are the questions:

-Has anyone built a similar system and would like to throw me a schematic?

-I know I want a main bus and a secondary bus with diodes connecting the two.  Do I want a hot battery bus for the Plasma and the Dynon?

-The Dynon will have an autopilot system so do I still want an autopilot servo power shutoff switch (a panic switch that will be left in the on position 100 percent of the time and only placed in the off position when the autopilot system is acting up) or is the stick mounted push to cancel protection enough?

-Since the Dynon will be my only source of of engine instruments during engine start ,so do I need the pilot side display powered separately from the other avionics or should it be wired directly to the battery bus (or hot battery bus) other words, the left side Dynon and the Prinston fuel probes are powered when the battery master is turned on and then after engine start the avionics master is switched on and then the Garmin, comm panel, second Dynon screen/system are turned on? 

-Looking through the Dynon Installation Manual it seems that all of the ancillary Dynon gear (auto pilot servos, transponder, ADS-B) is powered by the Dynon Skyview display through the network cable and each unit does not have it's own power supply.  If this is the case then I only want one Dynon powered during engine start.

-The airplane currently has one load meter and since I will be using the Dynon as the only monitoring system I am wondering if I still want an amp meter indication or would the simple two system voltage indicators be sufficient and then I can get rid of the shunt and it's extra connections?

Anyhoo...there is really more to it than I am thinking now so any help would be GREATLY Appreciated!!!



New Member
Dec 2, 2011
Jacksonville, FL
Go to, click on catalog of products and services, scroll down, buy a copy of the Aero Electric Connection, and start reading. You will find everything you need there.


Active Member
Aug 22, 2007
Based on your comments I recommend you find a local builder that can help you.

One specific comment however. I note with concern your thought about having your LightSpeed ignitions on the same buss as other equipment. As the LightSpeed does not have it's own power (like eMag) you need to have a bullet proof power distribution design to protect them.

What you want to do has little with upgrading your Dynon install so a local builder (of any kind of airplane) to unravel what you have is a good first step.



I love flying!<br />
Mar 5, 2016
Thanks for the feedback thus far!!!

Yes I have downloaded and mostly read the Aero Electric Connection. Very good info. Does not address my specific a matter of fact, reading that book prompted the questions.

Yes I completely agree about the dual Plasmas not being connected to the same bus...and THANKS you for your suggestion. I have read the Plasma Instruction manual a s well and they require the Plasma being connected directly to the battery +/-

So still have a bunch of questions...any additional feedback would be great!!!


I love flying!
Nov 25, 2013
I would also like to throw my two cents in for what it's worth:

I have a fairly similar general setup--two alternators, two batteries, and my engine requires electricity to run.

I decided to keep the electrical systems completely independent, inspired by commercial jet design.  I do have a cross tie circuit breaker should I need it, but the general intention is to never touch it and have each bus capable of flying the aircraft safely for my average missions.

One of the reasons I went this way is diodes are a little more difficult to execute than you imagine.  You're going to make a bunch of heat if you have a diode handling any reasonable amount of continuous current, there's always a voltage drop, and your systems are still linked together for certain failure modes (like an overvolt).

The downside to independent systems is you need a second power source, which you already have covered and it sounds like you're not getting rid of it.

About your other questions:

As for autopilot servo power, I spent a lot of time thinking about this one and ended up without a power kill switch.  I feel comfortable with Dynon's servo design, and I figured I can physically override the servos for long enough to get to the circuit breaker.

There are a couple of ways to tackle engine instruments during start. One thought is to install the Dynon backup battery and just use it while starting if you don't want to power everything else up. The opposite end of the spectrum is where I ended up--I just have a master switch, and everything is powered during start.

I monitor volts and amps for both electrical systems (and I'm glad I do).  Dynon makes doing this a little complicated--I have the Dynon shunt on one side, and a GRT hall effect sensor (CS-02) on the other.  While you can display both ammeters, there is a software bug that only allows one of them to show up in the data logs.  Click here for the thread on that--the bug has been known about since 2013.

Best of luck!


New Member
Oct 2, 2011
Start with a good block diagram, make an assessment of what you really need based on the type of flying you do. Do you really need 4 com radios? From the block diagram you will be able to figure out the interfaces to achieve the functionality you desire. Once that is clear and you assure you have the necessary com ports available it becomes easier to figure out each interconnect. Get a copy of The Aero Electric Connection for some theory behind wiring in general. The install manuals for each of the other items will be necessary to get the wiring correct, ports set-up and everything playing nice together. If you are new to this find someone that can help evaluate your plan and give you wiring tips based on your experience and ability. Best to get the kinks out of the plan before the first wire is placed.
Wiring a complex panel is fun and can be done without error if you plan well and study the options. Be sure to document your plan and the as-built condition for future reference. Label your wiring.
Good luck.


Murray M.
Dec 26, 2009
Saskatoon SK CAN
Good planning will keep the problems upgrading to a minimum. Asking questions is a good start.

Depends on your mission and your risk tolerance. I'm VFR only. I have electronic ignition and fuel injection so electrical power is important but I kept it simple. Single battery and single alternator. The battery is for starting. After that the alternator supplies all the power so two batteries seemed like overkill for me.

I do have a simple failsafe system should the normal electrical bus fail for what ever reason. I used relays to switch the essential equipment to battery power to keep me flying for a short time. NC is connected to the regular electrical system. This is opposite to just about everything published about electronic systems that keep aircraft engines running. Hey, it's experimental. Your risk tolerance may be different. If I were to change anything it would be to add a second alternator but I would keep the single electrical bus.

A couple of things not on my essential bus, Skyview, it has it's own battery, and the P-Mags. They have their own power source once running. My cell phone will get me in contact with ATC if the radio dies. I think that is why headsets have bluetooth. ;)