Wiring a Dual EFII system using Aeroelectric Z-13

[unitink72]

Originally Posted by rv6ejguy

One breaker for 2 ECUs gives you a single point of failure.

On my system (dual bus), since the two ECUs would be wired off of independent busses, they would each get their own breaker. The same goes for the coils and fuel pumps.

[219PB]

Originally Posted by majuro15

So Paul, I'm assuming you're running the Bus Manager as well?

Yes, I am installing the Bus Manager.

[JurcaSperocco]

I'm installing the EFII six cylinder ignition version and the wiring is as follow:

- Bus Manager's Essential, redundant with the included emergency power switch switch, plus an additional external bypass made of a 40A relay with 2 Schottky diodes wired on the 2 batteries.

Since this is a 6 cylinder engine, EI works with 3 coils and if you turn off the third Coil, you'll lose the cylinders 5 & 6. The only way to proceed to "mag selection" is to shut off one ECU at a time (they have a quick run up boot program).

- ECU 71: 5A breaker plus ON/OFF SPST switch for "mag 1" selection.

- ECU 88: 5A breaker plus ON/OFF SPST switch for "mag 2" selection.

Note: I've found 2 leds illuminated SPST switches: red when OFF, green when ON. Fancy! They are protected by 3 switch guards.

- 3 COILS: manual says all in one with a 15 A breaker. This is to me a single point of failure so I've added a protected SPDT switch going to a second 15A breaker in case the first fails.

- BTW, Bus Manager's Main is going to the VP-X Pro, with the same kind of double Schottky redundancy.

May be too cautious, but I think an "electric airplane" needs extra-care to be safe.

Hope this helps.

[Bluelabel]

Definitely can't hurt to add extra protection where you can... however, you should note that even though there are three coil packs, each coil is its own individual unit. Unless you looose the whole plug to a coil, you would never looose a whole coil.
When I shut down one ECU during my run up test, I have 1.5 coils running either the top or bottom plugs.

[JurcaSperocco]

You are right John.

Mine is a 6 cylinder and the purpose of my message is I definitely can't shut off the third Coil at all. This would make me lose the entire last 2 cylinders (the third Coil, even though it's a dual coil, is powering the top and the bottom of these cyl. 5 & 6).

That's why the "mag selection" is done, in that 6 cyl. case, shutting off the ECUs.

Happy building!

[Larry DeCamp]

It is my understanding of input from Ross ( SDS) that coils and CPU's shall be fuse protected independently. Therefore, it is my expectation that any type of coil or CPU failure, whether open or short, would be benign with respect to "upstream" busses and devices. So I plan to assure there are two paths of battery power to THE buss from which the EPI's get power. Any comments from this obviously knowledgeable group ?

[rv6ejguy]

Please be aware that SDS and EFII architectures are quite different, especially on the dual ECU 6 cylinder systems. I don't want people to be confused here.

[pitts flyer]

I find it interesting that no one has yet mentioned the power lead for the injectors (though perhaps I missed it). I just installed an Aerosport IO-375 engine on my airplane which came with the EFII dual ECU system. As I understand (and I could be mistaken) there is a single wire (red) which powers all of the injectors, and the ground leads from the injectors go to the ECU's which control their operation. The EFII system does not have independently controlled injectors, which is why you can use any of the leads for any of the injectors. (as an aside, I think this can be rewired by changing the ground leads from the injectors to the "Injector drive plug" on each of the ECUs and wire them to specific terminals on those plugs so that they can be tweaked individually--alla Dave Anders setup). That injector power lead was bundled with the ignition coil leads, which could be wired to switch buses through a switch (which then that switch becomes the single point of failure, along with the wire to the injectors--I believe that if you lose power to that injector power wire, your engine stops). I choose to separate the ignition coil power leads and wire them to their respective ECU power sources (also each pump is run from the separate power sources). Then I used a SPDT switch to select the power source for the injectors. As recommended in other posts, I have a separate battery and power bus as a backup, which is totally independent (other than a power diode for charging the battery) from the main bus battery and alternator.

I don't know if it is right or wrong, but I believe it gives me a little more redundancy and backup alternatives. Though the switch and power lead to the injectors is still a single point of potential failure--there is no getting around that practically.

[Toobuilder]

The individual cylinder trim function is a software enabled feature. Its my understanding that despite the fact that the EFII product is based on the SDS CPU, Robert does not offer that (and a variety of other functions) for the EFII product. Somebody feel free to set me straight if this is inacurate.

[fly3g]

Dave M - I wondered what to do with the single injector lead too. My plan was similar to yours except to wire through a DPDT switch instead of a SPDT. Wired in parallel thru the switch to have two sets of contacts in the mechanism controlling the current. Not sure what the switch failure modes really are mechanically for the DPDT switch so I don't know if this really increases reliability/redundancy of the switch path. Of course you would never know if both legs were always working unless you occasionally inspected the switch. Two independent SPST was the other option but I don't want another switch....