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ronburnett(at)charter.net
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 Posted: Wed Nov 10, 2021 5:56 am Post subject: ORe: Re: RV-10 Electrical Review with Electric AC and FlyEFI |
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Here is the bottom line,in this Marine’s opinion, having flown dual EFII and now system 32 since 2017. If anything goes wrong, it is wise to land, rent a car, call a friend, or whatever. Do you want yourself, let alone possibly 3 others in jeopardy over your clever planning.
Initially I flew myRV-6A Subaru conversion with Ross Farnum’s system and then after a piston failure and immediate return to my airport it took me 4 years to get an O360 Lycoming with dual EFII flying. For a few months I have been flying with the system 32. Have always had the Bus Manager. Now I have 270 hours on the Lycoming, and dual Oddessey PC-680 batteries on the firewall. I buy one new battery each year but if the alternator quits, personally I wouldn’t fly more than 20-30 minutes max.
Good luck, but remember there is always a weak link somewhere.
Ron Burnett
May you have the Lord's blessings today!
Sent from my iPad
| Quote: | On Nov 9, 2021, at 9:52 PM, Sebastien S <cluros(at)gmail.com> wrote:
Hello Michael,
I’m currently debugging a FLYEFII install on a Murphy Rebel. The fuel pumps are definitely a conundrum. Fuel pump dependant aircraft are nothing new and for a century the solution has been to run both the primary and the backup pump during critical phases of flight. This doesn’t seem to work well with the FLYEFII system so they have that relay to enable only one pump at a time. If you install their “Bus Manager” it includes a circuit to keep an eye on the fuel pressure and switch to the backup pump if necessary. Without this system I see only two options:
1. Create your own monitoring and automatic switching system,
2. Run both pumps during critical phases of flight. This will require careful testing since it might cause problems in an effort to avoid a potentially catastrophic one.
As for your second battery, I would suggest putting it in the front. You’ll need to be careful not to overheat it and you’ll end up carrying ballast in the baggage compartment when light, but when heavy you’ll have more useful load.
> On Nov 9, 2021, at 18:49, melstien <michael(at)elstien.us> wrote:
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> Hello John,
>
> Yes, I like to keep track of my changes so I try to add revision tags. I don't always remember.
>
> I will take a look at the failure modes and probably better align this to the Z101 and also try to organize it so it makes physical sense. That will also allow me to see where all my connection points should be. Currently it is just electrically correct (or will be if people suggest good changes)
>
> I will add separate filed switches on the alternators. I was not sure and that was one of my questions.
>
> The 40 Amp AC will be an experiment. I do not plan to add it to the alternator load except during level flight at altitude and near an airport. AC is a luxury. The Earthex batteries can draw at least 100 amps continuously so I think they will pick up any sag and my IBBS batteries on critical avionics are also meant to do that as well.
>
> Engine Bus answers:
> 6 Cylinder as opposed to a 4 cylinder
> Yes, everything will have its own power lead and the coil packs will have a fusable link and a breaker
> Injectors will have a fusible link only
> I planned to not have the pump on automatice failover but to run them both during takeoff, landing and fuel tank switch-overs but Robert at FLYEFII did not suggest that. he thought it might cause cavitation on the inlet. My testing using my actual fuel lines and pressure regulator indicated that running both at the same time more than doubled the current draw (4.9 amps per pump solo) and the fule flow increased marginally. I think they were both fighting each other to supply pressure at the pump outlet and it was still only going through qty 1 -3/8 inch hose.
> I had thought about splicing each injector wire and coil pack power feed into 2 wires and feeding them off Engine Bus A and engine Bus B all with diode isolation. The schematic looked cool but it introduced to many connections points which would probably have increased failures.
>
> FLYEFII suggests a 10 Amp fuse for the for the pumps and my load testing indicates they only use 4.9 when run separately. I can review the wires size I used and see if it will support a 12 or 15 amp breaker.
>
> FlyEFII did not state what the coil pack would need when powered separately. They have the coil packs and the injectors all being fed by 1 15 amp fuse. I suspect that the coil packs will still need a 15 amp fuse per coil pack because they all charge at different times, so splitting them into 3 does not reduce the peak current, just the frequency it occurs. (I am a Mech Engineer so I am looking for guidance on that.) I have reached out to FLY EFII and requested guidance.
>
> FlyEFII informed me that the system at high RPM will consume 11 AMPs. That is all I have to go on. to meet my 1 hour of reserve, I can always move up the ETX 1200 battery. Its the same form factor and will carry an 18 amp load for 80 minutes. If that is not enough there is always the ETX1600 (120Amp/hours). Even two of the 1200's weight less than 1 PC680. Money is just the issue. Not a place to skimp.
>
> Regarding the coil packs, cylinder 1-4 are spread across coil packs A and B so they are redundant. If you lose A or B you still have 1 working plug per cylinder 1-4. FLY EFII added the 3rd coil pack and both plugs for cylinders 5 and 6 are on the same pack. I have informed FLYEFII that I would suggest a different arrangement so both plugs were not on the same coil pack. I do know of a person who lost coil pack C and the engine ran without too much vibration, but I need to check into that story.
>
> I have 2 LR3Ds and the higher output backup alternator. I just noticed they come with an amber light. I will ties these outputs into my EFIS but a good light is also nice. I Prefer LED for lower heat and better vibration and longer life.
>
> OV Sense, so this is the contact that senses the buss voltage and is used to increase or decrease the voltage ouput? I have them both going to the Main Bus, but maybe the backup should go to the engine bus. There is a possibility the main bus has power but the engine bus does not. Your thoughts?
>
> I reviewed your diagram and it is really what I intended mine to be, only with the second battery.
>
> Thanks for the feedback. I appreciate it.
>
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> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=504060#504060
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melstien
Joined: 02 Feb 2013
Posts: 4
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| Posted: Thu Nov 11, 2021 5:24 pm Post subject: Re: ORe: Re: RV-10 Electrical Review with Electric AC and Fl |
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Hello Ron,
I agree with your comments and thoughts.
My goal upon any failure: Alternator or battery or... is the same as it would be without EFII, which is to land as quickly as possible, not to continue the flight. I am trying to minimize how one failure causes the engine to get quiet.
My goal of 1 hour of battery life is to enable proper time to get down from altitude in a location (think Central US or upstate NY) and in IFR conditions where landing may not be a simple task. If in VFR down here in Florida, we could be talking 5-10 minutes to the nearest airport.
It sounds like you like you like the System 32.
Thank you for your comments.
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