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Circuit breaker for EFIS?

Tram

Well Known Member
Anyone here not running the VPX setup?

We are contemplating a Skyview upgrade in our 6 and looking at options.

Planning a fairly basic system, we mostly fly VFR, but would like IFR capabilities for getting through layers, etc.

Those of you not running the VPX system, what is your answer?
 
Is 'yes' too simple for an answer?
I run 3 EFIS displays, each on its own pullable breaker. One with automatic switchover to a backup battery.
 
Anyone here not running the VPX setup?

We are contemplating a Skyview upgrade in our 6 and looking at options.

Planning a fairly basic system, we mostly fly VFR, but would like IFR capabilities for getting through layers, etc.

Those of you not running the VPX system, what is your answer?

Three RVs will full SkyView installs and no VPX (and never will have one).

The SkyView power requirements and recommended breaker sizes are well documented in their detailed install manual. Very simple.

Carl
 
Three RVs will full SkyView installs and no VPX (and never will have one).

The SkyView power requirements and recommended breaker sizes are well documented in their detailed install manual. Very simple.

Carl

Kinda what I was thinking. Just didn't want to be alone. LOL
 
Four flying experimentals in our household - all with CB's for the EFIS's. Makes it easy to power cycle them when doing software maintenance. It just works for me.
 
Let's not forget the lowly fuse. Lighter, cheaper, equally reliable, and they power cycle with the same two fingers ;)
 
Dual SV 1000T on a 12 fuse block with a few breakers for control of things I want to see and manage without pulling a screen or ducking under panel. Plus, I was out of fuse slots and didn't want to double up on any.

If only running fuses, you'll likely need more than 12.
 
I think the question may not be fuse or breaker but "ability to turn off the efis while flying"

I installed my EFISeseseses (IFii?) with fuses. I chose to turn them on with an avionics master or a staged battery bus backup switch. The GRTs do not have a built in power switch. This means that in order to power down my Primary Flight Display, all my panel has to go completely down.

In experiential retrospect it is obvious that I should have installed a pilot accessible way to reboot the screens and maybe even reboot the AHARs without loosing the NAV and COM equipment.

So, my recommendation is to NOT do what I did.

If you choose fuses, put in power switches. Or put pullable breakers on the panel. My preference on a do-over would be pullable breakers for these and fuses everywhere else.
 
I was planning pullable breakers, but many of the people I've spoken with seem to speak of the VPX like it's mandatory, and I didn't feel like it was.
 
I was planning pullable breakers, but many of the people I've spoken with seem to speak of the VPX like it's mandatory, and I didn't feel like it was.

They are giving their opinion. Airplanes have been flying for a very long time. With fuses and breakers - that's a fact.
 
A 5Amp Kloxon 7277 from Spruce will take care of the screen. There will be two red wires twisted together out of the harness that go to the breaker (or fuse). I prefer breakers to fuses because they pop, and are usually in the panel. A fuse in the panel with a light that comes on when it blows would be fine, but hidden fuses can be a nightmare in my experience, especially for the next guy to own the plane, because he lost the wiring paperwork given to him when he bought it.

Give me a call and I can talk you through the process.
 
I was planning pullable breakers, but many of the people I've spoken with seem to speak of the VPX like it's mandatory, and I didn't feel like it was.

Really find it difficult to understand why anyone would want a VPX! Triumph of marketing over logic... My panel (2 x EFIS) uses fuses.

Pete
 
I just don't trust the VPX - solid state switches run by logic chips have too many "gotchas" involved for me. I ran switches and pullable breakers for everything, and I'm quite happy with it. Dual Skyview with 430W and Garmin G5 backup.
 
The fuse vs CB argument is about like politics (or even [shudder] primer), but this thread did bring up something I wouldn't have thought needed bringing up.

Which of the current crop (within the last 10 years) of EFIS offerings needs to be rebooted in flight, or even after engine start? Which do, and don't, have their own power switches in the unit?

I never reboot any of my current gauges, so it never occurred to me that an IFR-capable EFIS might need that capability.....

Charlie
 
The fuse vs CB argument is about like politics (or even [shudder] primer), but this thread did bring up something I wouldn't have thought needed bringing up.

Which of the current crop (within the last 10 years) of EFIS offerings needs to be rebooted in flight, or even after engine start? Which do, and don't, have their own power switches in the unit?

I never reboot any of my current gauges, so it never occurred to me that an IFR-capable EFIS might need that capability.....

Charlie

I have never re-booted in flight. (GRT/Dynon D6). Such a thing would be highly unusual. The arguement for no power switch on the unit is that you are more likely to accidentally turn it off, than to need it. I have no idea if this is correct or not. I have mine on pullable breakers. I believe no EFIS should be on and connected to the main buss during engine start. Low voltage, not high, is the enemy of modern electronics. Choices are to boot up and run on an aux buss before and during engine start, or delay boot up until after.
 
Thanks, Bob; that's encouraging. And to return the favor, you can put your concerns about undervoltage to rest, excepting, of course, voltage going so low the device cannot operate (which isn't actual damage; just potentially damaging to safe flight).

Risk of actual damage to *electronics* from undervoltage went away about the time mfgrs quit using germanium semiconductors and moved to silicon (about 50 years ago). Any actual damage from voltage changes will be either full-on overvoltage, or 'spikes' of overvoltage that can occur for various reasons. And if the mfgr has done their job correctly, even fairly massive spikes on the power supply lines can be handled without damage. The FAA has docs that define how much, and hopefully, any exp. EFIS mfgr would use those docs as guidelines for any product they hype as capable of IFR work. It would be nice to know of any that don't.

Charlie
 
Give me a call and I can talk you through the process.

That's very gracious of you. I'll pick your brain when we get closer. Thanks.

Really find it difficult to understand why anyone would want a VPX! Triumph of marketing over logic... My panel (2 x EFIS) uses fuses.

Pete

Well, for me was the initial cost. $1,500 for something that a $20 breaker is capable of? Obviously, it's not that cut and dried, but still, I don't think I'd need any of the added benefits of the VPX.
 
I have never re-booted in flight. (GRT/Dynon D6). Such a thing would be highly unusual. The arguement for no power switch on the unit is that you are more likely to accidentally turn it off, than to need it. I have no idea if this is correct or not. I have mine on pullable breakers. I believe no EFIS should be on and connected to the main buss during engine start. Low voltage, not high, is the enemy of modern electronics. Choices are to boot up and run on an aux buss before and during engine start, or delay boot up until after.

As someone else pointed out, low voltage during start is not a problem for modern avionics. If the EFIS has a backup battery, then even that problem is solved (e.g., Dynon Skyview). Plus, with no EFIS, it's likely you don't have engine monitoring available with many of these systems.

I always start with all the avionics on (in fact, I don't even have an avionics master switch - i.e., SPF - on my plane) and have had no issues. If something does drop off-line (e.g., 430W), then so be it...it restarts immediately when power rises to above the operating threshold.
 
The fuse vs CB argument is about like politics (or even [shudder] primer), but this thread did bring up something I wouldn't have thought needed bringing up.

Which of the current crop (within the last 10 years) of EFIS offerings needs to be rebooted in flight, or even after engine start? Which do, and don't, have their own power switches in the unit?

I never reboot any of my current gauges, so it never occurred to me that an IFR-capable EFIS might need that capability.....

Charlie
Hi Charlie,
Like Bob, I have never had a need to reboot my EIFS (GRT) in the air but what I find CB useful is when I am in the hanger and working on some avionics. All of my avionics run thru their own CB and I can simply pull the power on those that I don't need to be running. Of course some of them like Garmin has the knob that you can turn it off but my other avionics (EIS, EIFS, fan, etc) don't have an on-off switch and by pulling the CB, I can conserve my battery and only work on the unit that I needed it on. Watching recorded flight is an example of such need which I can leave only one EIFS on and the rest turned off.

In regards to VPX, like many others, I simply don't like the idea of running all or much of my electronics thru one system/unit which creates a single point of failure. VPX is a form of a computer and computers have bugs.
 
As someone else pointed out, low voltage during start is not a problem for modern avionics. If the EFIS has a backup battery, then even that problem is solved (e.g., Dynon Skyview). Plus, with no EFIS, it's likely you don't have engine monitoring available with many of these systems.

I always start with all the avionics on (in fact, I don't even have an avionics master switch - i.e., SPF - on my plane) and have had no issues. If something does drop off-line (e.g., 430W), then so be it...it restarts immediately when power rises to above the operating threshold.

I had heard some older avionics are not as tolerant towards lower voltage and could get damaged. When I was building, I checked and confirmed this by some avionics shop but don't remember the details or brand at this time. My EIS which was confirmed to be very tolerant towards low voltage comes on with the master and I will have info on engine vitals (oil pressure) during the start up, after that my avionics master switch will turn all the avionics.
 
I considered VPX and breakers for my night VFR 7A with SkyView before settling on automotive blade fuses for simplicity, reliability, and cost. I didn't switch the Skyview because I leave it on during engine start, and never plan to turn it off in flight. I could turn the Skyview off by holding down the left button if I the need arises. I did install a power switch for autopilot servos in case the disconnect circuit fails.

I am still happy with my choice, and still considering a VPX for my next build. Features I like include password security, variable flap and trim controllers, and wig wag. I still like blade fuses for simplicity and reliability. I have never had a fuse fail because I size them to protect the wire, not the device they power.

Thanks to VPX for making their load planning spreadsheet available to anyone, I used it to help plan my fuse system.

Jay
 
Plus, with no EFIS, it's likely you don't have engine monitoring available with many of these systems.

I leave my GRT EIS on during engine start; it (and a big red light) show immediately if there's no oil pressure, low buss voltage, etc.
 
Pullable

I went with circuit breakers for my build over the VPX and it was a non event. If I were to change anything, I would replace the standard circuit breakers with "pullable" circuit breakers. I have a couple but should have done all of them that way.
Good luck on your build!
 
I had heard some older avionics are not as tolerant towards lower voltage and could get damaged. When I was building, I checked and confirmed this by some avionics shop but don't remember the details or brand at this time. My EIS which was confirmed to be very tolerant towards low voltage comes on with the master and I will have info on engine vitals (oil pressure) during the start up, after that my avionics master switch will turn all the avionics.

Same setup for me and and for the same reason.

The only thing on my master is the Skyview and EICommander.

All the other electronics are are on an Avionics Master and then each devise is protected by an individual pullable breaker.
 
seems like with a Dynon with battery, one would need to use the reboot/shutdown button on the display anyway, so a CB wouldn't make a difference here over a fuse?
 
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