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PC680 vs PC925
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philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Tue Feb 24, 2015 7:38 pm Post subject: PC680 vs PC925

I look forward to seeing how it behaves.  My G3X is backed up my a backup battery and my Dynon D6 has and integrated backup battery as well.   I just don't see any possible way for them to blink.  If they do, and can just keep the contactor or open during the start.  My G3X is wired to both busses so buss 2 would keep it running. 



It will be interesting to see.   The first engine start isn't too far away.  Should be this spring or summer. 



Phil



Sent from my iPad



 	  Quote: 	
		   On Feb 24, 2015, at 9:19 PM, nukeflyboy <flymoore(at)charter.net> wrote:

 

 

 

 While the battery still has amp-hours remaining during cranking, the voltage drops low enough that the EFIS will crash.  On engine start you will want to see your engine monitor so reboots are a PITA.  You will also have to restart your checklist, or re-enter anything else you have done (navigation, for example).  I am sure it causes no harm to the EFIS (mine a G3X), but it does take 30 seconds or so to recover.  For this reason you do not want to cross tie your batteries on start unless you have just about killed your starting battery.  

 

 Needless to say, your EFIS needs to be on a different battery than the starting battery.

 

 --------

 Dave Moore

 RV-6 flying

 RV-10 QB - flying

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438689#438689

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Tue Feb 24, 2015 7:49 pm Post subject: PC680 vs PC925

The TCW solutions are very helpful.  I have the Battery Backup behind the G3X. If I deal with reboots, which I don't think will happen, the IPS would be a very elegant and fairly simple solution to add. 

There's some innovative stuff in their portfolio for real problems. 

Sent from my iPad

 	  Quote: 	
		   On Feb 24, 2015, at 9:25 PM, Bill Watson <Mauledriver(at)nc.rr.com> wrote:

> On 2/24/2015 8:06 PM, nukeflyboy wrote:

> 

> 

> You didn't mention if starting with the X-feed closed (both batteries) causes the EFIS to shut down.  This is the main reason I keep the 2 Z-14 busses separated on startup.  Like your experience, a start on one 680 does not impress you, but usually works.  For this reason I am contemplating replacing one with a 925.

 I have (3) GRT HX EFISs that come on with the master.  They do not have a discrete switch or switches.  Pre-start flight plan entry requires the G430 to be powered on as well.  Initially, if I took more than 5 minutes to setup my flight plan and call clearance delivery on a cold day, when I did a linked start it was likely that my (3) EFISs would re-boot.

 It became obvious that having all (3) screens come up involved more of a load than I anticipated.  An obvious solution would be adding individual switches which would allow only 1 to be brought online until after the start.  But I've become accustomed to the EFISs being in 'always on' mode and I like the fact that they cannot be switched off inadvertently.

 What I did was add TCW's IPS (Intelligent Power Stabilizer) and connected it to the EFISs and the G430.  This solved the problem.  I now do all starts with both batteries linked with no reboots.

> I have also had marginal reliability with the Odessey batteries lately, having to replace them more frequently than expected.

 I've had some problems with battery life.  One problem was clearly tied to the need for 'clock power' on the (3) EFISs.  This tended to run the battery down if not flown regularly.  When GRT started picking up the time from the GPS, disconnecting the clock power lines clearly had a positive effect on battery life.

 In my case, I think cold starting my IO-540 with the light wt starter on one 680 may be considered a bit abusive.  That is, it may reduce its life.  Nuckolls suggested as much and my experience so far is consistent with that.  Using both batteries on all starts, I seem to be getting the performance and life I expect out of the 680s but I don't the data to confirm that yet.

 I've had to make some changes to get things to work the way I've wanted but at this point I'm very satisfied with 2 680s.  Replacing one with a 925 seems like overkill to me.

Mauledriver(at)nc.rr.com
Guest

Posted: Tue Feb 24, 2015 7:51 pm Post subject: PC680 vs PC925

On 2/24/2015 7:33 PM, Phillip Perry       wrote:

     

      	  Quote: 	
		                Bill brings up a point worth a bit of discussion.   In the         Z14 model, I can't really see any situation where I would throw         my cross-feed contractor in flight.  I would always use it at         start and then shut it off and likely never touch it under any         circumstance.  

       

       

     	
     You are forgetting about the obvious one - a failed alternator.      That's where the Z14 shines because it turns a battery endurance     situation into a 'hit the switch and carry on'. But you know that.

      	  Quote: 	
		         The theory is that if a component on one of the busses shorts         I t should trip a circuit breaker, but the buss should stay up         and running.  However if the buss itself shorts and goes down,         the last thing I want to do is throw the cross-feed and short         the unaffected buss too.  If that occurred I'd be flying blind         while I figured out what happened and once I figured it out I'd         be dealing with the time required for reboots to complete and         possible calibration issues of rebooting inflight while in an         unusual attitude (remember I'm flying blind).

     	
     I didn't consider a bus short a likely failure scenario... at least     no more likely than shorting a unprotected fat cable.  The     installation of the wires and cables that make up my two buses is     robust and durable enough for that not to be a likely type of     failure.  OTOH, any component may go belly up for a variety of     reasons but they are all protected with fuses or a breaker.  And I     agree, there is no reason for bus linking in the case of a component     failure or short.  I've gone almost 100% fuses so a shorted     component wouldn't normally even be reset.

     

     Generally speaking just as you suggested, there's no reason to ever     link the buses in flight unless there is some indication of a     charging problem (e.g. alternator failure).

      	  Quote: 	
		         

       

       The secret is to pay close attention to what equipment goes         on which buss so you can handle a buss failure gracefully. Some         of my equipment has dual 12v inputs and that equipment has one         input from buss 1 and the other from buss 2.  Other equipment         with a single 12v input (that could be deemed critical or really         convenient to have) can be connected to each buss through a pair         of diodes pointing in opposite directions. This will allow the         electrons to flow off one of the busses and into the equipment         without cross-feeding onto the other buss. 

       

     	
     I took a slightly different approach with my GRT EFISs; they can     have up to (3) 12v inputs and will automatically get power from the     input producing the most.  However, I've only hooked them up to one     bus (all 3 inputs are linked to one bus for some physical redundancy     and with no power on/off switch in the circuit to eliminate a point     of failure).  The reason I keep them on one bus is so I can control     what battery is drawn down when they are powered on before engine     start.  I could add switches  but that would add complexity and     multiple additional points of failure.

     

     So I depend on the dual buses and the ability to link them as the     way to provide redundant power to the EFISs.

      	  Quote: 	
		         

       

       With some planning you can really build a very redundant         electrical system and panel with very very little added         complexity. 

       

     	
     Agreed but it continues to be a learning experience for me.

     

      [quote][b]

Lenny Iszak

Joined: 23 Mar 2008
Posts: 270

Posted: Tue Feb 24, 2015 10:12 pm Post subject: Re: PC680 vs PC925

I have a 925 in the back and I never have to worry about not having enough juice for starting.



Less worry about additional contactors (and their power consumption) and other complexities too. The capacity is pretty similar to two 680s in case the alternator quits.



For backup I have two 6V 12A batteries in series, under one of the flap torque tube covers. Stole that idea from Tim Olson. Tim has 4 of them though. 

I charge them with a marine charge controller: https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A



Lenny

_________________
Lenny Iszak
Palm City, FL
2014 RV-10, N311LZ - 500 hrs

glastar(at)gmx.net
Guest

Posted: Wed Feb 25, 2015 12:07 am Post subject: PC680 vs PC925

Wonder why most of the people are so heavily looking at the engine 

monitor being up on start?

On my Glastar I have in // to the EMS a pressure switch which comes 

alive I think with 25 or 30 psi, that linked

to a LED shows me immediately on start up if the oil pressure comes up 

and it is a very cheap (and the only)

backup for my EMS.



And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.



Cheers Werner



On 25.02.2015 04:19, nukeflyboy wrote:

 	  Quote: 	
		   ...  On engine start you will want to see your engine monitor so reboots are a PITA.

bill.peyton

Joined: 19 Sep 2010
Posts: 198
Location: St. Louis, MO

Posted: Wed Feb 25, 2015 6:10 am Post subject: Re: PC680 vs PC925

I have a dual bus system with two alternators, a PC680 and PC925L.  I manage the batteries using an automated charge relay.  This device is manufactured by Blue Seas Technology. P/N 7611.  The ACR monitors the charge voltage, battery voltage and charge current and will automatically connect or disconnect depending on the parameters.  This system will never allow a dead battery, or shorted battery to be combine charged, which is extremely important with a dual battery system.  This system will not combine the batteries for starting, and will only combine the batteries when the charging bus is greater than 13.5 volts.  Either alternator and either side of the bus can be used to charge both batteries.  I typically fly with only the main alternator field energized and treat the second alternator as a standby.

The dual bus allows me plenty of time to get a clearance and enter flight plans, then start the engine on the 925 without any ill affect to the avionics.  The 925 has plenty of juice to rapidly spin up the engine for starting.  I have no experience with just the 680.

_________________
Bill
WA0SYV
Aviation Partners, LLC

carl.froehlich(at)verizon
Guest

Posted: Wed Feb 25, 2015 6:27 am Post subject: PC680 vs PC925

Yep - that is what I do.  The panel comes up after engine start.  While

Dynon assured me the SkyView system is not at risk for engine start voltage

transients, Garmin provided no such guarantee.  The last damn thing I want

is to have to engage Garmin again to fix the GTN-650.  In any case, why

expose these high price electronics to such transients if not needed?



Carl



--

flying-nut(at)cfl.rr.com
Guest

Posted: Wed Feb 25, 2015 7:01 am Post subject: PC680 vs PC925

You have a point, but the starting transient problem pretty much goes 

away when you add the reverse current diode across the master and start 

contactor coils.

Also, modern electronics (should) have switching power supplies which 

are fairly immune to those reverse-current spikes.

I put dual MGL Odyssey panels in my RV-10 (not flying yet) panel and 

each one has it's own backup battery ...... a sealed battery for that 

goes into exit lights.



There isn't that much current draw for the panels themselves.



Having said all that, I wouldn't want to risk a Garmin repair cost either!!

Linn ..... mounting wheel pants



On 2/25/2015 9:24 AM, Carl Froehlich wrote:

[quote] 



 Yep - that is what I do.  The panel comes up after engine start.  While

 Dynon assured me the SkyView system is not at risk for engine start voltage

 transients, Garmin provided no such guarantee.  The last damn thing I want

 is to have to engage Garmin again to fix the GTN-650.  In any case, why

 expose these high price electronics to such transients if not needed?



 Carl



 --

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Wed Feb 25, 2015 7:03 am Post subject: PC680 vs PC925

Well, I took what I perceive as a simpler route. One PC925L battery, a 

Dynon backup battery on each screen, and a separate switch for my GTN650 

and my second Dynon screen. Mostly to minimize electrical load before 

start to a single screen. If I wanted the 650 to be on and stay on 

during start, I would put a TCW IBBS on it. I don't perceive much 

benefit from doing dual bus, dual battery, dual alternator systems as I 

don't intend to fly that much IFR. Not to mention my IFR flying started 

35 yrs ago with two venturis to drive AN AH and DG, with single nav/com 

and single manually tuned ADF. No transponder, just bare bones. Not sure 

I will be able to handle no ADF, full Dynon Skyview EFIS with GTN650 and 

knowing exactly where I am on any chart. 8^)



On 2/25/2015 7:24 AM, Carl Froehlich wrote:

[quote] 



 Yep - that is what I do.  The panel comes up after engine start.  While

 Dynon assured me the SkyView system is not at risk for engine start voltage

 transients, Garmin provided no such guarantee.  The last damn thing I want

 is to have to engage Garmin again to fix the GTN-650.  In any case, why

 expose these high price electronics to such transients if not needed?



 Carl



 --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Wed Feb 25, 2015 7:16 am Post subject: PC680 vs PC925

The problem during start is NOT transient spikes, especially of higher 

voltage. The problem is LOW voltage from the starter current draw.

Most avionics today are rated for 8 - 32v because they have their own 

power supply controlling voltage to what the individual circuit boards need.

1960s avionics had first generation transistors and ICs that were very 

sensitive to low voltage and were easily fried by same. But the industry 

ASSUMED that there were high voltage spikes, so implemented avionics 

master switches. It solved the problem, without ever determining what 

the real failure mode was.

On 2/25/2015 7:57 AM, Linn Walters wrote:

[quote] 

 You have a point, but the starting transient problem pretty much goes 

 away when you add the reverse current diode across the master and 

 start contactor coils.

 Also, modern electronics (should) have switching power supplies which 

 are fairly immune to those reverse-current spikes.

 I put dual MGL Odyssey panels in my RV-10 (not flying yet) panel and 

 each one has it's own backup battery ...... a sealed battery for that 

 goes into exit lights.

 There isn't that much current draw for the panels themselves.

 Having said all that, I wouldn't want to risk a Garmin repair cost 

 either!!

 Linn ..... mounting wheel pants

 On 2/25/2015 9:24 AM, Carl Froehlich wrote:

> 

> <carl.froehlich(at)verizon.net>

>

> Yep - that is what I do.  The panel comes up after engine start.  While

> Dynon assured me the SkyView system is not at risk for engine start 

> voltage

> transients, Garmin provided no such guarantee.  The last damn thing I 

> want

> is to have to engage Garmin again to fix the GTN-650.  In any case, why

> expose these high price electronics to such transients if not needed?

>

> Carl

>

> --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

flysrv10(at)gmail.com
Guest

Posted: Wed Feb 25, 2015 9:03 am Post subject: PC680 vs PC925

I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?  

I also wonder why everyone is making their system so complicated. 

Don't mean to criticize.  I am thinking that others have had experienced that I have not had and perhaps all the efforts are based on past events. 

Thanks. 

Do not archive. 

Sent from my iPhone

 	  Quote: 	
		   On Feb 25, 2015, at 3:03 AM, Werner Schneider <glastar(at)gmx.net> wrote:

 Wonder why most of the people are so heavily looking at the engine monitor being up on start?

 On my Glastar I have in // to the EMS a pressure switch which comes alive I think with 25 or 30 psi, that linked

 to a LED shows me immediately on start up if the oil pressure comes up and it is a very cheap (and the only)

 backup for my EMS.

 And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.

 Cheers Werner

> On 25.02.2015 04:19, nukeflyboy wrote:

> ...  On engine start you will want to see your engine monitor so reboots are a PITA.

rv10flyer(at)live.com
Guest

Posted: Wed Feb 25, 2015 9:28 am Post subject: PC680 vs PC925

IIm a control freak! I am constantly looking at the EMS. I also make 

mistakes, if I waited 10 seconds to find out that the CHT was sky rocketing 

for a reason I don’t know about until my EMS came on, well I would ask 

myself why I didn’t have more control of my engine, and feel I made a grave 

mistake. Oil pressure may not be an issue but stuck something in my engine 

may be. Engine starts, to me are the most critical time to assure there is 

nothing that is wrong with the engine. For me, having visibility to the 

engin, even if nothing ever goes wrong, it very reassuring.. Like I said Im 

a control freak when it comes to the engine. That and my wife's random 

question of "is that normal?" and the fear she'll ask me right after I start 

the engine and Im glad I can tell her based on facts.

--

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Wed Feb 25, 2015 9:30 am Post subject: PC680 vs PC925

Operating a dual dual system is really easy. There's very little that needs to be learned beyond throwing a switch.   It's good to know the system, but it's really not a burden.   The complexity is really a matter of understanding the wiring.  That's the part that most people get intimidated by. 

As far as EIS, we've always had oil pressure monitoring from the second he engine started it was just performed via an analog gauge.   I have seen Lycoming's that failed to produce oil pressure (or enough pressure to get in the green) after engine start.  That's why the gauge is there and every engine manual and pre-flight checklist says to start the engine, set the RPM, and confirm oil pressure in the green.   Without an operating EIS, you don't have RPM or pressure information. 

Also, I can personally attest to the value of seeing voltage information in addition to oil/engine information.  I melted down a C-152'a panel and caused a small fire when I was doing my flight training.  The starter bendix never disengaged from the flywheel and when I added power to adjust the RPM, the starter became an unregulated generator.   It dumped unregulated high voltages back into the electrical system smoking some equipment, lots of wires, and causing fire damage behind the panel.  It was a terrible experience. 

If I had voltage information from the start, I would have been alerted that there was higher than normal voltage on the buss and I would have known to shut it down and investigate more.

So there is value in having that information available.  In that cassette would have saved the FBO some $$ and kept their plane in service.   For me, it was just a lesson learned to check those voltages (with the alt off) while checking oil pressures after engine start. 

Phil

Sent from my iPhone

 	  Quote: 	
		   On Feb 25, 2015, at 10:51 AM, Flysrv10 <flysrv10(at)gmail.com> wrote:

 I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?  

 I also wonder why everyone is making their system so complicated. 

 Don't mean to criticize.  I am thinking that others have had experienced that I have not had and perhaps all the efforts are based on past events. 

 Thanks. 

 Do not archive. 

 Sent from my iPhone

> On Feb 25, 2015, at 3:03 AM, Werner Schneider <glastar(at)gmx.net> wrote:

> 

> 

> 

> Wonder why most of the people are so heavily looking at the engine monitor being up on start?

> On my Glastar I have in // to the EMS a pressure switch which comes alive I think with 25 or 30 psi, that linked

> to a LED shows me immediately on start up if the oil pressure comes up and it is a very cheap (and the only)

> backup for my EMS.

> 

> And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.

> 

> Cheers Werner

> 

>> On 25.02.2015 04:19, nukeflyboy wrote:

>> ...  On engine start you will want to see your engine monitor so reboots are a PITA.

flysrv10(at)gmail.com
Guest

Posted: Wed Feb 25, 2015 10:15 am Post subject: PC680 vs PC925

Phil, I am assuming that the Cessna had the engine information available at start up and guessing that it still did not help you prevent the melt down. Yes, there are times that malfunction happens at the worst time but is it worth all the complexities to prevent a rare event. In my many yes and hrs of flying, I never witnessed one on my plane and others. 

Sent from my iPhone

 	  Quote: 	
		   On Feb 25, 2015, at 12:25 PM, Phillip Perry <philperry9(at)gmail.com> wrote:

 Operating a dual dual system is really easy. There's very little that needs to be learned beyond throwing a switch.   It's good to know the system, but it's really not a burden.   The complexity is really a matter of understanding the wiring.  That's the part that most people get intimidated by. 

 As far as EIS, we've always had oil pressure monitoring from the second he engine started it was just performed via an analog gauge.   I have seen Lycoming's that failed to produce oil pressure (or enough pressure to get in the green) after engine start.  That's why the gauge is there and every engine manual and pre-flight checklist says to start the engine, set the RPM, and confirm oil pressure in the green.   Without an operating EIS, you don't have RPM or pressure information. 

 Also, I can personally attest to the value of seeing voltage information in addition to oil/engine information.  I melted down a C-152'a panel and caused a small fire when I was doing my flight training.  The starter bendix never disengaged from the flywheel and when I added power to adjust the RPM, the starter became an unregulated generator.   It dumped unregulated high voltages back into the electrical system smoking some equipment, lots of wires, and causing fire damage behind the panel.  It was a terrible experience. 

 If I had voltage information from the start, I would have been alerted that there was higher than normal voltage on the buss and I would have known to shut it down and investigate more.

 So there is value in having that information available.  In that cassette would have saved the FBO some $$ and kept their plane in service.   For me, it was just a lesson learned to check those voltages (with the alt off) while checking oil pressures after engine start. 

 Phil

 Sent from my iPhone

> On Feb 25, 2015, at 10:51 AM, Flysrv10 <flysrv10(at)gmail.com> wrote:

> 

> 

> 

> I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?  

> 

> I also wonder why everyone is making their system so complicated. 

> 

> Don't mean to criticize.  I am thinking that others have had experienced that I have not had and perhaps all the efforts are based on past events. 

> 

> Thanks. 

> 

> Do not archive. 

> 

> Sent from my iPhone

> 

>> On Feb 25, 2015, at 3:03 AM, Werner Schneider <glastar(at)gmx.net> wrote:

>> 

>> 

>> 

>> Wonder why most of the people are so heavily looking at the engine monitor being up on start?

>> On my Glastar I have in // to the EMS a pressure switch which comes alive I think with 25 or 30 psi, that linked

>> to a LED shows me immediately on start up if the oil pressure comes up and it is a very cheap (and the only)

>> backup for my EMS.

>> 

>> And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.

>> 

>> Cheers Werner

>> 

>>> On 25.02.2015 04:19, nukeflyboy wrote:

>>> ...  On engine start you will want to see your engine monitor so reboots are a PITA.

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Feb 25, 2015 10:17 am Post subject: PC680 vs PC925

On 2/25/2015 1:12 AM, Lenny Iszak wrote:

 	  Quote: 	
		   



 I have a 925 in the back and I never have to worry about not having enough juice for starting.

..and I don't think a single 680 is enough for an IO540 and the RV10.  
	


The 925 seems like the right battery for a single battery installation.

flying-nut(at)cfl.rr.com
Guest

Posted: Wed Feb 25, 2015 10:32 am Post subject: PC680 vs PC925

Thanks Kelly ..... the transients part came from Carl's email.

IMHO if your starter is drawing the voltage down to where the panels 

reset, I think you have either a bad (or too small .... CCA) battery or 

too small wiring to the starter ..... or both. OK, severe cold might do 

it ..... what's the CCA of a PCXXX battery at -10????



Like I said, a small, sealed Gel Cell battery as a backup will fix those 

'brownouts'.

I also see starting problems stemming from the use of the airframe as a 

ground return for the battery.  I ran a #2 cable to the engine for a ground.

Linn ..... mounting wheel pants



On 2/25/2015 10:13 AM, Kelly McMullen wrote:

[quote] 



 The problem during start is NOT transient spikes, especially of higher 

 voltage. The problem is LOW voltage from the starter current draw.

 Most avionics today are rated for 8 - 32v because they have their own 

 power supply controlling voltage to what the individual circuit boards 

 need.

 1960s avionics had first generation transistors and ICs that were very 

 sensitive to low voltage and were easily fried by same. But the 

 industry ASSUMED that there were high voltage spikes, so implemented 

 avionics master switches. It solved the problem, without ever 

 determining what the real failure mode was.



 On 2/25/2015 7:57 AM, Linn Walters wrote:

> 

>

> You have a point, but the starting transient problem pretty much goes 

> away when you add the reverse current diode across the master and 

> start contactor coils.

> Also, modern electronics (should) have switching power supplies which 

> are fairly immune to those reverse-current spikes.

> I put dual MGL Odyssey panels in my RV-10 (not flying yet) panel and 

> each one has it's own backup battery ...... a sealed battery for that 

> goes into exit lights.

>

> There isn't that much current draw for the panels themselves.

>

> Having said all that, I wouldn't want to risk a Garmin repair cost 

> either!!

> Linn ..... mounting wheel pants

>

> On 2/25/2015 9:24 AM, Carl Froehlich wrote:

>> 

>> <carl.froehlich(at)verizon.net>

>>

>> Yep - that is what I do.  The panel comes up after engine start.  While

>> Dynon assured me the SkyView system is not at risk for engine start 

>> voltage

>> transients, Garmin provided no such guarantee.  The last damn thing 

>> I want

>> is to have to engage Garmin again to fix the GTN-650.  In any case, why

>> expose these high price electronics to such transients if not needed?

>>

>> Carl

>>

>> --

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Wed Feb 25, 2015 10:36 am Post subject: PC680 vs PC925

It did and I didn't look to confirm it.  That's why I said an EIS would have prevented it because it would have flagged and over voltage annunciation and chimed my headset.  It wouldn't have been missed with a running EIS. 



Phil



Sent from my iPhone



 	  Quote: 	
		   On Feb 25, 2015, at 12:12 PM, Flysrv10 <flysrv10(at)gmail.com> wrote:

 

 

 

 Phil, I am assuming that the Cessna had the engine information available at start up and guessing that it still did not help you prevent the melt down. Yes, there are times that malfunction happens at the worst time but is it worth all the complexities to prevent a rare event. In my many yes and hrs of flying, I never witnessed one on my plane and others. 

 

 Sent from my iPhone

 

> On Feb 25, 2015, at 12:25 PM, Phillip Perry <philperry9(at)gmail.com> wrote:

> 

> 

> 

> Operating a dual dual system is really easy. There's very little that needs to be learned beyond throwing a switch.   It's good to know the system, but it's really not a burden.   The complexity is really a matter of understanding the wiring.  That's the part that most people get intimidated by. 

> 

> As far as EIS, we've always had oil pressure monitoring from the second he engine started it was just performed via an analog gauge.   I have seen Lycoming's that failed to produce oil pressure (or enough pressure to get in the green) after engine start.  That's why the gauge is there and every engine manual and pre-flight checklist says to start the engine, set the RPM, and confirm oil pressure in the green.   Without an operating EIS, you don't have RPM or pressure information. 

> 

> Also, I can personally attest to the value of seeing voltage information in addition to oil/engine information.  I melted down a C-152'a panel and caused a small fire when I was doing my flight training.  The starter bendix never disengaged from the flywheel and when I added power to adjust the RPM, the starter became an unregulated generator.   It dumped unregulated high voltages back into the electrical system smoking some equipment, lots of wires, and causing fire damage behind the panel.  It was a terrible experience. 

> 

> If I had voltage information from the start, I would have been alerted that there was higher than normal voltage on the buss and I would have known to shut it down and investigate more.

> 

> So there is value in having that information available.  In that cassette would have saved the FBO some $$ and kept their plane in service.   For me, it was just a lesson learned to check those voltages (with the alt off) while checking oil pressures after engine start. 

> 

> Phil

> 

> 

> 

> 

> 

> Sent from my iPhone

> 

>> On Feb 25, 2015, at 10:51 AM, Flysrv10 <flysrv10(at)gmail.com> wrote:

>> 

>> 

>> 

>> I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?  

>> 

>> I also wonder why everyone is making their system so complicated. 

>> 

>> Don't mean to criticize.  I am thinking that others have had experienced that I have not had and perhaps all the efforts are based on past events. 

>> 

>> Thanks. 

>> 

>> Do not archive. 

>> 

>> Sent from my iPhone

>> 

>>> On Feb 25, 2015, at 3:03 AM, Werner Schneider <glastar(at)gmx.net> wrote:

>>> 

>>> 

>>> 

>>> Wonder why most of the people are so heavily looking at the engine monitor being up on start?

>>> On my Glastar I have in // to the EMS a pressure switch which comes alive I think with 25 or 30 psi, that linked

>>> to a LED shows me immediately on start up if the oil pressure comes up and it is a very cheap (and the only)

>>> backup for my EMS.

>>> 

>>> And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.

>>> 

>>> Cheers Werner

>>> 

>>>> On 25.02.2015 04:19, nukeflyboy wrote:

>>>> ...  On engine start you will want to see your engine monitor so reboots are a PITA.

Mauledriver(at)nc.rr.com
Guest

Posted: Wed Feb 25, 2015 11:08 am Post subject: PC680 vs PC925

On 2/25/2015 11:51 AM, Flysrv10 wrote:

 	  Quote: 	
		   



 I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?

I have to admit that I was never concerned about oil pressure at 
	


start-up until building and maintaining my own plane.  In normal 

operations - no concerns.  Right after an oil change, I like to look at 

the pressure gauge.  After pulling and remounting the engine (for the 

nosewheel SB), I really needed to look at the gauge.  A single, stupid 

no-oil pressure start would be $$$$$$

 	  Quote: 	
		     



 I also wonder why everyone is making their system so complicated.

A simple one battery, single alternator system  works fine.  Some 
	


built-in backup batteries for critical avionics can do the rest, no 

question.



Some people put more robust systems in because they are running 

electronic ignition systems.  I'm running dual mags.



The dual bus/batt/alternator system (the Z-14 in my case) is very robust 

and capable and a bit more challenging to design and install.  But it is 

simple to use and pretty much immune to unexpected or non-standard 

operations.  My experiences flying IFR in my old Maule drove a lot of 

how I wanted the '10 to operate.  The complexity actually makes it 

simpler to operate and more reliable.



The main thing I was after was the ability to run the panel as needed 

before the start without concern for the subsequent engine start.  

That's SOP for me.



But I've had a  couple of experiences where sitting on the ground with 

the engine off  and with the panel fired up was more than desirable - 

and knowing that I can still fire up the engine and go was a big deal.



For example, post Katrina KNEW when there were no Nexrad terminals 

available in the temporary FBO building - waiting in the plane, in the 

rain, watching Nexrad and  waiting for a break in the line of cells was 

the only way I could get out.



Or sitting at Oshkosh waiting for the runway to open after an incident - 

run the engine for an hour+ and you will probably have to pull a plug or 

two.  Shut down, watch the weather and listen to the radio ready to 

depart ASAP.



Or sitting at a uncontrolled airport waiting for in IFR clearance for a 

departure into  IMC - sometimes that wait can go on for a long time if 

there are incoming planes, best to shut down and monitor. Or sitting at 

a KEWR or KHPN when things are backed up and the airliners are being 

shown the penalty box (usually you just keep the engine running in these 

cases).



I'm getting ready for my 2nd trip to the out islands of the Bahamas.  

Lose an alternator or have a cell short and you are stuck... nothing 

that $$$$ and days won't fix.  I'd probably fly it out.



The 2nd battery can be the poor pilot's APU.  Nice, but certainly not 

required.



 	  Quote:

jdriggs49(at)msn.com
Guest

Posted: Wed Feb 25, 2015 11:10 am Post subject: PC680 vs PC925

It's really easy and simple to wire in an indicator light that will illuminate if the starter is stuck on. There are examples out there of wiring diagrams and I'm using one of them.



 	  Quote: 	
		   From: flysrv10(at)gmail.com

 Subject: Re: RV10-List: Re: PC680 vs PC925

 Date: Wed, 25 Feb 2015 13:12:09 -0500

 To: rv10-list(at)matronics.com

 

 --> RV10-List message posted by: Flysrv10 <flysrv10(at)gmail.com>

 

 Phil, I am assuming that the Cessna had the engine information available at start up and guessing that it still did not help you prevent the melt down. Yes, there are times that malfunction happens at the worst time but is it worth all the complexities to prevent a rare event. In my many yes and hrs of flying, I never witnessed one on my plane and others. 

 

 Sent from my iPhone

 

 > On Feb 25, 2015, at 12:25 PM, Phillip Perry <philperry9(at)gmail.com> wrote:

 > 

 > --> RV10-List message posted by: Phillip Perry <philperry9(at)gmail.com>

 > 

 > Operating a dual dual system is really easy. There's very little that needs to be learned beyond throwing a switch.   It's good to know the system, but it's really not a burden.   The complexity is really a matter of understanding the wiring.  That's the part that most people get intimidated by. 

 > 

 > As far as EIS, we've always had oil pressure monitoring from the second he engine started it was just performed via an analog gauge.   I have seen Lycoming's that failed to produce oil pressure (or enough pressure to get in the green) after engine start.  That's why the gauge is there and every engine manual and pre-flight checklist says to start the engine, set the RPM, and confirm oil pressure in the green.   Without an operating EIS, you don't have RPM or pressure information. 

 > 

 > Also, I can personally attest to the value of seeing voltage information in addition to oil/engine information.  I melted down a C-152'a panel and caused a small fire when I was doing my flight training.  The starter bendix never disengaged from the flywheel and when I added power to adjust the RPM, the starter became an unregulated generator.   It dumped unregulated high voltages back into the electrical system smoking some equipment, lots of wires, and causing fire damage behind the panel.  It was a terrible experience. 

 > 

 > If I had voltage information from the start, I would have been alerted that there was higher than normal voltage on the buss and I would have known to shut it down and investigate more.

 > 

 > So there is value in having that information available.  In that cassette would have saved the FBO some $$ and kept their plane in service.   For me, it was just a lesson learned to check those voltages (with the alt off) while checking oil pressures after engine start. 

 > 

 > Phil

 > 

 > 

 > 

 > 

 > 

 > Sent from my iPhone

 > 

 >> On Feb 25, 2015, at 10:51 AM, Flysrv10 <flysrv10(at)gmail.com> wrote:

 >> 

 >> --> RV10-List message posted by: Flysrv10 <flysrv10(at)gmail.com>

 >> 

 >> I wonder why everyone is concerned over oil pressure at startup?  If the plane behaved when it was shut down, why would it not at start up?  

 >> 

 >> I also wonder why everyone is making their system so complicated. 

 >> 

 >> Don't mean to criticize.  I am thinking that others have had experienced that I have not had and perhaps all the efforts are based on past events. 

 >> 

 >> Thanks. 

 >> 

 >> Do not archive. 

 >> 

 >> Sent from my iPhone

 >> 

 >>> On Feb 25, 2015, at 3:03 AM, Werner Schneider <glastar(at)gmx.net> wrote:

 >>> 

 >>> --> RV10-List message posted by: Werner Schneider <glastar(at)gmx.net>

 >>> 

 >>> Wonder why most of the people are so heavily looking at the engine monitor being up on start?

 >>> On my Glastar I have in // to the EMS a pressure switch which comes alive I think with 25 or 30 psi, that linked

 >>> to a LED shows me immediately on start up if the oil pressure comes up and it is a very cheap (and the only)

 >>> backup for my EMS.

 >>> 

 >>> And then my Dynon D10 EMS does take less then 10 sec to reboot on start up.

 >>> 

 >>> Cheers Werner

 >>> 

 >>>> On 25.02.2015 04:19, nukeflyboy wrote:

 >>>> ...  On engine start you will want to see your engine monitor so reboots are a PITA.

 > 

 > 

 > 

 > 

 > 

=====================
	


 	  Quote: 	
		   _=============

 

 

 


	


 		 	   		  

  [quote][b]

Kellym

Joined: 10 Jan 2006
Posts: 1706
Location: Sun Lakes AZ

Posted: Wed Feb 25, 2015 12:56 pm Post subject: PC680 vs PC925

I don't know what other EFIS brands are doing, but Dynon uses one 

Lithium rechargeable per screen, and the software carefully manages the 

recharge. It is not possible to recharge any other way than being 

installed and screen on.

As for the airframe ground return, every Cessna and Piper and Mooney use 

airframe for ground return. On my Mooney it is just like the RV-10, with 

battery behind baggage compartment, and I have one of those wimpy Skytec 

flyweight starters that draws well over 200 amps to crank my 200 hp 

Lycoming. Works fine as long as all connections are clean and tight. #2 

positive wire, and airframe ground. The only arena that you do NOT want 

to use airframe for ground is the electronics. I probably will add a 

ground strap from engine mount to firewall, as I do not like Van's 

design of using the engine mount itself as primary ground path.



On 2/25/2015 11:28 AM, Linn Walters wrote:

[quote]

 Like I said, a small, sealed Gel Cell battery as a backup will fix 

 those 'brownouts'.

 I also see starting problems stemming from the use of the airframe as 

 a ground return for the battery.  I ran a #2 cable to the engine for a 

 ground.

 Linn ..... mounting wheel pants



 On 2/25/2015 10:13 AM, Kelly McMullen wrote:

> 

>

> The problem during start is NOT transient spikes, especially of 

> higher voltage. The problem is LOW voltage from the starter current 

> draw.

> Most avionics today are rated for 8 - 32v because they have their own 

> power supply controlling voltage to what the individual circuit 

> boards need.

> 1960s avionics had first generation transistors and ICs that were 

> very sensitive to low voltage and were easily fried by same. But the 

> industry ASSUMED that there were high voltage spikes, so implemented 

> avionics master switches. It solved the problem, without ever 

> determining what the real failure mode was.

>

> On 2/25/2015 7:57 AM, Linn Walters wrote:

>> 

>>

>> You have a point, but the starting transient problem pretty much 

>> goes away when you add the reverse current diode across the master 

>> and start contactor coils.

>> Also, modern electronics (should) have switching power supplies 

>> which are fairly immune to those reverse-current spikes.

>> I put dual MGL Odyssey panels in my RV-10 (not flying yet) panel and 

>> each one has it's own backup battery ...... a sealed battery for 

>> that goes into exit lights.

>>

>> There isn't that much current draw for the panels themselves.

>>

>> Having said all that, I wouldn't want to risk a Garmin repair cost 

>> either!!

>> Linn ..... mounting wheel pants

>>

>> On 2/25/2015 9:24 AM, Carl Froehlich wrote:

>>> 

>>> <carl.froehlich(at)verizon.net>

>>>

>>> Yep - that is what I do.  The panel comes up after engine start.  

>>> While

>>> Dynon assured me the SkyView system is not at risk for engine start 

>>> voltage

>>> transients, Garmin provided no such guarantee.  The last damn thing 

>>> I want

>>> is to have to engage Garmin again to fix the GTN-650.  In any case, 

>>> why

>>> expose these high price electronics to such transients if not needed?

>>>

>>> Carl

>>>

>>> --

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

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