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PC680 vs PC925
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rvdave

Joined: 24 Jan 2009
Posts: 191

Posted: Mon Feb 23, 2015 9:19 pm Post subject: PC680 vs PC925

I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

_________________
Dave Ford
Cadillac, MI

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Mon Feb 23, 2015 11:29 pm Post subject: PC680 vs PC925

There are folks running both successfully.  My system is dual batt with dual alts and have a 680 on both.  However I have a contractor that will allow me to bind them together in parallel if needed.  With that setup I can get redundancy, 1360 for cold starting if required, and a backup starting battery in the event I show up to the hangar and have a dead primary battery. 



My first engine start hasn't occurred yet, but I'm not worried about the 680  doing it based on other people's success with it in the -10. 



I only point this out in case you happen to be running a dual-dual system.  If I were single battery though and in a cold climate I'd have a hard time turning my back on the 925 with all the lifting power the -10 provides. 



Phil

Sent from my iPhone



 	  Quote: 	
		   On Feb 23, 2015, at 11:19 PM, rvdave <rv610dave(at)gmail.com> wrote:

 

 

 

 I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

 

 --------

 Dave Ford

 RV6 for sale

 RV10 building

 Cadillac, MI

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438635#438635

flysrv10(at)gmail.com
Guest

Posted: Tue Feb 24, 2015 12:47 am Post subject: PC680 vs PC925

I have a single 680 and it actually cranks better in the cold weather due to less resistance in the wiring (I guess).  I crank faster at temp of 20 deg in New Mexico than in Florida at 80 deg.

do not archive.

 	  Quote: 	
		   On Feb 24, 2015, at 2:26 AM, Phillip Perry <philperry9(at)gmail.com> wrote:

 There are folks running both successfully.  My system is dual batt with dual alts and have a 680 on both.  However I have a contractor that will allow me to bind them together in parallel if needed.  With that setup I can get redundancy, 1360 for cold starting if required, and a backup starting battery in the event I show up to the hangar and have a dead primary battery. 

 My first engine start hasn't occurred yet, but I'm not worried about the 680  doing it based on other people's success with it in the -10. 

 I only point this out in case you happen to be running a dual-dual system.  If I were single battery though and in a cold climate I'd have a hard time turning my back on the 925 with all the lifting power the -10 provides. 

 Phil

 Sent from my iPhone

> On Feb 23, 2015, at 11:19 PM, rvdave <rv610dave(at)gmail.com> wrote:

> 

> 

> 

> I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, bu!

 t !

> interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

> 

> --------

> Dave Ford

> RV6 for sale

> RV10 building

> Cadillac, MI

> 

> 

> 

> 

> Read this topic online here:

> 

> http://forums.matronics.com/viewtopic.php?p=438635#438635

> 

> 

> 

> 

> 

> 

> 

> 

> 

>

rleffler

Joined: 05 Nov 2006
Posts: 680

Posted: Tue Feb 24, 2015 2:19 am Post subject: PC680 vs PC925

I have gone through two winters with a pair of 680s.   They work like a champ.   Most of the time, I just start off a single battery.    I do have the capability, like Phil described, to put the batteries in parallel for more cranking power.



With winter starts, I've found that the battery isn't the most critical item.    For me, it's been oil temperature.    I've got a Reiff cylinders and a sump heater.   If I preheat the engine long enough to get to 60+ degrees, the engine starts right away.    The colder the oil has been, the more blades it takes to start, which in turn requires more current to run the starter.   I don't leave the heater on all the time and I can control it remotely via cell phone.



Bob



Sent from my iPad



 	  Quote: 	
		   On Feb 24, 2015, at 12:19 AM, rvdave <rv610dave(at)gmail.com> wrote:

 

 

 

 I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

 

 --------

 Dave Ford

 RV6 for sale

 RV10 building

 Cadillac, MI

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438635#438635

_________________
Bob Leffler
N410BL - Phase I
http://mykitlog.com/rleffler

partner14

Joined: 12 Jan 2008
Posts: 540
Location: Granbury Texas

Posted: Tue Feb 24, 2015 3:50 am Post subject: PC680 vs PC925

Plane flies better with wt in the back anyway.  I started out 700+ hours ago with 2 680's, but now have one 680 and one 925.  A lot depends on the compression of your engine, and where you live.  Since it does get cold here, and I have 9.5:1 compression, the change was a good one.

Don McDonald

        From: rvdave <rv610dave(at)gmail.com>

 To: rv10-list(at)matronics.com 

 Sent: Monday, February 23, 2015 11:19 PM

 Subject: PC680 vs PC925

--> RV10-List message posted by: "rvdave" <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>

I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

--------

Dave Ford

RV6 for sale

RV10 building

Cadillac, MI

Read this topic online here:

http://forums.matronics.com/viewtopic.php?pcs.com/Navigator?RV10-List" target="_blank">http://www.matronics.com/Navi               - MATRONICS WEB FORUMS -http

 [quote][b]

_________________
Don A. McDonald
40636

cgroote1(at)yahoo.com
Guest

Posted: Tue Feb 24, 2015 4:07 am Post subject: PC680 vs PC925

I replaced the 680 (never failed, but on occasion marginal) with a 925. If you want no worries, go the 925 route.

johngoodman

Joined: 18 Sep 2006
Posts: 530
Location: GA

Posted: Tue Feb 24, 2015 5:11 am Post subject: Re: PC680 vs PC925

I have a 925 and a 680 in the back. Of course, neither work very well if you leave the battery switch on.................



John

_________________
#40572 Phase One complete in 2011

rvdave

Joined: 24 Jan 2009
Posts: 191

Posted: Tue Feb 24, 2015 5:50 am Post subject: Re: PC680 vs PC925

 	  Quote: 	
		  However I have a contractor that will allow me to bind them together in parallel if needed. 	


 	  Quote: 	
		     I do have the capability, like Phil described, to put the batteries in parallel for more cranking power.

	


Am considering a second contactor to connect the batteries for start if necessary. What is being used for the contactor switch?  Using a start or master contactor?   Are you connecting the second contactor via #2, 4, 6 wire(?) from battery, contactor to the primary buss or the primary starter contactor?

 	  Quote: 	
		   Plane flies better with wt in the back anyway 	




I can foresee the way my wife packs vs me is about a 4:1 ratio on other trips so I'll have no problem with weight in the back, hence the firewall battery for cg and loading issues.

_________________
Dave Ford
Cadillac, MI

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

Posted: Tue Feb 24, 2015 6:32 am Post subject: PC680 vs PC925

On 2/24/2015 8:50 AM, rvdave wrote:

       snip

       [quote]

Am considering a second contactor to connect the batteries for start if necessary. What is being used for the contactor switch?  Using a start or master contactor?   Are you connecting the second contactor via #2, 4, 6 wire(?) from battery, contactor to the primary buss or the primary starter contactor?



The master contactor is a long term 'on' device.  The start contactor is a short term 'on' device.  So, no matter where in your installation you put a contactor, use this guideline for choosing the proper one.



IMHO, unless you plan on leaving the two batteries connected in parallel for any length of time, the start contactor is better, and #2 wire is best for any start application.



Linn

[b]

tganster

Joined: 23 Oct 2007
Posts: 28

Posted: Tue Feb 24, 2015 6:46 am Post subject: PC680 vs PC925

Dave,



  We have been flying our 10 for almost 2 years equipped with two 680's out of CLI in northern WI. The IO540 will start fine on one battery but during the colder months I start on two because things are a bit stiff at -10 below. We never have a problem with the EFIS dropping out.    Unfortunately we will be heading home from Tuscon on Thursday back to below zero weather.



Tom & Dawn Ganster

N104TD CLI



Sent from my iPad



 	  Quote: 	
		   On Feb 23, 2015, at 10:19 PM, rvdave <rv610dave(at)gmail.com> wrote:

 

 

 

 I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

 

 --------

 Dave Ford

 RV6 for sale

 RV10 building

 Cadillac, MI

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438635#438635

_________________
Tom Ganster 40778 Fuselage

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Tue Feb 24, 2015 7:05 am Post subject: PC680 vs PC925

Dave,

B & C sells a pre-wired cross-feed contactor; meaning that it already has the diodes installed across the terminals.Â  That is the contactor I used in my airplane.

http://www.bandc.biz/prewiredcross-feedcontactor.aspx

It was designed around the AeroElectric Z-14 basic architecture. Â  If you don't have a copy of his book, it's worth the few dollars to purchase primarily for the diagrams.Â  However those architecture diagrams are also available online.Â  Z14 has two links because it spans a couple of .pdf pages. Â 

http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/

All of my connections between the batteries and between the batteries and the starter are #2.Â  To clarify, my primary starting battery is #2 from the battery to the starter.Â  My secondary battery is #2 across the cross-feed to my primary battery.Â  And, because there is less load (no starting load) directly off my second buss, I run #8 forward from the secondary battery to the components it powers in the panel.Â  Does that make sense?

I thought I had a better photo of the battery area, but apparently I don't.Â  Next time I'm out at the hangar I'll have to try and grab them. Â  But here's what I have showing some of the finished wiring and also another showing the battery mount modifications.Â  Both of the master contactors and the cross-feed contactors are in the back.Â  The starter contactor is still on the firewall.

Phil

[img]https://scontent-dfw.xx.fbcdn.net/hphotos-xap1/v/t1.0-9/1975094_10204232741572639_7221936053270137686_n.jpg?oh=4bf35d8cf062fc88f60c23d3cc43b06b&oe=558C8A49[/img]

[img]https://scontent-dfw.xx.fbcdn.net/hphotos-xfp1/v/t1.0-9/10702015_10204017824399844_647456238164610391_n.jpg?oh=697e2969624afa6d86ef00bf75c096dc&oe=554EFE2E[/img]

Â Â 

On Tue, Feb 24, 2015 at 7:50 AM, rvdave <rv610dave(at)gmail.com (rv610dave(at)gmail.com)> wrote:

[quote]--> RV10-List message posted by: "rvdave" <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>

 > However I have a contractor that will allow me to bind them together in parallel if needed.

 >Â  Â  I do have the capability, like Phil described, to put the batteries in parallel for more cranking power.

 >

 Am considering a second contactor to connect the batteries for start if necessary. What is being used for the contactor switch?Â  Using a start or master contactor?Â  Â Are you connecting the second contactor via #2, 4, 6 wire(?) from battery, contactor to the primary buss or the primary starter contactor?

 >Â  Plane flies better with wt in the back anyway

 I can foresee the way my wife packs vs me is about a 4:1 ratio on other trips so I'll have no problem with weight in the back, hence the firewall battery for cg and loading issues. 

 --------

 Dave Ford

 RV6 for sale

 RV10 building

 Cadillac, MI

 Read this topic online here:

 http://forums.matronics.com/viewtopic.php?p=438648#438648

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 [b]

gengrumpy

Joined: 07 May 2013
Posts: 131
Location: Tullahoma, TN

Posted: Tue Feb 24, 2015 7:46 am Post subject: PC680 vs PC925

I have 2x680s in my plane.  Starting on just one of them is almost impossible due to the high compression of the engine, so I tie both of mine together for the start.



I would look to using the 925 if I were doing it all over again.



grumpy

N184jm



 	  Quote: 	
		   On Feb 23, 2015, at 11:19 PM, rvdave <rv610dave(at)gmail.com> wrote:

 

 

 

 I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

 

 --------

 Dave Ford

 RV6 for sale

 RV10 building

 Cadillac, MI

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438635#438635

davidsoutpost(at)comcast.
Guest

Posted: Tue Feb 24, 2015 8:05 am Post subject: PC680 vs PC925

I have two 680's in my RV-10 with independent master switch's.  One single 680 will turn the IO-540 over just fine.  I usually use both though for starting, then switch one Off after it starts.  Charging both batteries hooked up together is not a good idea without using a battery isolator which I do not have.  It can lead to early battery failure.  After I am airborne a few minutes, I swap to the battery off line to charge it back up.  Both batteries are mounted in the plans location and the added weight of the second battery helps out for the CG on my plane.



David Clifford



Howell,  MI

RV-10



N959RV



 



From: "rvdave" <rv610dave(at)gmail.com>

To: rv10-list(at)matronics.com

Sent: Tuesday, February 24, 2015 12:19:17 AM

Subject: PC680 vs PC925

--> RV10-List message posted by: "rvdave" <rv610dave(at)gmail.com>

I know theses are both good batteries that some are using.  Obviously the 925 is much better for starting but wondering if anyone has experience using the 680 for starting?  I've been using one on a 4 cyl Lycoming with no problem but wondering about the 6 cyl?  I just did some testing on a Chevy van 6 cyl I have that needed a new battery, I have an older 10 year old 680 battery I had on the bench for shop projects I decided to try.  It does start my van in the winter cold but marginally because although it will turn over the engine adequately the clock will also reset to 12 o'clock sometimes, so I know this is marginal but may be attributed to the 10 year plus life.  So I ordered a 925 from amazon got a great deal, free freight and put in in my van to check it.  What a noticeable cranking difference--with authority!   Recently with this cold snap in Mi had a minus 27 deg morning and there was no hesitation with the 925 starting the van.  Sold on the 925 as very capable, but !

 interested in the weight savings and I may have to get another new 680 to do the same test but thought I'd check others' experience with the 680 for starting.  Anyone with experience?

--------

Dave Ford

RV6 for sale

RV10 building

Cadillac, MI

Read this topic online here:

http://forums.matronics.com/viewtopic.php?p=438635#438635



 [quote][b]

carl.froehlich(at)verizon
Guest

Posted: Tue Feb 24, 2015 11:11 am Post subject: PC680 vs PC925

I'll have to disagree with any downside of having two batteries in parallel with a single alternator as a normal mode of operation.  Side note - this is a common set up for some trucks.



As all batteries have some internal resistance, charge rate is dependent on terminal voltage (for typical alternator configuration).  If more than one battery is in parallel with the alternator, the resistance seen by the alternator is that of parallel resistors.  For identical batteries this will be one half of a single battery internal resistance.  As resistance seen by the alternator drops, alternator current increases.  As alternator current increases, charge voltage will drop (alternator output voltage drops as alternator output current increases).  For you engineers out there you might remember the "house curve" to model load on machines operating in parallel.



The only caveat I'll add is that the batteries should have similar chemistry

Mauledriver(at)nc.rr.com
Guest

Posted: Tue Feb 24, 2015 2:33 pm Post subject: PC680 vs PC925

I too have a Bob Nuckolls Z-14       configured exactly as Phil describes below right down to cable       sizes.Â  Works great and I highly recommend this approach.

       

       Single battery starts with the 680 are okay but not confidence       inspiring. It's not something I'd be comfortable depending on if       there was a chance that I had to draw down the 680 for some reason       before the start.Â  I do have the light weight starter which others       have pointed out is not the best for crisp starts of the IO540.Â        However, with (2) 680s, I am totally confident that the engine       will start independent of any pre-start activities.Â  That's what I       was after with the Z-14 and I got it.

       

       I initially operated by doing the engine start on one battery then       cross linking the two batteries, alternators and buses once       underway.Â  My reasons were 1) avoiding rebooting of the (3) EFISes       which ran on the other battery/bus and 2) having everything cross       connected so that any electrical failure would occur without an       immediate impact on my panel.

       

       After much back and forth with Nuckolls, he pointed out that this       was bass ackwards.Â  Instead I should start using both batteries to       minimize the impact on the batteries (starting is probably the       most stressful moments for the battery).Â  And then after the start       I should run with the two buses unlinked so that any failures       would be made apparent when they occur.Â  Linking the 2 buses would       be part of the recovery from such a failure.Â  Makes sense and I've       been running that way ever since.

       

       Bill "watching the white stuff fall in NC!!??" Watson

       

       On 2/24/2015 10:01 AM, Phillip Perry wrote:

     

     [quote]       Dave,         

         

         B & C sells a pre-wired cross-feed contactor; meaning           that it already has the diodes installed across the           terminals.Â  That is the contactor I used in my airplane.

         http://www.bandc.biz/prewiredcross-feedcontactor.aspx

         

         

         It was designed around the AeroElectric Z-14 basic           architecture. Â  If you don't have a copy of his book, it's           worth the few dollars to purchase primarily for the diagrams.Â            However those architecture diagrams are also available           online.Â  Z14 has two links because it spans a couple of .pdf           pages. Â 

         http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/

         

         

         All of my connections between the batteries and between the           batteries and the starter are #2.Â  To clarify, my primary           starting battery is #2 from the battery to the starter.Â  My           secondary battery is #2 across the cross-feed to my primary           battery.Â  And, because there is less load (no starting load)           directly off my second buss, I run #8 forward from the           secondary battery to the components it powers in the panel.Â            Does that make sense?

           

           I thought I had a better photo of the battery area, but           apparently I don't.Â  Next time I'm out at the hangar I'll have           to try and grab them. Â  But here's what I have showing some of           the finished wiring and also another showing the battery mount           modifications.Â  Both of the master contactors and the           cross-feed contactors are in the back.Â  The starter contactor           is still on the firewall.

         

         

         Phil

         

         

         

         

         

         

         [img]mailbox:///C:/Users/Bill%20Watson/AppData/Roaming/Thunderbird/Profiles/s8b4lrvu.default/Mail/pop-server.nc.rr.com/Drafts?number=4005853&oh=4bf35d8cf062fc88f60c23d3cc43b06b&oe=558C8A49[/img]

         

         

         

         [img]mailbox:///C:/Users/Bill%20Watson/AppData/Roaming/Thunderbird/Profiles/s8b4lrvu.default/Mail/pop-server.nc.rr.com/Drafts?number=4005853&oh=697e2969624afa6d86ef00bf75c096dc&oe=554EFE2E[/img]

         

         Â Â 

       

       

         On Tue, Feb 24, 2015 at 7:50 AM, rvdave           <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>           wrote:

            	  Quote: 	
		  -->             RV10-List message posted by: "rvdave" <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>

             

             

             > However I have a contractor that will allow me to bind             them together in parallel if needed.

             

             

             >Â  Â  I do have the capability, like Phil described, to             put the batteries in parallel for more cranking power.

             >

             

             Am considering a second contactor to connect the batteries             for start if necessary. What is being used for the contactor             switch?Â  Using a start or master contactor?Â  Â Are you             connecting the second contactor via #2, 4, 6 wire(?) from             battery, contactor to the primary buss or the primary             starter contactor?

             

             >Â  Plane flies better with wt in the back anyway

             

             

             I can foresee the way my wife packs vs me is about a 4:1             ratio on other trips so I'll have no problem with weight in             the back, hence the firewall battery for cg and loading             issues. 

             

             --------

             Dave Ford

             RV6 for sale

             RV10 building

             Cadillac, MI

             

             

             

             

             Read this topic online here:

             

             http://forums.matronics.com/viewtopic.php?p=438648#438648

             

             

             

             

             

             

             

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philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Tue Feb 24, 2015 4:38 pm Post subject: PC680 vs PC925

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.  

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).

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. 

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

Phil



Sent from my iPhone



On Feb 24, 2015, at 4:30 PM, Bill Watson <Mauledriver(at)nc.rr.com (Mauledriver(at)nc.rr.com)> wrote:

[quote]                   I too have a Bob Nuckolls Z-14       configured exactly as Phil describes below right down to cable       sizes.  Works great and I highly recommend this approach.

       

       Single battery starts with the 680 are okay but not confidence       inspiring. It's not something I'd be comfortable depending on if       there was a chance that I had to draw down the 680 for some reason       before the start.  I do have the light weight starter which others       have pointed out is not the best for crisp starts of the IO540.        However, with (2) 680s, I am totally confident that the engine       will start independent of any pre-start activities.  That's what I       was after with the Z-14 and I got it.

       

       I initially operated by doing the engine start on one battery then       cross linking the two batteries, alternators and buses once       underway.  My reasons were 1) avoiding rebooting of the (3) EFISes       which ran on the other battery/bus and 2) having everything cross       connected so that any electrical failure would occur without an       immediate impact on my panel.

       

       After much back and forth with Nuckolls, he pointed out that this       was bass ackwards.  Instead I should start using both batteries to       minimize the impact on the batteries (starting is probably the       most stressful moments for the battery).  And then after the start       I should run with the two buses unlinked so that any failures       would be made apparent when they occur.  Linking the 2 buses would       be part of the recovery from such a failure.  Makes sense and I've       been running that way ever since.

       

       Bill "watching the white stuff fall in NC!!??" Watson

       

       On 2/24/2015 10:01 AM, Phillip Perry wrote:

     

      	  Quote: 	
		         Dave,         

         

         B & C sells a pre-wired cross-feed contactor; meaning           that it already has the diodes installed across the           terminals.  That is the contactor I used in my airplane.

         http://www.bandc.biz/prewiredcross-feedcontactor.aspx

         

         

         It was designed around the AeroElectric Z-14 basic           architecture.   If you don't have a copy of his book, it's           worth the few dollars to purchase primarily for the diagrams.            However those architecture diagrams are also available           online.  Z14 has two links because it spans a couple of .pdf           pages.  

         http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/

         

         

         All of my connections between the batteries and between the           batteries and the starter are #2.  To clarify, my primary           starting battery is #2 from the battery to the starter.  My           secondary battery is #2 across the cross-feed to my primary           battery.  And, because there is less load (no starting load)           directly off my second buss, I run #8 forward from the           secondary battery to the components it powers in the panel.            Does that make sense?

           

           I thought I had a better photo of the battery area, but           apparently I don't.  Next time I'm out at the hangar I'll have           to try and grab them.   But here's what I have showing some of           the finished wiring and also another showing the battery mount           modifications.  Both of the master contactors and the           cross-feed contactors are in the back.  The starter contactor           is still on the firewall.

         

         

         Phil

         

         

         

         

         

         

         [img]mailbox:///C:/Users/Bill%20Watson/AppData/Roaming/Thunderbird/Profiles/s8b4lrvu.default/Mail/pop-server.nc.rr.com/Drafts?number=4005853&oh=4bf35d8cf062fc88f60c23d3cc43b06b&oe=558C8A49[/img]

         

         

         

         [img]mailbox:///C:/Users/Bill%20Watson/AppData/Roaming/Thunderbird/Profiles/s8b4lrvu.default/Mail/pop-server.nc.rr.com/Drafts?number=4005853&oh=697e2969624afa6d86ef00bf75c096dc&oe=554EFE2E[/img]

         

           

       

       

         On Tue, Feb 24, 2015 at 7:50 AM, rvdave           <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>           wrote:

            	  Quote: 	
		  -->             RV10-List message posted by: "rvdave" <rv610dave(at)gmail.com (rv610dave(at)gmail.com)>

             

             

             > However I have a contractor that will allow me to bind             them together in parallel if needed.

             

             

             >    I do have the capability, like Phil described, to             put the batteries in parallel for more cranking power.

             >

             

             Am considering a second contactor to connect the batteries             for start if necessary. What is being used for the contactor             switch?  Using a start or master contactor?   Are you             connecting the second contactor via #2, 4, 6 wire(?) from             battery, contactor to the primary buss or the primary             starter contactor?

             

             >  Plane flies better with wt in the back anyway

             

             

             I can foresee the way my wife packs vs me is about a 4:1             ratio on other trips so I'll have no problem with weight in             the back, hence the firewall battery for cg and loading             issues. 

             

             --------

             Dave Ford

             RV6 for sale

             RV10 building

             Cadillac, MI

             

             

             

             

             Read this topic online here:

             

             http://forums.matronics.com/viewtopic.php?p=438648#438648

             

             

             

             

             

             

             

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[b]

nukeflyboy

Joined: 05 Jan 2008
Posts: 162
Location: Granbury, TX

Posted: Tue Feb 24, 2015 5:06 pm Post subject: Re: PC680 vs PC925

Phil,



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

_________________
Dave Moore
RV-6 built and sold
RV-10 built and flying

philperry9

Joined: 23 Nov 2011
Posts: 381

Posted: Tue Feb 24, 2015 5:31 pm Post subject: PC680 vs PC925

As I mentioned earlier, I haven't performed the first start yet so I can't put a stake in the ground with a definite claim.  However I don't believe there will be any issues with reboots on the EFIS' at the time of start.  



The way the design lays out, the current should never be interrupted during a start.  



Phil



Sent from my iPhone



 	  Quote: 	
		   On Feb 24, 2015, at 7:06 PM, nukeflyboy <flymoore(at)charter.net> wrote:

 

 

 

 Phil,

 

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

 

 --------

 Dave Moore

 RV-6 flying

 RV-10 QB - flying

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=438684#438684

nukeflyboy

Joined: 05 Jan 2008
Posts: 162
Location: Granbury, TX

Posted: Tue Feb 24, 2015 7:19 pm Post subject: Re: PC680 vs PC925

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 built and sold
RV-10 built and flying

Mauledriver(at)nc.rr.com
Guest

Posted: Tue Feb 24, 2015 7:28 pm Post subject: PC680 vs PC925

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

 	  Quote: 	
		   



 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.

 	  Quote: 	
		   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.

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