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graybeard
Joined: 20 Sep 2011
Posts: 33
Location: Grants Pass, OR
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 Posted: Fri Jan 27, 2012 11:29 am Post subject: battery selection |
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Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
[quote][b]
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carl.froehlich(at)verizon
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| Posted: Fri Jan 27, 2012 12:03 pm Post subject: battery selection |
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This is exactly what I have in my 8A (700 hrs), two PC625 batteries. The battery has almost identical performance to the PC680 but a much better form factor for my install. I have both mounted just aft of the firewall, one on each side. I too have an all electric panel. I have done tests to demonstrate the batteries will support 2 and ½ hours of IFR flight with no alternator (the design target). I change out one battery every two years just to make sure they are up to snuff (no battery is more than 4 years old). I have one of the old batteries in my lawn tractor now for 6 years – and it still cranks it right up after sitting all winter. I also am using two PC625s in my RV-10.
I mounted the ELT on the shelf. I also mount a 15 pound tool/survival bag on the shelf. It handles both with no issues (max G load so far is 4 from a poorly executed loop). The ELT antenna is mounted under the empennage fairing.
Carl
From: owner-rv8-list-server(at)matronics.com [mailto:owner-rv8-list-server(at)matronics.com] On Behalf Of Stan Loer
Sent: Friday, January 27, 2012 2:27 PM
To: rv8-list(at)matronics.com
Subject: battery selection
Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
http://forums.matronics.com[/url] - List Contribution Web Site -Matt Dralle, href="http://www.matronics.com/contribution">http://www.matronics.com/c=[/b] [/quote]
[quote][b]
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Larry Bowen
Joined: 09 Jan 2006
Posts: 802
Location: NC, USA
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| Posted: Fri Jan 27, 2012 12:05 pm Post subject: battery selection |
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Can't help you on the battery, I've only used the 680.
I'll have all glass and dual LSI in the RV-7, and I'm actually considering one alt and one battery. Crazy, or just practical? TBD...
In the RV-8, I put my Pointer ELT under the VS. No added structure needed and helped a little with fwd CG.
Cheers,
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 2:26 PM, Stan Loer <stazel(at)cpros.com (stazel(at)cpros.com)> wrote:
[quote] Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
| Quote: |
et="_blank">http://www.matronics.com/Navigator?RV8-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
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[b]
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_________________
Larry Bowen
RV-8 SOLD,
RV-7QB in progress... |
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carl.froehlich(at)verizon
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| Posted: Fri Jan 27, 2012 12:36 pm Post subject: battery selection |
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No backup battery on a LightSpeed ignition install is not practical.
For no a backup battery system (or one with a back up battery) a dual P-Mags install is a better approach. If you want, I can tell you the name of the person I gave my dual Lightspeeds to when I yanked them off my 8A (replaced with P-Mags). You can get them real cheap.
Carl
From: owner-rv8-list-server(at)matronics.com [mailto:owner-rv8-list-server(at)matronics.com] On Behalf Of Larry Bowen
Sent: Friday, January 27, 2012 3:03 PM
To: rv8-list(at)matronics.com
Subject: Re: battery selection
Can't help you on the battery, I've only used the 680.
I'll have all glass and dual LSI in the RV-7, and I'm actually considering one alt and one battery. Crazy, or just practical? TBD...
In the RV-8, I put my Pointer ELT under the VS. No added structure needed and helped a little with fwd CG.
Cheers,
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 2:26 PM, Stan Loer <stazel(at)cpros.com (stazel(at)cpros.com)> wrote:
Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
| Quote: | | et="_blank">http://www.matronics.com/Navigator?RV8-Listtp://forums.matronics.com_blank">http://www.matronics.com/contribution |
0123456789 | Quote: | | et="_blank">http://www.matronics.com/Navigator?RV8-List |
0 | Quote: | | et="_blank">http://www.matronics.com/Navigator?RV8-List |
1 | Quote: | | et="_blank">http://www.matronics.com/Navigator?RV8-List |
2 | Quote: | | et="_blank">http://www.matronics.com/Navigator?RV8-List |
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[quote][b]
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Larry Bowen
Joined: 09 Jan 2006
Posts: 802
Location: NC, USA
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| Posted: Fri Jan 27, 2012 12:59 pm Post subject: battery selection |
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I'm already committed to the dual LSI. PMags were still wet behind the ears when I made the decision.
Alternator is primary, main battery is backup. How is that not practical? Educate me.
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 3:33 PM, Carl Froehlich <carl.froehlich(at)verizon.net (carl.froehlich(at)verizon.net)> wrote:
[quote]
No backup battery on a LightSpeed ignition install is not practical.
For no a backup battery system (or one with a back up battery) a dual P-Mags install is a better approach. If you want, I can tell you the name of the person I gave my dual Lightspeeds to when I yanked them off my 8A (replaced with P-Mags). You can get them real cheap.
Carl
From: owner-rv8-list-server(at)matronics.com (owner-rv8-list-server(at)matronics.com) [mailto:owner-rv8-list-server(at)matronics.com (owner-rv8-list-server(at)matronics.com)] On Behalf Of Larry Bowen
Sent: Friday, January 27, 2012 3:03 PM
To: rv8-list(at)matronics.com (rv8-list(at)matronics.com)
Subject: Re: battery selection
Can't help you on the battery, I've only used the 680.
I'll have all glass and dual LSI in the RV-7, and I'm actually considering one alt and one battery. Crazy, or just practical? TBD...
In the RV-8, I put my Pointer ELT under the VS. No added structure needed and helped a little with fwd CG.
Cheers,
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 2:26 PM, Stan Loer <stazel(at)cpros.com (stazel(at)cpros.com)> wrote:
Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
0123 456 78901 23
4
[b]
| | - The Matronics RV8-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV8-List |
|
_________________
Larry Bowen
RV-8 SOLD,
RV-7QB in progress... |
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carl.froehlich(at)verizon
Guest
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| Posted: Fri Jan 27, 2012 2:18 pm Post subject: battery selection |
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In a single alternator, single battery install the battery is primary and the alternator charges the battery, it is not a backup to the battery. I few thoughts:
<![if !supportLists]>1. <![endif]>Look at where your alternator connects to your battery. I offer that there are at least two points in the system where a single post failing (loose, melted, shorted) takes down your entire electrical system. Not long ago a twin engine plane (two alternators and two batteries) had a total loss of electrical power when the common post on the master relay failed.
<![if !supportLists]>2. <![endif]>Look at the single post for ground on your battery. Again a single failure will lead to total loss of power.
<![if !supportLists]>3. <![endif]>Many alternator installs do not run well without a battery floating on them for reference (source) voltage. Some do, some don’t.
<![if !supportLists]>4. <![endif]>For a simple example your master relay fails open. Unless you have dedicated auxiliary feeds from the battery you have lost all power.
I suspect many dual battery installs have only increase capacity to offer, not added redundancy. Again the objective is to not have a single failure bring down all your power. It is the system that counts, not the individual components.
The most reliable electrical component in your plane is the battery. This is why I have two batteries feeding independent master relays and dedicated smaller relays for the panel, and a single alternator. The odds of an alternator failing (I had two go south in my 8A over the last 9 years) is way higher than a battery failing in flight. Now if you crank a battery(s) into the dirt and then take off hoping the alternator will charge it (before the alternator craps out), you are just asking for trouble.
For a dual Lightspeed install some sort of battery backup for the ignition is mandatory. The simple Panasonic battery with the diode isolation as illustrated in Klaus’ manual is the bare minimum. It will at least let you land at the closest runway instead of an engine out landing in a field. For an all electric panel, redundant power is mandatory as well.
BTW – I took a look at your website link. So you know, the Lightspeed ignition box generates some heat. As you have them mounted back to back you might want to give Klaus a call to see if this reduction in heat transfer surface is a problem or not. In my 8A I had them mounted aft of the fire wall on spacers to allow air to get at the back of the box. I also had insulation on the cabin side of the firewall to isolate engine heat.
Carl
From: owner-rv8-list-server(at)matronics.com [mailto:owner-rv8-list-server(at)matronics.com] On Behalf Of Larry Bowen
Sent: Friday, January 27, 2012 3:57 PM
To: rv8-list(at)matronics.com
Subject: Re: battery selection
I'm already committed to the dual LSI. PMags were still wet behind the ears when I made the decision.
Alternator is primary, main battery is backup. How is that not practical? Educate me.
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 3:33 PM, Carl Froehlich <carl.froehlich(at)verizon.net (carl.froehlich(at)verizon.net)> wrote:
No backup battery on a LightSpeed ignition install is not practical.
For no a backup battery system (or one with a back up battery) a dual P-Mags install is a better approach. If you want, I can tell you the name of the person I gave my dual Lightspeeds to when I yanked them off my 8A (replaced with P-Mags). You can get them real cheap.
Carl
From: owner-rv8-list-server(at)matronics.com (owner-rv8-list-server(at)matronics.com) [mailto:owner-rv8-list-server(at)matronics.com (owner-rv8-list-server(at)matronics.com)] On Behalf Of Larry Bowen
Sent: Friday, January 27, 2012 3:03 PM
To: rv8-list(at)matronics.com (rv8-list(at)matronics.com)
Subject: Re: battery selection
Can't help you on the battery, I've only used the 680.
I'll have all glass and dual LSI in the RV-7, and I'm actually considering one alt and one battery. Crazy, or just practical? TBD...
In the RV-8, I put my Pointer ELT under the VS. No added structure needed and helped a little with fwd CG.
Cheers,
--
Larry Bowen
Larry(at)BowenAero.com
http://BowenAero.com
On Fri, Jan 27, 2012 at 2:26 PM, Stan Loer <stazel(at)cpros.com (stazel(at)cpros.com)> wrote:
Has anyone installed the Odyssey PC625 battery? I know that the PC680 is more common, but I'm looking at a dual installation with one battery forward and the other aft. The 625 is slightly smaller and lighter than the 680. My 8 will be all electric, no steam gauges, and set up for day/night VFR, so a dual battery installation makes more sense to me than a back-up alternator. Seems to me that dual paralleled PC625 batteries should provide plenty of get-home power in case of an alternator failure, even at night, but my electrical expertise is limited and I'll take all the help I can get.
While I'm at it, a question re ELT mount locations. I've seen several mounted on the "hat shelf". This is tempting as it's very
convenient, but the shelf is kinda flimsy. Beef it up? I'm also looking at possibly mounting it on brackets off the side of the aft battery box. More complex, but maybe a better choice.
01
234567
890123456789012345
[quote][b]
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Larry Bowen
Joined: 09 Jan 2006
Posts: 802
Location: NC, USA
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| Posted: Sat Jan 28, 2012 5:55 am Post subject: battery selection |
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Thanks for the input Carl. You've got me thinking. I was mostly focused
on endurance, I have to admit.
I'm also using a VP-X which accommodates management of a second battery.
So I may decide to take advantage of that.
Klaus is the one that prompted me to consider one alt, one bat. His
website talks about the endurance of your main battery being enough to get
you home.
There are many single points of failure. Some of them are best addressed
by ongoing inspection and maintenance. Belt and suspenders vs simplicity..
| | - The Matronics RV8-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RV8-List |
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_________________
Larry Bowen
RV-8 SOLD,
RV-7QB in progress... |
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