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johnbright
Joined: 14 Dec 2011
Posts: 165
Location: Newport News, VA
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 Posted: Sun May 07, 2023 5:44 pm Post subject: shorted AGM battery |
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In 2019 there was a homebuilt tractor configuration two-place SBS aircraft with an EFI system that had an off-field landing. Nothing got bent, nobody got hurt, failed battery replaced, AC took off from the landing site.
Hearsay had the problem as a shorted Odyssey AGM battery.
But, Bob Nuckolls says:
"We used to see the occasional shorted cell in flooded batteries. This could cause a 12 volt battery to become a 10 volt battery. Remaining good cells then suffered overcharging.
RG batteries don't do this."
Saturday May 6, 2023 I met the pilot at a grass strip fly-in in Suffolk, VA. I've been wanting to ask him if it was the battery itself or something external to the battery across the terminals. Pilot says it's an Odyssey AGM that shorted internally, battery case swelled. (Pilot says it's either a PC925 or PC950 and Alan Kohler at Odyssey says it's either a PC950 or PC1100 so that makes it a PC950.)
Photo attached.
He saw the voltage drop to 13-1/2 and thought alternator problem, then it fell to 12-1/2 and he thought alternator offline, then the voltage continued to fall and when it got to 7 the engine stopped.
The battery box, located aft of the passenger compartment, was larger than the battery and some type of foam was used to fill the space.
The battery has been discarded so no autopsy possible.
Pilot says:
"I would estimate 1 year and 50 flights, ~100 hours on that battery.
Belt driven Plane Power alternator.
Two batteries in parallel.
Both batteries could be used to start the plane or power the main bus (this was before the diode was installed). I don't have a drawing of it."
He says there was some sort of contactor arrangement whereby the batteries could be paralled or not. He paralleled the batteries in flight when he noticed the EFI voltage falling.
This was a short local flight.
No electrical power schematic available.
My first theory is battery was depleted at takeoff and overheated due to thermal insulation value of the foam around it combined with high capacity alternator.
I'm wondering what Bob and others think.
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_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links
Last edited by johnbright on Mon May 08, 2023 10:58 am; edited 12 times in total |
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Tim Olson
Joined: 25 Jan 2007
Posts: 2872
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| Posted: Sun May 07, 2023 8:53 pm Post subject: shorted AGM battery |
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Is that for sure an odyssey? I haven't ever seen an odyssey that looked
like that, and I don't think they even have that
big white sticker on them. The individual cell caps aren't something
I've ever seen on an Odyssey either.
That said, I know Odyssey makes some battery types that I haven't ever
physically seen, but this one
just doesn't have any of the characteristics that I've seen before in
data sheets.
Tim
On 5/7/2023 8:44 PM, johnbright wrote:
| Quote: |
In 2019 there was a homebuilt tractor configuration two-place SBS aircraft with an EFI system that had an off-field landing. Nothing got bent, nobody got hurt, failed battery replaced, AC took off from the landing site.
Hearsay had the problem as a shorted Odyssey AGM battery. But, Bob Nuckolls says:
"We used to see the occasional shorted cell in flooded batteries. This could cause a 12 volt battery to become a 10 volt battery. Remaining good cells then suffered overcharging.
RG batteries don't do this."
Saturday May 6, 2023 I met the pilot at a grass strip fly-in in Suffolk, VA. I've been wanting to ask him if it was the battery itself or something external to the battery across the terminals. He says Odyssey AGM battery internal short, battery case swelled, photo attached.
He saw the voltage drop to 13-1/2 and thought alternator problem, then it fell to 12-1/2 and he thought alternator offline, then the voltage continued to fall and when it got to 7 the engine stopped.
The battery box, located aft of the passenger compartment, was larger than the battery and some type of foam was used to fill the space.
The battery has been discarded so no autopsy possible.
Pilot says:
"I would estimate 1 year and 50 flights, ~100 hours on that battery.
Belt driven Plane Power alternator.
Two batteries in parallel.
Both batteries could be used to start the plane or power the main bus (this was before the diode was installed). I don't have a drawing of it."
He says there was some sort of contactor arrangement whereby the batteries could be paralled or not, batteries in parallel as the voltage fell. He said he paralleled the batteries in flight when the EFI voltage began to fall.
This was a short local photo flight.
No electrical power schematic available.
My first theory is battery was depleted at takeoff and overheated due to thermal insulation value of the foam around it combined with high capacity alternator.
I'm wondering what Bob and others think.
--------
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright(at)yahoo.com, Newport News, Va
<a href="https://docs.google.com/document/d/1YOtPiA3AdUsQEYR4nodBESNAo21rxdnx4pFs7VxXfuI/edit" target="_blank">N1921R links</a>
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510746#510746
Attachments:
http://forums.matronics.com//files/img_0199_683.png
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johnbright
Joined: 14 Dec 2011
Posts: 165
Location: Newport News, VA
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| Posted: Mon May 08, 2023 4:45 am Post subject: Re: shorted AGM battery |
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| Tim Olson wrote: | Is that for sure an odyssey? I haven't ever seen an odyssey that looked like that, and I don't think they even have that big white sticker on them...
Tim |
Thanks Tim,
I sent the photo to Odyssey at odysseybattery(at)enersys.com to get a definitive answer whether or not it is an Odyssey battery. Maybe to the maintenance person all AGMs are "Odyssey".
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_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links |
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nuckolls.bob(at)aeroelect
Guest
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| Posted: Mon May 08, 2023 7:44 am Post subject: shorted AGM battery |
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| Quote: |
Thanks Tim,
I sent the photo to Odyssey at odysseybattery(at)enersys.com to get a definitive answer whether
or not it is an Odyssey battery. Maybe to the maintenance person all AGMs are "Odyssey". |
Exactly, that is not an Odyssey (Enersys) product.
I should have qualified that "RG batteries don't do that"
statement.
"PROPERLY MAINTAINED RG batteries in thoughtfully configured
power generation systems don't do that"
Over the years we've seen many examples of puffed up
batteries, both wet and AGM, some of which actually
suffered dynamic chemical events that started internal
fires.
http://aeroelectric.com/Pictures/Batteries/Internal_Fire/
http://aeroelectric.com/Pictures/Batteries/Odyssey_OV/
If the owner/operator of those products had carried out
legacy aviation preventative maintenance protocols,
those batteries would have been replaced long before
their innards began to 'disassemble' -OR-
In other cases, we've seen perfectly serviceable batteries
self-destruct after suffering abuse by a runaway alternator
not fitted with ov protection.
After a few decades of sifting through the
bits and pieces for all manner of catastrophic
failure, it's hard to recall any that were
not based on a failure to 'take care of business'.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=========
< Go ahead, make my day . . . >
< show me where I'm wrong. >
=================================
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
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johnbright
Joined: 14 Dec 2011
Posts: 165
Location: Newport News, VA
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| Posted: Mon May 08, 2023 10:26 am Post subject: Re: shorted AGM battery |
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I got a prompt response from Alan Kohler of Odyssey Battery.
| | - The Matronics AeroElectric-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:
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_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links |
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Tim Olson
Joined: 25 Jan 2007
Posts: 2872
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| Posted: Mon May 08, 2023 11:02 am Post subject: shorted AGM battery |
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Interesting, thanks for that! Learn something new every day.
I've never seen vent caps on the Odyssey. And never all black. But,
they explained that.
Tim
On 5/8/2023 1:26 PM, johnbright wrote:
| Quote: |
I got a prompt response from Alan Kohler of Odyssey Battery.
Hello,
That is an EnerSys / Odyssey Battery
All Odyssey are AGM Batteries
This one had a severe internal issue, and severe over-charging.
The heat is the only thing that can soften the plastic enough to deform and stay deformed.
Personally, I have never seen that exact model used in an Aircraft before.
It is definitely one of these 2:
https://www.odysseybattery.com/products/ods-agm30e-battery-pc950/
https://www.odysseybattery.com/products/ods-agm40e-battery-pc1100/
We sometimes use all-black plastic, instead of the red top. These are made in the UK, and the black plastic is easier to get.
Alan Kohler
Marketing Manager
ODYSSEY Battery
--------
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright(at)yahoo.com, Newport News, Va
<a href="https://docs.google.com/document/d/1YOtPiA3AdUsQEYR4nodBESNAo21rxdnx4pFs7VxXfuI/edit" target="_blank">N1921R links</a>
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510759#510759
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johnbright
Joined: 14 Dec 2011
Posts: 165
Location: Newport News, VA
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| Posted: Mon May 08, 2023 11:05 am Post subject: Re: shorted AGM battery |
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I can imagine the failed battery being depleted and the aircraft being started on the other battery followed by becoming airborne promptly and the main alternator putting a lot of energy into the depleted battery that was made to fit an oversize battery box by using foam spacers.
The replacement battery is an Odyssey PC680 that also uses foam spacers so the risk is still present. I'll communicate with the pilot about that.
| | - The Matronics AeroElectric-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:
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_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links |
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