X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 22 Jun 2010 07:39:37 -0400 Message-ID: X-Original-Return-Path: Received: from raven.ravenwebhosting.com ([72.9.254.67] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTPS id 4366169 for lml@lancaironline.net; Tue, 22 Jun 2010 06:39:28 -0400 Received-SPF: none receiver=logan.com; client-ip=72.9.254.67; envelope-from=paul@tbm700.com Received: from 208.36.91.184.cfl.res.rr.com ([184.91.36.208]:61531 helo=[192.168.1.105]) by raven.ravenwebhosting.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1OR0sV-00057I-Bs for lml@lancaironline.net; Tue, 22 Jun 2010 06:38:51 -0400 From: paul miller Mime-Version: 1.0 (Apple Message framework v1078) Content-Type: multipart/alternative; boundary=Apple-Mail-149-395702013 Subject: Re: [LML] Re: Odyssey batteries with very limited warranties X-Original-Date: Tue, 22 Jun 2010 06:38:48 -0400 In-Reply-To: X-Original-To: "Lancair Mailing List" References: X-Original-Message-Id: <7258425C-2DE2-45B6-8518-4EA9FD74EAE8@tbm700.com> X-Mailer: Apple Mail (2.1078) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - raven.ravenwebhosting.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tbm700.com X-Source: X-Source-Args: X-Source-Dir: --Apple-Mail-149-395702013 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 I'm with you completely Chris on the battery tender concept. I've been = using them on a VRLA Concorde battery that costs $1800. I received = more than 5 years life on the last battery. I maintain the Legacy = batteries on charge as well with a different make. =20 But testing is a different story and maintainers can't guarantee = capacity. Load testing is the only way to determine some faults. My = batteries failed under load in the Legacy but not on the ground. When I = pulled gear up everything died including my Avidynes. It took a lot of = investigation and help with B&C before we finally tracked it to a = problem with the Odyssey and they were replaced, I think they were 2-3 = years old. The starting amperage for the hydraulic pump caused the = battery to fail under load. My point was that for someone like Bob who = wanted to know his capacity, that test will give him a number and a = trend each year. But since you mention the discharge issue I have = calculated some figures and I am open to corrections and comments of = course. Assuming the PC925 discussed earlier, the 10-hour discharge rate = capacity is 27AH (2.7a for 10 hours). The 20 hour capacity is almost = identical at 28AH. The reserve capacity is 52 minutes at 25A discharge = rate so you have two bookends to use. If an owner wanted to discharge at 25A and got 80% or more of the 52 = minutes before voltage dropped to 10,5v then I would suggest that = battery is good. If the test was performed at a more conservative C10 rate (2.7A) then = the battery would have to stay above 10v for at least 8 hours (80% of 10 = hours). Since Odyssey provides those high and low amperage benchmarks I believe = you can determine remaining capacity using a wide range of rates and = keep those batteries at long as they perform. Paul On 2010-06-21, at 6:39 PM, Chris Zavatson wrote: > Paul, > Changing the discharge rate during a capacity check will alter the = results Going higher in current will yield less capacity while using = less current will produce a higher capacity. The battery has internal = resistance that also uses up power (turns into heat) during the = discharge test. This loss is roughly a squared function of the current, = therefore changing the discharge current will alter the results. =20 > =20 > I highly recommend keeping batteries on a maintainer while not in use. = Once I started using these, my batteries (Concorde 25XC) would retain = over 90% capacity even after five years of use. I can now replace them = based on calendar time instead of performance. > =20 > =20 > Chris Zavatson > N91CZ > 360std > www.N91CZ.com =20 >=20 > From: paul miller > To: lml@lancaironline.net > Sent: Mon, June 21, 2010 5:20:51 AM > Subject: [LML] Re: Odyssey batteries with very limited warranties >=20 > To avoid tossing a good battery you can do a test similar to that used = on our Concorde batteries. Take the amp-hour rating (C1) and draw a = load and measure the amps and time down to the threshold of 10v or 20v = depending on the battery. If we can get 80% of the rated A-H capacity = we keep it. But, we use a normal discharge rate in the airplane, not a = full draw at C1 as I think that is unnecessary. So, maybe something = like 20% of C1 discharging through some lights for example or a rate = that duplicates a discharge rate in the airplane in your worst condition = so that it will show up any faults under load. Take a measurement = every X minutes and get your capacity. I'd do it on the bench out of = the airplane and track the capacity between annuals. >=20 > We previously tossed these expensive batteries based on calendar life = but we can now leave them on condition using these tests. >=20 > Paul > On 2010-06-19, at 3:01 PM, Robert R Pastusek wrote: >=20 >> Robert Simon wrote: >> =20 >> Just had two of my four Odyssey PC680 batteries crap out after 2 = years of service although an identical set on the other buss are fine=85 >> =20 >> Robert, >> I have a similar setup in my IV-P and had planned to replace two of = the four batteries every two years, expecting them to last for four = years=85but I never looked at the expected/advertised life; I was just = following a practice used for lead/acid batteries. Two of my batteries = are coming up on two years old; the other pair are coming up on four = years, and I=92d planned to replace them during the condition inspection = next month. I=92d appreciate your thoughts/experience on this. >> Thanks, >> Bob >=20 >=20 >=20 --Apple-Mail-149-395702013 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252 I'm = with you completely Chris on the battery tender concept.  I've been = using them on a VRLA Concorde battery that costs $1800.    I = received more than 5 years life on the last battery.  I maintain = the Legacy batteries on charge as well with a different make. =   

But testing is a different story and = maintainers can't guarantee capacity.    Load testing is the = only way to determine some faults. My batteries failed under load in the = Legacy but not on the ground.  When I pulled gear up everything = died including my Avidynes.   It took a lot of investigation and = help with B&C before we finally tracked it to a problem with the = Odyssey and they were replaced, I think they were 2-3 years old. =  The starting amperage for the hydraulic pump caused the battery to = fail under load.  My point was that for someone like Bob who wanted = to know his capacity, that test will give him a number and a trend each = year.  But since you mention the discharge issue I have calculated = some figures and I am open to corrections and comments of = course.

Assuming the PC925 discussed earlier, = the 10-hour discharge rate capacity is 27AH (2.7a for 10 hours).   = The 20 hour capacity is almost identical at 28AH.  The reserve = capacity is 52 minutes at 25A discharge rate so you have two bookends to = use.

If an owner wanted to discharge at 25A and = got 80% or more of the 52 minutes before voltage dropped to 10,5v then I = would suggest that battery is good.

If the test = was performed at a more conservative C10 rate (2.7A) then the battery = would have to stay above 10v for at least 8 hours (80% of 10 = hours).

Since Odyssey provides those high and = low amperage benchmarks I believe you can determine remaining capacity = using a wide range of rates and keep those batteries at long as they = perform.

Paul
On = 2010-06-21, at 6:39 PM, Chris Zavatson wrote:

Paul,
Changing the = discharge rate during a capacity check will alter the results  = Going higher in current will yield less capacity while using less = current will produce a higher capacity.  The battery has internal = resistance that also uses up power (turns into heat) during the = discharge test.  This loss is roughly a squared function of = the current, therefore changing the discharge current will alter the = results.  
 
I highly recommend keeping batteries on a maintainer = while not in use.  Once I started using these, my batteries = (Concorde 25XC) would retain over 90% capacity even after five = years of use.   I can now replace them based on calendar = time instead of performance.
 
Chris Zavatson
360std
www.N91CZ.com   

 paul = miller <paul@tbm700.com>
To: lml@lancaironline.net
Sent: Mon, June 21, 2010 5:20:51 = AM
Subject: [LML] Re: Odyssey batteries = with very limited warranties

To avoid tossing a good = battery you can do a test similar to that used on our Concorde = batteries.    Take the amp-hour rating (C1) and draw a load = and measure the amps and time down to the threshold of 10v or 20v = depending on the battery.   If we can get 80% of the rated A-H = capacity we keep it.  But, we use a normal discharge rate in the = airplane, not a full draw at C1 as I think that is unnecessary.   = So, maybe something like 20% of C1 discharging through some lights for = example or a rate that duplicates a discharge rate in the airplane in = your worst condition so that it will show up any faults under load. =   Take a measurement every X minutes and get your capacity. =  I'd do it on the bench out of the airplane and track the capacity = between annuals.

We previously tossed these expensive batteries based = on calendar life but we can now leave them on condition using these = tests.

Paul
On 2010-06-19, at 3:01 PM, = Robert R Pastusek wrote:

Robert Simon = wrote:
 
Just had two = of my four Odyssey PC680 batteries crap out after 2 years of service = although an identical set on the other buss are fine=85
Robert,
I have a = similar setup in my IV-P and had planned to replace two of the four = batteries every two years, expecting them to last for four years=85but I = never looked at the expected/advertised life; I was just following a = practice used for lead/acid batteries. Two of my batteries are coming up = on two years old; the other pair are coming up on four years, and I=92d = planned to replace them during the condition inspection next month. = I=92d  appreciate your thoughts/experience on = this.
Thanks,
Bob




= --Apple-Mail-149-395702013--