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Chris, et al,
I use Battery Tenders (BT) on all SLA batteries if there will be
extended periods of disuse, including the airplane. I have a B&C
battery (may be an Odyssey) from 1998 (before the BC110 reversed the
anode/cathode position) that still powers the start motor on a
generator. My tractor battery (used for mowing and snow removal) has
been maintained for years on a BT when not in use. My motorcycle sits
unused through the winter months - the battery is from 2000) and spends those
cold months on a BT - it still works. I have made use of discarded
B&C batteries all over the place - used for raising my airplane on electric
jacks, used for winching it in, etc. They continue to be usable if
maintained with a BT from time to time. I do not temp fate - the aircraft
battery (B&C) is often replaced every 3 or 4 years depending on how I have
misused it. Pre-flight requires checking both the main battery and the EI
backup battery for VDC levels and trends.
A battery expert (usually an older person) will tell you that this is nuts
- they just haven't experienced a well made SLA battery with pads and
their reliability - if kept charged/maintained. Of course, that's just my
observation.
Grayhawk
In a message dated 6/21/2010 5:39:52 P.M. Central Daylight Time,
chris_zavatson@yahoo.com writes:
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
N91CZ
360std
From: 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:
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…
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…but 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’d planned to replace them
during the condition inspection next month. I’d appreciate your
thoughts/experience on this.
Thanks,
Bob
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