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From YouTube: Battery Matching KA2UPW
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B
So
my
name
is
douglas
kilo,
alpha
2,
uniform
pop
of
whiskey,
and
quite
some
time
ago
I
got
interested
in
batteries
because
a
lot
of
the
satellites
that
amateurs
launch,
the
electronics
are
still
working,
but
the
batteries
die
and
that's
the
end
of
the
mission
when
the
batteries
die.
They're
they're
not
designed
to
run
completely
off
the
solar
panels.
B
Yes,
the
u11
satellite
that
the
university
of
surrey
launched
as
well
as
the
microsofts
had
some
very
long-lived
battery
packs.
The
u11
of
cells
was
matched
by
larry
kaser
and
a
team
that
he
led.
B
They
had
a
matching
process
that
they
went
through
and
the
batteries
on
u11
lasted
for
a
really
long
time
and
one
of
the
questions
was
well.
Why
did
the
u11
batteries
last
so
long?
And
I
think
part
of
it
is
that
when
they
started
they
started
with
a
good
set
of
probably
new,
but
certainly
the
high
quality
high
capacity
commercial
nicad
cells.
B
They
then
had
a
matching
process
that
they
went
through
where
they
eliminated
suspect
cells
and
they
also
matched
the
capacity
of
the
cells
to
each
other
and
picked
a
bunch
that
were
the
best
match
and
they
know
in
a
couple
of
places.
It's
not
the
best
cells.
It's
the
best
match
to
each
other
cells,
part
of
their
elimination
process
was
they
did
things
like
they
x-rayed
the
cells,
they
put
them
under
a
very
high
discharge
and
anytime.
They
saw
something
that
they
didn't
like,
or
that
didn't
look
like
the
rest
of
them.
B
In
addition,
the
time
between
when
they
knew
they
had
a
launch
opportunity
and
the
time
they
had
to
deliver
themselves
and
when
u11
was
actually
launched,
was
a
very
short
campaign.
It's
only
several
months
that
they
had
and
a
side
effect
of
this
is
the
cells
that
they
picked.
B
B
In
addition,
the
orbit
of
uo
11
has
long
periods
of
time
when
the
satellite
is
in
full
sun.
There's
no
eclipse
so
there'll
be
long
periods
of
time
when
the
batteries
are
not
being
heavily
taxed.
If
at
all
and
that'll
increase
the
lifespan,
because
they're
just
sitting
there
charged
with
very
little
demand
put
on
them.
B
A
B
A07
is
now
back
in
service,
but
it
looks
like
just
the
batteries
failed
shorted,
so
the
power
from
the
solar
panels
gets
to
the
electronics,
but
the
batteries
don't
have
any
capacity
to
hold
any
charge.
So
as
soon
as
the
satellite
is
no
longer
illuminated
by
the
sun,
everything's
going
to
turn
off
we're
just
lucky
that
that
worked
out
the
way
it
did.
If
it
failed
to
open,
then
the
satellite
wouldn't
be
working
but
it'd
be
better
if
we
had
a
long
life
battery
pack.
B
B
He
talks
about
some
of
his
early
results.
He
has
a
nicad
hypothesis
that
he
wrote
up
and
again
it's
the
set
of
best
matched
to
each
other
cells,
not
the
best
cells,
but
exactly
what
they
did
and
how
they
did.
It
is
not
outlined
in
the
any
step-by-step
procedure
that
was
published
anywhere,
at
least
as
far
as
I
know,.
A
B
There's
bits
and
pieces
that
larry
wrote
on
amsa
bb
over
the
years.
If
you
go
search
through
the
archives
for
all
his
postings,
you
can
find
stuff
that
he
wrote
and
I
did
track
down
one
member
of
the
the
team
who
actually
did
a
lot
of
the
hands-on
work
and
it
doesn't
look
like
there
was
anything
special
magic
or
higher
order,
mathematics
that
they
did
to
match
the
cells.
They
did
have
a
process
that
they
followed
to
measure
the
capacity
of
each
cell,
and
but
they
didn't
do
any.
B
A
Okay,
so
in
recreating
all
of
the
these
tests
with
modern
equipment,
we
we
actually
have
some
significant
advantages
in
that
we
can
use.
A
You
know
automated
testing
fixtures
to
test
the
the
capacities
and
the
to
get
the
charge
and
disk
discharge
curves,
and
we
we
also
have
a
lot
of
inexpensive
and
powerful
mathematic
programming
to
you
know
you
can
either
use
a
python
script
or
even
you
can
use
matlab
you
can
use.
You
know
a
spreadsheet.
A
I
mean
we,
we
now
have
you
know
a
way
to
to
recreate
to
test
and
to
to
publish
all
of
this
work.
You
know
that
is
a
lot
easier
than
than
plotting
them
out,
maybe
on
a
transparency
and
and
then
picking
out
the
best
ones
by
by
looking
at
them
so
in.
In
order
to
to
recreate
this,
it's
sort
of
like
the
first
step
to
maybe
moving
on
to
other
battery
chemistries
more
the
ones
that
are
currently
being
looked
out
for
use
in
space.
A
Although
the
the
matching
requirements
of
lithium-ion
are
different
than
the
matching
requirements
of
nicad,
there
are
still
an
awful
lot
of
nicads
available
and
as
an
inexpensive
and
well-studied
thing
to
to
put
in
space,
it's
it's
really
not
a
bad
choice
is,
is
your
hope
that
that
missions
coming
up
that
are
experimental
or
amateur
might
might
want
to
use
some
of
these
packs
that
have
well-matched
cells.
B
The
ones
launched
from
the
iss,
the
the
the
orbit
is
going
to
put
you
in
sunlight
in
the
clips,
with
with
a
rather
large
eclipse
on
every
orbit,
but
also
the
lifespan,
just
from
from
the
the
height
of
the
orbit
stuff
launched
from
the
iss,
is
not
going
to
last
very
long
to
begin
with,
so
to
to
validate
that
we
actually
have
a
long-lived
battery
pack.
We
don't
want
something
that
comes
out
of
the
iss.
B
But
some
other
commentary
I
found
suggests
that
it's
more
commentary
about
contaminants
that
might
be
in
the
electrolyte.
If
they
didn't,
you
know
wash
out
the
front
end
loader
sufficiently
after
they
used
it
for
something
other
than
electrolyte
ingredients,
so
there
that
there
might
be
some
impurities
in
there.
B
But
I
I
don't
know
because
I
don't
know
the
company
that
made
the
batteries
and
the
x-raying
that
they
did.
Larry
only
notes
that
he
saw
some
things
that
he
didn't
like
and
eliminated
those
cells
from
consideration.
But
he
doesn't
say
what
he
saw
so
it
may
have
been
contaminants
or
it
may
have
been
some
of
the
internal
welds
that
either
didn't
look
good
or
just
didn't.
Look
like
all
of
the
other
cells
that
they
x-rayed,
and
so
they
were
eliminated.
B
B
So
once
we
get
to
something
that
works
and
we've
verified
that
we
have
good
procedure,
we'd
like
to
write
it
up,
get
published,
get
feedback,
get
other
people
to
also
reproduce
our
results
and
perhaps
suggest
improvements
and
then
eventually
expand
it
out
to
other
battery
technologies.
For
starters
that
were
just
looking
at
the
nicads.
A
Something
that
I
found
to
be
surprising
was
how
how
little
in
terms
of
like
academic
work
or
guidelines,
how
how
little
about
cell
matching
is,
is
easily
accessible.
I
found
a
paper
from
years
ago:
that's
a
it's
quite
a
good
one
about
about
cell
matching
from
the
navy,
and
it
was
very
good
practical
knowledge.
It
didn't
rely
on
on
fancy
mathematics.
A
This
was
just
curve,
fitting
least
mean
squares
types
of
calculations
and
not
too
many
points
either.
You
know
it
could
be
done
in
a
lab
with
relatively
simple
equipment
by
somebody
who
was
just
checking
every
now
and
then
to
get
to
get
the
points
and
then
a
more
recent
paper
about
cell
matching
that
looked
more
into
environmental
cell
matching,
so
so
the
performance
of
under
temperature.
So
you
would,
you
would
pick
the
cells
that
that
could
perform
in
the
temperature
range
you
wanted
to.
A
This
was
for
an
industrial
application,
so
the
temperature
range
was
quite
demanding,
and
that
was
pretty
much
it.
So
I
was
I
was
intrigued
by
by
the
to
me.
A
The
non-intuitive
part
of
this
was
that
you
don't
want
the
best
cells
that
you
wouldn't
just
pick
the
best
cells
out
of
a
group,
because
they
may
not
work
together
very
well
as
a
battery,
and
you
know
it
might
be
worth
describing
exactly
what
happens
with
batteries
when
you,
when
you
do
that,
when
you
pick
the
very
best
and
put
them
together
to
make
those
put
to.
B
Well,
one
if
they're
not
well
matched
one
or
more
of
the
cells
will
be
discharged
before
the
others
and
potentially
gets
discharged
to
a
greater
amount
than
the
others.
And
when
this
happens
repeatedly
that
battery
or
those
two
batteries
become
more
likely
to
either
fail
or
potentially
reverse
before
the
others.
A
C
B
B
So
when
that
one
fails,
then
that
one
potentially
can't
hold
a
charge
anymore,
and
so
it
no
longer
contributes
voltage
and
current
to
whatever
the
load
is
and
if
they're
well
matched.
Then
they
should
all
charge
up
together
as
a
group,
and
they
should
all
discharge
together,
as
a
group
and
voltages
should
be
similar
as
they
charge
and
discharge
so
that
there
isn't
any
one.
A
Okay,
so
you
can
have
a
case
where
you
have
an
all-star
team,
but
the
the
difference
between
those
batteries
is
pretty
can
be
pretty
large
but
percentage-wise
and
that
that
pack
might
fail
well
before
one.
It
was
middle
of
the
range
you
know
in
terms
of
capacity,
but
they
all
work
together
as
a
good
team.
You
know
the
difference
between
the
the
batteries.
Wasn't
that
that
much
and
that.
B
B
Yeah
we're
going
for
long
life,
not
best
performance,
and
what
what
larry
and
his
team
noted
in
several
places
is
when
you're
doing
the
matching
you
want
the
cells
that
are
best
matched
to
each
other,
not
the
best
cells
that
you
have.
I
think
u11
holds
the
records
for
the
largest
number
of
charge
discharge
cycles
and
most
orbits
to
still
have
a
functioning
battery
pack.
What
we
don't
want
is
the
the
battery
pack
to
fail
after
a
couple
of
years
and
the
rest
of
the
electronics
are
all
still
good.
Now.
B
If
we
got
ejected
out
of
the
the
iss,
then
we
only
need
to
last,
for
you
know,
maybe
a
couple
of
years
before
we
re-enter
anyway,
but
if
we
get
into
a
higher
orbit
or
something
more
sun
synchronous,
then
we
want
the
battery
pack
to
last
as
long
as
the
electronics,
if
not
longer.
Yes,
this
is
dk3wm's
loom
program
and
you
can
see
from
this
one.
B
On
your
average
day,
the
iss
spends
a
lot
of
time
in
eclipse
now
there's
a
little
snippet
there,
where
it's
it's
in
full
sun,
maybe
for
a
couple
of
days,
but
most
of
the
days
you're
looking
at
15,
16
orbits
and
there's
a
good
chunk,
that's
in
sunlight,
but
there's
also
a
good
chunk.
That's
an
eclipse.
A
B
A
Okay,
that
that
puts
it
into
a
visual
format
that
is
pretty
pretty
clear,
easy
to
see.
You
can
also
see
it
changes
throughout
the
year.
B
B
B
We
have
to
go
look
at
the
telemetry
and
and
see,
but
my
guess
is
that
when
you're
in
full
sun
you're
not
taxing
the
batteries,
much
if
at
all,
you're
either
running
off
the
solar
panels
or
minimally
using
the
the
batteries.
While
you
run
some
experiments
and
they'll
get
charged
right
back
up
again
because
you're
in
full
sun.
A
B
Anything
that
you
see
on
a
particular
cell
that
doesn't
look
like
what
all
the
other
cells
look
like.
It
doesn't
matter
what
it
is
if
it's
impurities
in
the
electrolyte
or
if
it's
the
the
welds
internal
to
the
cell,
don't
look
like
the
rest
of
the
cells,
whatever
it
is
set
that
cell
aside,
because
if
you
didn't
eliminate
the
bad
ones,
you
wouldn't
know
just
from
matching
the
capacities
that
this
one
had
a
like
a
bad
internal
weld
or
had
some
contaminants
or
something.
A
A
That
makes
it
a
lot
easier
to
to
say:
okay,
you
know
group
them
or
put
a
visualization,
and
we
should
see
a
large
number
of
cells
that
all
are
very
similar
out
to
some
outliers,
depending
on
what
axis
you're
looking
at.
If
we're
just
looking
at
capacity,
we
will
see
that
we'll
see
a
distribution
of
capacities
if
we're
looking
at
at
matching
curves
to
each
other.
It
gets
a
little
more
complicated,
but
we
will
see
some
clusters
of
curves
that
are
very,
very
close
to
each
other.
A
We
do
have
temperature
probe
that
that
goes
along
with
the
voltage
and
current
measurements.
So
if
there
is
any
misbehaving
battery
with
respect
to
temperature,
then
those
those
come
out
as
well,
you
know
yeah
set
on
the
side.
You
know
so
there's
a
couple
of
different
things
to
look
at
and
all
of
this
it
will
be
available.
A
The
as
as
the
batteries
are
being
measured
in
the
remote
lab
remote
lab
west
at
open
research
institute,
then
each
curve
is
put
into
the
repository,
so
the
raw
data
is
available
for
anybody
to
look
at
and
over
time.
The
measurements
that
we're
talking
about
making
will
also
be
in
the
repository.
A
So
there's
there's
multiple
ways
you
can.
You
can
look
at
the
different
sets
of
data?
If
there's
something
that
we're
not
doing,
then,
then
it
can
be
either
suggested
or
or
you
can
go
ahead
and
do
it
then
add
it
to
the
repository
as
well,
and
so
the
the
links
to
that
are
I'm
going
to
I'll
put
those
in
on
the
screen.
C
D
Yeah
just
used
some
battery
carriers
and
hooked
up
some
anodes.
D
I
am
labeling
each
one
of
these
batteries
so
that
when
we
have
data
it
matches
what
number
we
sign
in.
So
this
is
two
and
four
we're
redoing
two
and
doing
four
here.
Okay,
so
I'm
gonna
go
here
and
set
up
each
run,
looks
like
they've
finished.
D
D
Get
some
tape
and
through.
B
D
D
We
are
good
to
go
so
we
go
over
to
our
program
here.
Then
we
just
check
between
these.
You
can
see
the
starting
voltages
one's
lower
than
the
other,
because
the
second
one
is
already
done.
One
of
these
runs
and
we'll
go
ahead
and
get
started.
D
Diesel
calibrate,
run
a
quick
charge,
cycle
equalize
and
then
discharge
and
then
recharge
and
equalize
again.
C
How
long
does
it
take
usually.
C
A
A
And
so
what
what
you
can
see
is
voltage
coming
up
to
charge,
so
you
can
see
a
lot
of
inrush
current
going
going
into
the
cell
and
then
this
long
right
so
that'd
be
right
here.
A
Long
flat
yeah,
it's
called
the
equalization
charge,
so
you
can
see
it
come
up
and
then
and
then
this
the
voltage
is
holding
steady.
So.
A
Discharge
so
it's
a
discharge
set
part
of
the
of
the
curve
and
you
can
see
that.
A
C
D
D
I
were
to
put
my
hand
on
the
mount
here.
I
can
see
that
you
can
feel
it
a
little
bit
warmer
than
the
other
cell
at
the
moment.
D
D
Yeah,
these
readouts
give
us
some
basic
info,
the
same
stuff,
that's
charted
over
here,
but
the
the
action
times.
If
you
were
to
look
here
and
compare
along
the
graph
here,
you
can
see
we're
currently
in
the
discharge
portion
of
the
cycle
and
if
you
were
to
look
back
here,
it
reports
we're
trying
to
hit
peak
charge
and
then
it
equalizes
and
yeah.
It's
just
about
that.
C
A
This
gets
saved
into
a
file
and
put
on
the
github
repository,
and
so
each
of
these
data
sets
are
available
to
anybody
through
the
the
repository.
D
Now,
when
the
run's
finished,
you
basically
repeat
this
process.
We
have
a
finished
run
here,
the
next
day,
so
go
ahead
and
exit,
and
you
just
pull
the
batteries
off
the
mount,
get
them
sorted
with
the
next
set,
and
once
you
have
a
good
batch
of
data,
you
can
go
to
the
file
viewer
and
then
take
your
uba
files
and
let's
go
with
37
here
and
file
and
then
write
data,
and
what
this
will
give.
D
You
is
a
csv
file
and
from
there
it'll
report
to
documents
vent
con
reports
and
logs,
you
can
find
it
there
and
once
you
have
a
good
batch,
you
can
upload
it
to
the
repository.
D
Now,
when
I
have
a
good
batch
of
these
around
10
or
so
just
go
ahead
and
upload
it
to
the
repository,
sometimes
I
use
discord
to
get
the
files
over,
but
sometimes
I
can
upload
it
from
this
terminal
as
well,
and
at
that
point
you
just
keep
doing,
runs,
keep
doing
file
transfers
until
you're
all
out
of
batteries.
If
you
were
looking
at
the
uva
console
earlier,
you
might
have
noticed
we
had
a
failure.
D
I
think
it
was
for
this
cell
and
whenever
that
happens,
we
go
ahead
and
retest
them
on
the
mount.
The
working
theory
is
that
the
batteries
might
need
to
be
conditioned.
Whenever
we
encounter
a
failure
for
capacitance.
We
go
ahead
and
swap
the
cell
on
the
mount
and
from
there
it
usually
tends
to
play
nice,
but
we've
had
a
few
that
we
still
need
to
retest.
D
You
can
see
that
the
next
run
is
set
up
here.
This
would
be
the
40s
yeah
39
completes
that
group,
so
we're
starting
another
run
here
and
once
we
have
about
10
grab
the
csvs
like
earlier
and
go
ahead
and
upload
those.
A
This
is
some
really
good
work
and
it's
it's
really
fun
to
be
able
to
kind
of
bring
it
out
and
prove
it
out
and
then
publish
it
to
show
what
a
quality
competent
job
amateurs
did
on
this
in
this,
for
the
small
sets
for
u11
high
quality
state,
high
standards
and
high
performance
that
has
been
achieved
in
in
the
past,
and
that
will
continue
to
do
in
the
present
and
in
the
future
of
the
amateur
satellite
service.
A
Yeah
yeah,
that
would
be,
that
would
be
ideal
or
if,
if
anyone
out
there
knows
of
a
of
a
challenging
terrestrial
mission
like
a
buoy
or
I'm
not
going
to
say
balloon,
because
these
batteries
are
kind
of
heavy,
but
something
like
that,
a
tourist,
a
long
long-lived
terrestrial
mission
that
has
to
has
to
last
for
a
while
without
any
intervention,
then
get
in
touch.
We
we
may
have
the
pack
for.