President's Perspective-2007/04

here do you store and charge
your Lithium batteries? Have
you given much thought to that?
Unfortunately, there has been
another fire that took an AMA member’s
house, but luckily it did not result in any
injuries or loss of life.
This time the situation concerns me
more than past instances. In this case the
modeler reportedly had taken the battery
off of charge and placed it on the bench
while he went into the house for dinner.
That is right—the battery was not
connected to the charger when it burst into
flames and set the wooden bench and
surrounding material on fire.
The fire consumed the entire house but
the modeler and his family were able to
get out, safely.
This incident, which has not been fully
investigated as I am writing this, brings up a
new, potential problem and it is one from
which we can all learn. Before this episode,
I had never heard of a fire started by a
battery that had been taken off the charger
unless it had been visibly swollen during the
charging process or had physical damage.
From the report I received, this battery
did not show any damage or swelling
when it was removed from the charger so
it should have created a miniscule threat
for fire.
Did the modeler look the battery over
carefully? Had it started swelling but it
was not apparent? Was it excessively hot?
What charger and charging rate were
used? Was the pack balanced during the
charging process?
President’s Perspective
AMA President Dave Brown
W We still have many questions at this
point, but that does not mean that we should
ignore the incident.
I have gotten involved in electric helicopter
flying, and in the course of this have had an
opportunity to see various methods of
handling batteries during charging and
storage. I’ve seen the whole spectrum of
care being given to these processes. I’ve
seen batteries thrown onto paper sacks,
laying loose in toolboxes, secured in
fireproof vaults, in a product called the
LipoSack, and in a Battery Bunker charging
container.
During transport, charging, and storage,
is there a correct way to handle these
batteries? No, there is not, but there are
“smart” ways and “not-so-smart” ways.
Fortunately, fires with Lithium batteries
are still somewhat rare, but when they
happen, they are serious. The rarity of an
occurrence has a tendency to lull us into the
habit of using bad practices in handling
these batteries. If you use rechargeable
Lithium batteries of any type, it is in your
best interest to respect the dangers and to
handle them with appropriate care.
Personally, I prefer to store and transport
them in a fireproof container. I use a
LipoSack for this purpose, and I like to
charge them in this sack or in a Battery
Bunker.
Chargers are another potential source of
difficulty and many of them charge through
the two-wire output plug, ignoring the
balance (node) connector which is there to
monitor the status of each cell in the pack. I
If you use rechargeable Lithium batteries of any type
... handle them with appropriate care.
would not use a charger without some form
of balancer.
A large number of the fires that have
been reported to me involve chargers that do
not have any active balancing component. It
does not matter if this feature is a part of the
charger itself or as a separate component
that plugs in, but the continued charging of
Lithium batteries without a balancing system
can lead to trouble.
I’m amazed when I hear from people in
person and on Web sites that they are going
to buy a balancer when they can afford one,
but they keep charging and using the
batteries in the meantime. This can be a
dangerous game of roulette and it’s putting
your property and your family in jeopardy.
Please do not do this! Imbalance in the cells
in the battery is the most likely cause of
swelling in a cell and an ensuing fire.
I’m also astounded when I hear or read
about people who are still using batteries
that are visibly swollen. I even came across
an advertisement on eBay in which the items
being sold were Lithium batteries that were
“only slightly swollen.” I hope you were not
the person who bought them! MA
Til next month …
Dave Brown
AMA president
[email protected]