Originally posted on the SARFY list by Shelly Tayler
Subject: AMA Safety Committee Announcement - April 23rd, 2004 - Lithium
Battery Hazard
Date: Sun, 25 Apr 2004 09:48:23 -0500
From: Safety Committee: safety@modelaircraft.org
EMERGENCY SAFETY ALERT
Lithium Battery Fires
Lithium batteries are becoming very popular for powering the control and
power systems in our models. This is true because of their very high
energy density (amp-hrs/wt. ratio) compared to NiCads or other
batteries. With high energy comes increased risk in their use. The,
principal, risk is FIRE which can result from improper charging, crash
damage, or shorting the batteries. All vendors of these batteries warn
their customers of this danger and recommend extreme caution in their
use. In spite of this many fires have occurred as a result of the use of
Lithium Polymer batteries, resulting in loss of models, automobiles, and
other property. Homes and garages and workshops have also burned. A
lithium battery fire is very hot (several thousand degrees) and is an
excellent initiator for ancillary (resulting) fires. Fire occurs due to
contact between Lithium and oxygen in the air. It does not need any
other source of ignition, or fuel to start, and burns almost explosively.
These batteries must be used in a manner that precludes ancillary fire.
The following is recommended:
1. Store, and charge, in a fireproof container; never in your model.
2. Charge in a protected area devoid of combustibles. Always stand
watch over the charging process. Never leave the charging process
unattended.
3. In the event of damage from crashes, etc, carefully remove to a
safe place for at least a half hour to observe. Physically damaged
cells could erupt into flame, and, after sufficient time to ensure
safety, should be discarded in accordance with the instructions
which came with the batteries. Never attempt to charge a cell with
physical damage, regardless of how slight.
4. Always use chargers designed for the specific purpose, preferably
having a fixed setting for your particular pack. Many fires occur
in using selectable/adjustable chargers improperly set. Never
attempt to charge Lithium cells with a charger which is not,
specifically, designed for charging Lithium cells. Never use
chargers designed for Nickel Cadmium batteries.
5. Use charging systems that monitor and control the charge state of
each cell in the pack. Unbalanced cells can lead to disaster if it
permits overcharge of a single cell in the pack. If the batteries
show any sign of swelling, discontinue charging, and remove them
to a safe place outside as they could erupt into flames.
6. Most important: NEVER PLUG IN A BATTERY AND LEAVE IT TO CHARGE
UNATTENDED OVERNIGHT. Serious fires have resulted from this practice.
7. Do not attempt to make your own battery packs from individual cells.
These batteries CANNOT be handled and charged casually such as has been
the practice for years with other types of batteries. The consequence of
this practice can be very serious resulting in major property damage
and/ or personal harm
Safety Committee
Academy of Model Aeronautics
5161 E Memorial Drive
Muncie, IN 47302