Bill,

I strongly discourage you from considering lithium batteries for use in
your glider. A lithium fire, once started, is virtually impossible to
put out. Putting water on burning lithium actually feeds the fire (it
generates hydrogen). I read about one incident involving a laptop
battery that caught fi he ended up throwing the entire laptop with
burning battery into a snow bank, which only intensified the fire.
Improper charging of lithium batteries are the primary, but not only,
cause of these fires. An enlightening report on the subject is at:

http://www.ntsb.gov/publictn/2005/HZB0501.pdf

Tom Seim
Richland, WA

Bill Daniels wrote:
Lithium Ion rechargeables seem to have recently seen a 50% or so price drop.
A 4-cell, 14.8V, 8AH with charger and mounting plate can be had for $169.99
(USD). These are basically long endurance laptop batteries.

This is still too much for me given that a SLA with the same capacity is
around $25 but the downward price trend is hopeful. Someone contemplating a
transponder, electric T&B and other juice hungry gadgets in a $100,000+
glider might see Li-Ion as a possibility now.

Beyond price, my concern is voltage. 4-cell Li-Ion packs produce 14.8V and
a detail in the spec sheet admits that a new, fully charged pack might
produce 16.2V into a high resistance load. My avionics manuals say 16V max.
Is that 0.2V overvoltage likely to be a problem?

Bill Daniels