LiPo Batteries in Gliders

In article ,
Eric Greenwell wrote:

GM wrote:
The prices have dropped to a very affordable level; so have the
chargers/balancers. The weight savings are considerable. My 12V/7.5Ah
standard sealed gel-cell weighs 2.35kg (5.17lbs) and it lasts a few
days. I found two 7.4V/5.0Ah units on e-bay that weigh in at 0.3kg
each (0.6kg or 1.32 lbs in total)
Why do you wish to save 1.75 kg/3.85 pounds? That small amount can not
possibly affect your glider's performance. I mean, my drinking water
weighs about 6 pounds.

Libelle drivers understand very well why saving weight is important.
Gliders often get heavier with age. Our venerable Libelles have
accumulated repairs, more instruments, etc. so that we are often above
the (unrealistically low) "official" weight, thus incurring a handicap
penalty in sports/club class. Not really much of a competitiveness
issue, but when one nudges the "all up" weight limit, contest officials
get all serious and make unsettling noises.