On Feb 24, 10:50*pm, GM wrote:
Hi,

it's still winter with lousy weather in the northern hemisphere, so it
is time to warm up an old discussion. I searched the forum for threads
reg. Lithium-Polymer Batteries and there have been none for a while.
Here are the questions:
- Does anyone have real life experience with LiPo's in a glider? (real
gliders, that is - not models)
- Can I combine two 7.4V packs in series to get a 14.8V unit or is
there a risk with that?
- How would one charge a combo like this? Each unit by itself and then
hook them together or with one charger while hooked together?

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)

Any input is welcome.

Uli Neumann
'GM'

Uli, call me. I just bought a 12V 10 Ah Lithium Phosphate battery
from K2. It comes in the same physical package as a 7 Ah 12 V SLA
battery, it much lighter than a normal SLA battery and my preliminary
tests indicates it has a useful capacity almost equal to a 12 Ah SLA
battery. It has a circuit board in it to balance the individual cell
charge while charging, and it includes over discharge protection as
well. This looks like a safe alternative to the SLA batteries and if
you factor in the increased number of cycles available, its going to
be cheaper in the long run.

SF