When I wanted to install LiFeP04 batteries in my 27, I asked the factory
and Uli Kramer's response was as follows:

"in principle we have approved these batteries with TN 2-2008 (attached):

“3. Parts not belonging to the Minimum Equipment

• Electric equipment and its aerials may neither in themselves nor by
their mode of operation
or by their effect upon the operating characteristics of the sailplane and
its equipment
constitute a hazard to safe operation.
Every electric equipment has to be checked for reciprocal influence by
systematically
turning off and on and operating all other instruments.
The equipment and its control and monitoring devices must be arranged so as
to be easily
controllable. Their installation must be such that they are sufficiently
ventilated to prevent
overheating.“


So a battery is also an electric equipment…..

Kind regards

Uli"

TN 2-2008 applies to all Schleicher gliders.

Jim

The ASH26e Maintenance Manual, section 2.8 states that EITHER the YUASA
(or=
similar) or the Sonnenshein Dryfit A212 may be used. Nowhere does it say
O=
NLY a gel cell battery is permissible. Speaking as an electrical
engineer,
=
I consider the Odyssey PC680 to be "similar" to the YUASA in form and
funct=
ion. The LiFePO4 definitely is not and should necessitate a 337 STC for
cer=
tificated gliders like mine, not to say that it can't be done.

Tom