Diamond DA 40 Flight Manual page 268

Airplane
Description
7.11.1 GENERAL
The DA 40 has 28 Volt DC system, which can be sub-divided into:
- Power generation
- Storage
- Distribution
- Consumers
Power Generation
The 70 Ampère alternator (generator) is mounted on the front of the engine. It is driven
by a V-belt, and charges the battery. In the event of alternator failure, the battery provides
the system with electrical energy. Given the provision of these two independent sources
of electrical power, the complete failure of the electrical system is extremely unlikely.
Storage
Power is stored in a lead-acid battery which is mounted in the right-hand side of the engine
compartment. It has a capacity of 10 Ampère-hour or more, depending on the battery
type. The battery is connected to the airplane electrical system via the main (70 Ampère)
circuit breaker.
In addition, a non-rechargeable dry battery or a lithium battery pack is installed in the IFR
model as a further source of power for the attitude gyro (artificial horizon) and the flood
light. When the emergency switch is set to ON, these two systems are supplied with power
for 1 hour and 30 minutes, independent of all other electrical consumers.
Distribution
Electrical power is distributed via the main bus and, if installed, the essential bus.
Page 7 - 42 Rev. 8 01-Dec-2010
DA 40 AFM
Doc. # 6.01.01-E