SMA SI 4548-US - Manual (Page 53)

SMA America, LLC 6 Electrical Connection
Operating Manual SI4548-6048-US-BE-en-20 53
6.4.2 Connecting the Data Cable of the Lithium-Ion Batteries
Requirements:
The total length of the communication bus must not exceed 98 ft (30 m). Keep in mind that the
communication bus possibly connects several nodes such as additional Sunny Island inverters.
The data cable must be a CAT5 cable with RJ45 plugs.
1. Plug the data cable into a free pin connector ComSync on the Sunny Island.
2. Connect the other end of the data cable to the battery management of the lithium-ion battery
(see battery manufacturer documentation).
3. Ensure that the communication bus is closed at each end, e.g. with a terminator.
6.4.3 Battery Temperature Sensor
The battery temperature sensor measures the temperature of the connected battery. For lead-acid
batteries, this is necessary since the optimum charging voltage for a battery strongly depends on the
temperature (see Section 13.5 "Charge Control", page 110). For lithium-ion batteries, the external
battery management transfers the battery temperature to the Sunny Island and thus replaces the
battery temperature sensor.
The battery temperature sensor must be connected for the operation of the Sunny Island (included in
the scope of delivery). In case of a fault (short circuit, cable break), the Sunny Island operates in a
safe setting, which over time leads to deep discharge of the battery. A warning indicating that the
defective battery temperature sensor should be replaced immediately is displayed.
Destruction of the battery through deep discharge as a result of the installation of an
unsuitable battery temperature sensor
• Only use the battery temperature sensor included in the scope of delivery.
• Do not drill holes into the battery to install the battery temperature sensor.