Volvo IPS650, Installation Manual

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Batteries
Battery terminology
Capacity
Capacity is measured in ampere hours (Ah). Start bat-
tery capacity (Ah) is normally specified as the battery
20-hour capacity, i.e. the battery will be discharged by
a constant current over 20 hours until it reaches a final
voltage of 1.75 V per cell. For example: If a battery is
able to produce 3 A over 20 hours, its capacity is 60
Ah.
The ampere value at cold start (CCA) measures bat-
tery start capacity. The SAE (Society of Automotive
Engineers) specifies the following test: A battery at a
temperature of -18 °C (0 °F) must be able to provide
current equivalent to the ampere value during a 30-
second cold start with a constant voltage level above
1.2 V per cell or 7.2 V for a 12 V battery. There are
other CCA tests defined by DIN, JIS, and ETN, etc.
These tests give other CCA values than the SAE test.
Battery capacity is influenced by temperature. Battery
capacity is specified at +20 °C (68 °F). Cold signifi-
cantly reduces a battery's ability to release energy. The
following table shows capacity differences at +20 °C
(68 °F) and -18 °C (0 °F).
Temperature +20 °C (68 °F) -18 °C (0 °F)
Capacity 100 %
70 %
40 % 50 %
35 %
25 %
If the boat has several batteries, the following connec-
tion method must be used:
Series connection:
When two 12 V batteries are connected in series, boat
system voltage will be 24 V.
IMPORTANT!
Always check boat system voltage before connection.
Engines may be in 12 V or 24 V configurations.
The batteries must be identical in respect of:
• Type
• Voltage
•
Capacity
• Age
IMPORTANT!
Batteries may not be subjected to different loads
(equipment must subject both batteries to load –
not
just one ). A small power consumer, such as a radio
connected to only one battery can quickly destroy both
batteries.
Installation, Electrical System
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