Jones Brothers Cape Fisherman, Руководство пользователя, Страница: 49 / 64

OPERATION
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© Copyright Jones Brothers Marine Manufacturing, Inc. 2008
In the 1 position, battery #1 is only used for cranking and battery #2 runs the accessories.
Both batteries are charged simultaneously - the cranking battery through the positive
battery cable and the accessory battery through the battery isolator charging wire.
In the 2 position, all loads and charging currents are connected to accessories battery #2.
Now it supplies current required by starting and running, and it receives all the charging
current from the engine. The Cranking battery #1 is totally isolated.
In the BOTH position, the two batteries are connected in parallel. This has a number of
implications. Unless the batteries have exactly the same state of charge, the combined
voltage to the two batteries in parallel will sag to a voltage somewhat lower than the highest
battery's terminal voltage. Current from the higher voltage battery will flow into the lower
voltage battery and begin charging it. As long as the state of charge in one battery is higher
than the other, the lower battery is more of a load than a source of power. Eventually, the
batteries will reach an equilibrium, and they will both have the same terminal voltage. At that
point they will both tend to supply current to loads that are attached to them, and they will
both receive charging current furnished by the engine.
It would seem like operating in the BOTH position would be beneficial, but that is not always
the case. Even thought the batteries will eventually rise or fall to the same terminal voltage
when connected together, they will not necessarily become exactly the same. To describe
the situation in the simplest of terms, when two batteries are connected in parallel, they will
probably tend to behave more like the weakest battery of the two than the strongest.
Paralleling the batteries can come in handy in some situations. For example, both batteries
may be discharged to a point where neither alone can provide enough current to crank the
starter motor, but combined in parallel they can turn the engine over.
If one battery is fully charged and the other is totally discharged or damaged, connecting
them in parallel (by using the BOTH position) can cause very high currents to flow between
the batteries. Extreme heat can be generated by the sudden charging of the discharged
battery. Use caution in this situation. It is better to recondition a discharged battery by slowly
re-charging it with an AC-operated battery charger.
The arrangement of the contacts of the typical OFF-1-2-BOTH permits the operation of the
switch in the range of 1-2-BOTH without ever disconnecting the batteries from the load or
the outboard charging circuit. This is important, as it is possible to cause damage to the
charging circuit if the battery is disconnected while the engine is running. By choosing the
path of rotation of the switch, it is possible to change from 1 to 2 without moving through the
OFF position. Note: The Make-Before-Break feature on the switch allows switching
between 1-ALL-2 positions with running engines.