Holiday Neptune 2004, Руководство пользователя

Страница: 304 / 416

When the tank is full it is capable of feeding more “pressure” to the pump inlet
due to gravity, and the pump always has enough water available to maintain its
rated pressure and volume. However, if the water tank gets low the pump will not
have enough water volume coming in to maintain 12 psi at 15 GPM. If the loads
are removed from the pump by closing the valve on the outflow, even with low
pressure in the tank the pump will eventually pressure up to 12 psi. It will just take
it longer to get there. When the valve is opened the pump will sustain 12 psi for a
brief period, but since the tank is no longer feeding the pump as fast as needed the
pressure will eventually drop. This analogy can be restated by replacing the pump
with a battery, pressure with voltage, volume with amps, outflow valve with a
switch, water with electricity and the water tank with the battery electrolyte.
The level of the tank could be thought of as the rate of the reaction occurring in
the electrolyte. When the battery is fully charged the electrolyte has an excess of
reactions taking place to feed the battery terminals. This tapers off with time as the
electrolyte is spent, so maintaining voltage becomes possible. With no loads the
discharged electrolyte will be capable of producing close to the rated voltage, but
only after a period of time has elapsed for enough of a reaction to take place to
bring the voltage back up. Hopefully, this explanation will clarify why a battery
measured at rest can indicate close to its rated voltage but will not run a load.
Calculating Run Times:
Calculating run time figures when operating 120 Volt AC electrical items
with an inverter can be exponential. This is due to battery characteristics. Flow
characteristics of electrons vary with different battery types and chemical
compositions. Deep cycle batteries are generally designed to slowly release a
majority of their charge capacity. Deep cycle batteries are rated in amp hours
(Ahrs) with the discharge occurring over an extended period of time before the
battery is charged. Engine starting batteries are designed to quickly release large
amounts of current for short durations, without depleting battery reserves.
Commercial type batteries bridge the gap of deep cycle and engine batteries.
Commercial batteries release medium amounts of current over a longer period of
time but they are not designed to cycle their charge capacity.
304 • SECTION 8 --- ELECTRICAL SYSTEMS - HOUSE NEPTUNE 2004
Battery Charge Time
& Consumption Rate