Monaco 2002 Diplomat, Service Manual

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Electrical Systems - House
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D I P L O M A T
8 • 2 2 8
feeding the pump as fast as needed the pressure will eventually drop. This anal-
ogy 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.
The working range of a deep cycle battery is between 50 and 100% state of
charge (SOC). Deep cycle batteries should not be cycled below 50% state of
charge. Discharging a deep cycle battery below 50% state of charge shortens the
life of the battery. Deep cycle batteries use an amp hour rating which is usually
calculated over a 20 hour discharge interval. For example: A deep cycle battery
with a rated capacity of 100 Ahrs. is designed to release current at the rate of
5Amps per hour. Multiply a 5 Amp load over a 20 hour discharge period equals
the rated 100 Ahr. capacity. These discharge figures are calculated with the bat-
tery starting at 100% state of charge with the battery at 80º F when the dis-
charge cycle begins. However, increasing the discharge load applied to the bat-
tery from five amps to ten amps on a 100 Ahr battery does not yield 10 hours of
discharge time. This is due to the internal reactions which occur when a battery
is discharging. Actual discharge time for a 10 Amp load may be closer to eight
hours of discharge time. Increasing the load applied to the battery to 20 Amps
will not yield five hours discharge time but may be less than three hours. It
might be understood as a point of diminishing return.
Battery Charge Time
& Consumption Rate