Monarch SE 2004 - Battery Voltage & Current

Monarch SE 2004-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Section 8 Electrical System | 313
7. Overcharging:
Overcharging rapidly converts water to gas and decreases the electrolyte’s
water content as the water evaporates. The electrolyte level drops and
becomes more acid in content. This subjects the plates to a higher concentration
of sulfuric acid and results in early battery failure.
NOTE: Any time more than one or two ounces of distilled water
is added per-cell per-thousand miles, check the motorhome
charging system for overcharging. Prolonged overcharging gener-
ates excessive heat inside the battery, which buckles the plates
and destroys the battery. It is a fact that over 50% of battery
failures are caused by overcharging.
Why does the voltage on a discharged battery measure the same as a fully
charged battery until the loads are applied? The simple answer to this might go as
follows: A battery creates electrical power by converting energy from a chemical
reaction into electrical energy. As this reaction slows down the battery voltage will
drop. In a lead acid battery the electrolyte conductivity (how well electrical current
can flow through it) changes. The same current may be available but the rate of
the reaction decreases, causing a voltage drop.
Another way of looking at this is to use the analogy of a water pump (a battery
is an electric pump). The pressure in psi (pounds per square inch) that a pump
delivers is like a battery’s voltage. The volume of water in GPM (gallons per
minute) is like the electrical current. Look at a 12 psi pump with no loads (the
pump is running but the outflow valve is turned off). The pump will run and the
internal pressure of the pump will build up to some point higher than 12 psi. When
the valve is opened, and the water is free to flow into the loads, the pressure will
drop to the rated output pressure of 12 psi, but only if the load is not too big. If the
pump is designed to maintain 12 psi at 15 GPM, and a load demanding 20 GPM is
connected, the pump will not be able to keep up and the pressure will get sucked
down to a lower psi. If the load is reduced or removed the pump will catch up and
return to its rated 12 psi pressure. If the pump has an infinite source of water, such
as a lake or the water utility (this is like the grid, no battery), the pump will never
run out of pressure. If the pump never runs out of pressure, and is operated at or
below its 15 GPM level, it will hold 12 psi. However, a pump that is connected to
a water tank with a finite capacity will start to lose the ability to hold pressure as
the level of water in the tank drops. Think of siphoning water from a bucket. As
the level of the water drops, the volume of water exiting the siphon slows down.
Battery Voltage &
Current