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PV7-PV14 manual.doc
The
Flexcharge
TM
Energy State Taper Charge Process
Monitors the battery for the full charged resting voltage of the cells.
Discover the tremendous advantages with this charge method.
Zero overcharging
Exceptionally low gassing (Up to 90% less)
No RFI or EMI emissions to interfere with radio equipment.
Non-Destructive Micro-Equalization at each full charge
The chemical processes of the battery actually control the charging.
The need for temperature compensation is also greatly reduced because the plate voltage is not held
constantly at the critical plate saturation voltage. Voltage Tapering is controlled by the battery's level of charge
rather than with timers, or fixed voltages as in PWM and other constant voltage charge methods. The battery
takes exactly what it needs rather than being forced to take a set voltage. With the Flexcharge method, you
can charge your battery bank indefinitely without any possibility of overcharging. The batteries will last longer,
require less watering maintenance, and hold a better charge.
As charging begins the controller allows full charging current to pass directly to the battery. When the battery
voltage rises slightly above the plate saturation point, the controller opens the charging circuit. Much like a
sponge will continue to absorb water towards its center after it has taken it all into its surface, the chemical
charging process continues after the charging current has been removed. As the charge is absorbed, the
battery's voltage will fall. When the battery voltage has floated down to approximately 13.5V to 13.8V it is
ready to accept another charge pulse. This charge regulation method is actually controlled by the battery's
ability to accept and absorb energy. When the battery needs more energy indicated by plate voltage, the
controller applies it. Mid way in the charging process, the controller will cycle ON and then OFF sending full
charge current pulses into the plates. A process, which charges with very low gassing, and equalizes the
plates with each full charge. As the battery reaches a higher level of charge, the amount of time the controller
spends in charge is reduced, and the time in rest is increased. At full charge, the controller will apply short
duration pulses to maintain the battery at an average voltage of about 13.75 volts. This keeps gassing to a
minimum while effectively trickle charging, and equalizing at the same time.
There has been a great deal of discussion over which charge process is better, PWM, or this method. To add
fuel to the fire, each company making "ON-OFF" controllers has chosen different voltages to set the
disconnect and reconnect points. A number of PWM controller manufacturers have gone to great lengths to
discredit “Low Frequency PWM or ON-OFF regulators” by studying a controller that was not set up with the
proper connect/reconnect voltages. At Flexcharge we have analyzed controllers using a version of this
method where the reconnect voltage on a 12V system was set at 12.6V @ 70°F. On this system the batteries
would never see more than 80% charge, and likely much less. Obviously PWM type controllers will regulate
the charging of your batteries. With proper temperature compensation, heat sinks, and the correct Bulk-
Regulate-Float (3 stage) algorithm will do a pretty good job of it, but why settle for this when you can get so
much more in a charge regulator. Instead of three stages with PWM you get an infinitely variable charge
process which will supply the battery with exactly what it needs, only when it needs it. You will realize less
plate saturation gassing, non-destructive equalization and Zero EMI and RFI as well. Electrico-Magnetic-
Interference, and Radio Frequency Interference is electronic noise that can interfere with radio and navigation
equipment.
Charge Controllers using the Energy State Taper Charge are best suited for charging systems where the
charging current is less than 1/4 of the amp hour rating of the battery bank. If your charging system is
designed to charge at a rate higher than 1/4 the battery bank's capacity, then the power switching element
should be solid state to provide the longer term reliability. At Flexcharge we make use of both types of
switching elements in our controllers depending on the task. They are implemented in such a way as to
provide exceptional levels of dependability. To determine these ratings, first add up the total amp/hour
capacity of your battery bank then divide that number by 4. If the result is larger than the maximum current
your charging source can produce, then the Energy State Taper Charge Process is the best method for your
system.
