5
Charge modes and set points:
As introduced above, the HVAD is fully configurable through the front panel buttons and display. There are no
jumpers that need to be set or potentiometers that need to be adjusted. All configurable options are reachable via the
menu system. This menu system is comprised of a main menu and several submenus as depicted above in the menu
layout graphic. Each submenu allows you to either set a particular value, view information, or perform specific
actions, like running a solenoid test or starting the equalize mode. Most of these menu items are self-explanatory and
will not be discussed in detail; however, there are some features and settings that deserve greater explanation.
First and foremost, you generally do not need to change anything. When the controller is first powered up, it
analyzes the current battery voltage to determine whether the battery bank is a 12, 24 or 48-volt bank. If your battery
bank nominal voltage has changed sine the last time the unit was powered up, then the microprocessor will reset all
values to the factory defaults and store the new information. These factory defaults are normally perfectly adequate
for a lead acid battery bank used with most solar and wind installations. Changes to the settings are therefore only
required when your requirements are different in one manner or another from what has been set by the factory. The
controller is basically plug-and-play! Factory defaults can be viewed in the technical specifications page in this
manual.
Although the HVAD is a solenoid-based “Diversion Controller”, it is capable of simulating a 3-stage charge controller
due to the fact that the controller can track both a bulk and float setting. The word simulating is used because no
solenoid or relay based controller can react to instantaneous changes of the battery voltage or limit the current flow in
the same manner as a PWM controller can. This said, the controller is a VERY capable mechanical controller that
does have the ability to track multiple voltages and react accordingly. Additional charging logic has also been added
including such features as re-bulking, an absorb mode that allows for automatic adjustments due to changes in solar
illumination (low current) as well as offering both a manual and automatic equalize. So, this is no stripped down
mechanical controller … but what is a 3-stage charge controller?
The main advantage to solid-state controllers and the very capable HVAD is that they offer more advanced charging
modes than single stage, i.e., mechanical controllers. We will briefly discuss the three stage charging modes.
•
Bulk Charge
•
Absorption Charge
•
Float Charge
The HVAD is capable of providing these 3 stages:
The 1
st
stage in a 3 stage charging mode is the Bulk Charge: In this mode, most (if not all) of the available current is
sent to the batteries to raise the battery voltage up to the bulk set point. This mode brings the battery to about 80% of
its capacity. Generally the bulk charge voltage is set to between 14 and 15 volts, with 14.4 volts often used as a
standard. There is really no perfect voltage setting here as there are many factors involved. The ambient temperature,
the size of the energy sources vs. the battery bank size, the desired length of time in this mode, the cost of the energy
(if it is supplemented by the grid or generator, etc.). Simply stated, the bulk charge gets the battery up to a mostly full
state at a quick but healthy rate.
The 2
nd
stage of the 3 stage charging mode is the Absorption Charge: Once the bulk mode set point is reached, the
charger attempts to hold and track this value. The absorption mode uses the same set point as the bulk mode with the
difference being that the battery voltage is no longer rising up to the set point; but instead, it is being maintained at
that set point. Due to the chemical nature of the battery, this constant voltage causes the charge current to drop as the
battery reaches a “full” state of charge. The factory default for the absorption mode is set to 120 minutes, which under
sufficient solar/turbine energy input is ample to charge most battery banks.
Summary of Contents for C440-HVAD
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