Blue Sky Energy Solar Boost 3024i Series Manual Addendum

Purpose

This manual addendum applies to the Solar Boost 3024i family of charge controllers which have received the DUO-Option upgrade part number
Upgrade/3024DUO. This addendum should be used in conjunction with the standard product manuals.
The DUO-Option
The 3024 includes a 20 amp auxiliary output. The basic DUO-Option is a software only upgrade which converts the auxiliary output into a separate
20 amp Diversion type charge controller. The DUO-Option upgrade allows a 3024 to provide Diversion type charge control for hydroelectric, wind
or similar unregulated DC generator type power sources while at the same time providing MPPT type PV charge control.
What is Diversion type charge control?
The core purpose of any charge controller is to prevent battery voltage from exceeding a certain charge voltage setting during charging by reducing
charge current delivered to the battery. A battery will charge if PV modules or a wind generator was connected directly to a battery without a
charge controller, but as battery state of charge rises so does battery voltage. Without a charge controller voltage can rise so high once the battery
is charged that the battery or attached systems may be damaged. The Series Pass type charge control in the 3024's MPPT system reduces current
delivered to the battery when necessary to control battery voltage by reducing the current it draws in from the PV and "passes through" to the
battery. By contrast Diversion type charge control has the power source connected directly to the battery. When charge current needs to be
reduced to control battery voltage the Diversion controller "diverts or redirects" a portion of the power source charge current away from the
battery as the means it uses to limit net battery charge current and control battery voltage. The diverted current is typically dissipated as heat in a
resistive dump load.
Diversion charge control operation
When multiple 3024's are networked together without the Diversion control upgrade they essentially operate as separate PV power controllers
under the direction of a single charge control system. Charge voltage setpoints and all charge control "smarts" reside within the charge control
system. If one or more PV power controllers receives PV input power the charge control system starts and directs the activities of the one or more
PV power controllers to deliver the 3024's sophisticated multi-stage battery charge control. The Diversion control upgrade creates a completely
separate 100Hz Pulse Width Modulation (PWM) Diversion type power controller within the 3024 using the 3024's existing 20 amp auxiliary output.
The Diversion power controller has it's own turn on criteria which is when battery voltage reaches the present charge voltage setpoint (typically
14.4/28.8V). When this battery voltage threshold is reached Diversion turns on (whether PV power is present or not) and the Diversion power
controller as directed by the charge control system begins to divert current to a resistive dump load as necessary to reduce net charge current and
control battery voltage. The charge control system then progresses through it's normal multi-stage charge process to precisely control battery
charge.
Min-Power / Max-Power modes
A key aspect of the Diversion control upgrade is it's coordinated interaction with PV charge control. This interaction allows the user to select
whether minimum or maximum possible power is delivered to the dump load. Note that this coordinated interaction occurs within a 3024 only and
not among multiple 3024's on the IPN network. Min-Power / Max-Power mode is selected with 3024 Dip #4.
Diversion
DIP Switch
Operating
#4
Mode
OFF
Min-Power (formerly
Mode Aux
Bat Chg)
ON
Max- (formerly
Power Load
Mode Control)
1
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When battery voltage climbs to the present charge voltage setpoint in the Min-Power mode the PV power
controller reduces current delivered to the battery to control battery voltage in the same manner as a standard
3024. The Diversion power controller remains off until the PV power controller is unable to reduce current
enough to control battery voltage. Once PV output is at a minimum, the Diversion power controller begins to
divert current to the dump load to further reduce net charge current and control battery voltage. Min-Power
mode is typically selected when dump load power is not directed towards a useful purpose and minimum dump
load heating is desired. If no generator is present in Min-Power mode a dump load is unnecessary as the PV
power controller alone controls all charge current.
When battery voltage climbs to the present charge voltage setpoint in the Max-Power mode the PV power
controller continues deliver maximum PV power. While maximum PV power production continues, the Diversion
power controller diverts current to the dump load to reduce net charge current and control battery voltage. If the
Diversion power controller is unable to divert enough current to control battery voltage, the PV power controller
will reduce current to assist in controlling battery voltage while the system as a whole delivers as much power as
possible to the dump load. Max-Power mode is typically selected when dump load power is directed towards a
useful purposes such as heating water. The Max-Power mode may be used with PV power alone if the user wishes
to divert PV power not required for battery charging to a useful purpose. Note that a dump load must be present
in Max-Power mode to ensure stable battery voltage control.
SB3024(D)iL-DUO Manual Addendum
For Models: SB3024iL and SB3024DiL – rev. 430-0027 C
Diversion Control Operation