Blue Sky Solar Boost 3024iL DUO-Option - Manual

Page 1 of 4
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
Operating
Mode
DIP
Switch
#4
Diversion Control Operation
Min-Power
Mode
OFF
(formerly
Aux Bat
Chg)
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.
Max-Power
Mode
ON
(formerly
Load
Control)
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.
SB3024iL DUO-Option Manual Addendum
For Models; SB3024i, SB3024Di, SB3024iL, SB3024DiL