Xantrex XW-MPPT60-150 User manual

XW Solar Charge
Controller
Owner’s Manual
XW-MPPT60-150

XW Solar Charge Controller
Owner’s Guide

About Xantrex
Xantrex Technology Inc. is a world-leading supplier of advanced power electronics and controls with products
ranging from small mobile units to utility-scale systems for wind, solar, batteries, fuel cells, microturbines, and
backup power applications in both grid-connected and stand-alone systems. Xantrex products include inverters,
battery chargers, programmable power supplies, and variable speed drives that convert, supply, control, clean, and
distribute electrical power.
Trademarks
Xantrex is a registered trademark of Xantrex International.
Other trademarks, registered trademarks, and product names are the property of their respective owners and are used
herein for identification purposes only.
Notice of Copyright
XW Solar Charge Controller Owner’s Manual © January 2008 Xantrex International. All rights reserved.
Exclusion for Documentation
UNLESS SPECIFICALLY AGREED TO IN WRITING, XANTREX TECHNOLOGY INC. (“XANTREX”)
(A)MAKES NO WARRANTY AS TO THE ACCURACY, SUFFICIENCY OR SUITABILITY OF ANY TECHNICAL OR OTHER
INFORMATION PROVIDED IN ITS MANUALS OR OTHER DOCUMENTATION.
(B)ASSUMES NO RESPONSIBILITY OR LIABILITY FOR LOSSES, DAMAGES, COSTS OR EXPENSES, WHETHER SPECIAL,
DIRECT, INDIRECT, CONSEQUENTIAL OR INCIDENTAL, WHICH MIGHT ARISE OUT OF THE USE OF SUCH INFORMATION.
THE USE OF ANY SUCH INFORMATION WILL BE ENTIRELY AT THE USER’SRISK; AND
(C)REMINDS YOU THAT IF THIS MANUAL IS IN ANY LANGUAGE OTHER THAN ENGLISH, ALTHOUGH STEPS HAVE BEEN
TAKEN TO MAINTAIN THE ACCURACY OF THE TRANSLATION, THE ACCURACY CANNOT BE GUARANTEED. APPROVED
XANTREX CONTENT IS CONTAINED WITH THE ENGLISH LANGUAGE VERSION WHICH IS POSTED AT www.xantrex.com.
Date and Revision
January 2008 Revision B
Part Number
975-0400-01-01
Product Number
865-1030-1
Contact Information
Telephone: [phone] (toll free North America)
1 360 925 5097 (direct)
Fax: [phone] (toll free North America)
1 360 925 5143 (direct)
Email: [email protected]
Web: www.xantrex.com

975-0400-01-01 iii
About This Guide
Purpose
The purpose of this Guide is to provide explanations and procedures for installing,
configuring, operating, and troubleshooting the XW Solar Charge Controller (XW
SCC).
Scope
This Guide provides safety guidelines, detailed planning and setup information,
procedures for installing the unit, as well as information about operating and
troubleshooting the unit. It does not provide details about particular brands of
photovoltaic (PV) panels. You need to consult individual PV manufacturers for
this information.
Audience
This Guide does not provide sufficient information for anyone but a qualified
installer to install this product. Installers should be electricians or technicians fully
educated on the hazards of installing electrical equipment. The monitoring and
operation information in this manual is intended for anyone who needs to operate
the XW Solar Charge Controller.
Organization
This Guide is organized into five chapters and two appendices.
Chapter 1 describes features and functions of the XW Solar Charge Controller.
Chapter 2 contains information and procedures to install the XW Solar Charge
Controller. Before installing the XW SCC, read this entire chapter. Depending on
your installation, you may need to perform certain installation stages in a different
order than the order presented in this chapter.
Chapter 3 contains information and procedures to configure the XW Solar Charge
Controller.
Chapter 4 contains information about the operation of the XW Solar Charge
Controller.
Chapter 5 contains information about identifying and resolving possible problems
with systems using a XW Solar Charge Controller.
Appendix A provides the specifications for the XW Solar Charge Controller.

About This Guide
iv 975-0400-01-01
Appendix B is a guide to the XW Solar Charge Controller monitoring and
configuration menus on the XW System Control Panel. The System Control Panel
may be installed if the XW SCC is part of a power management system that
includes an inverter/charger.
Conventions Used
The following conventions are used in this guide.
Related Information
You can find more information about Xantrex Technology Inc. as well as its
products and services at www.xantrex.com.
WARNING
Warnings identify conditions that could result in personal injury or loss of life.
CAUTION
Cautions identify conditions or practices that could result in damage to the unit or to other
equipment.
Important: These notes describe things which are important for you to know, but not as
serious as a caution or warning.

975-0400-01-01 v
Important Safety Instructions
General Safety Instructions
• All electrical work must be done in accordance with local, national, and/or
international electrical codes.
• Before installing or using this device, read all instructions and cautionary
markings located in (or on) this guide, the unit, the batteries, PV array, and
any other equipment used.
• This product is designed for indoor mounting only. Do not expose this unit to
rain, snow or liquids of any type.
• To reduce the chance of short-circuits, use insulated tools when installing or
working with the unit or any DC source (such as PV, hydro, wind, or
batteries).
• Remove all jewelry when installing or working with the unit or any DC
source. This will greatly reduce the chance of accidental exposure to live
circuits.
• The unit contains more than one live circuit (batteries and PV array). Power
may be present at more than one source.
• This product contains no user-serviceable parts.
Battery Safety Information
• Always wear eye protection when working with batteries.
WARNING
This manual contains important safety instructions that should be followed during the
installation and maintenance of this product. Be sure to read, understand, and save these
safety instructions.
WARNING: Limitations on use
The XW Solar Charge Controller is not intended for use in connection with life support
systems or other medical equipment or devices.
WARNING
A battery can produce the following hazards to personal safety:
• electrical shock
• burn from high-short-circuit current
• fire or explosion from vented gasses.
Observe proper precautions when working with or around batteries.

Safety
vi 975-0400-01-01
• Remove all jewelry before working with batteries.
• Never work alone. Have someone assist you with the installation or be close
enough to come to your aid when working with batteries.
• Always use proper lifting techniques when handling batteries.
• Always use identical types of batteries.
• Never install old or untested batteries. Check each battery’s date code or label
to ensure age and type.
• Batteries should be installed in a well-vented area to prevent the possible
buildup of explosive gasses. If the batteries are installed inside an enclosure,
vent its highest point to the outdoors.
• When installing batteries, allow at least 1 inch of air space between batteries
to promote cooling and ventilation.
• NEVER smoke in the vicinity of a battery or generator.
• Always connect the batteries first, then connect the cables to the inverter or
controller. This will greatly reduce the chance of spark in the vicinity of the
batteries.
• Use insulated tools when working with batteries.
• When connecting batteries, always verify proper voltage and polarity.
• Do not short-circuit battery cables. Fire or explosion can occur.
• In the event of exposure to battery electrolyte, wash the area with soap and
water. If acid enters the eyes, flood them with running cold water for at least
15 minutes and get immediate medical attention.
• Always recycle old batteries. Contact your local recycling center for proper
disposal information.
FCC Information to the User
This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference when the equipment is
operated in a residential environment. This equipment generates, uses and can
radiate radio frequency energy and, if not installed and used in accordance with
the instruction guide, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or more of the
following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and the receiver.
• Connect the equipment to a different circuit from that to which the receiver is
connected.
• Consult the dealer or an experienced radio/TV technician for help.

975-0400-01-01 vii
Important Safety Instructions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -v
1 Introduction
Features - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–2
Maximum Power Point Tracking - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–3
Charge Controlling - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–4
Three-Stage Battery Charging - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–4
Bulk Stage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–4
Absorption Stage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–5
Float Stage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–5
Two-Stage Battery Charging - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–6
No Float Stage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–6
Battery Temperature Compensation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–7
Equalization Charging - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–7
Auxiliary Output Functions- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–8
Load Control - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–8
Vent Fan - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–8
Alarms - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–8
Automatic PV Array Night Disconnect - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1–8
2 Installation
PV Array Requirements - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–2
MPPT Voltage Range - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–2
Mounting - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–3
Choosing a Location - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–3
Removing the Wiring Compartment Cover - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–5
Removing Knockouts - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–5
Mounting the Charge Controller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–7
Grounding - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–7
Internal Ground Fault Protection - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–8
Disabling Ground Fault Protection for Negative Grounded and Ungrounded Arrays - - - - - - - 2–9
Wiring- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–10
DC Terminal Connector Locations - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–10
Wire Size and Over-current Protection Requirements - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–10
Current Rating - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–10
Minimum Wire Gauge - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–11
Over-current Protection - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–11
Long-distance wire runs - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2–11
Contents

Contents
viii 975-0400-01-01
Maximum One-way Distance and Wire Size - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–12
Connecting the XW SCC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–13
Connecting Multiple Units- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–15
Aux Output Connections - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–16
Disconnecting the Charge Controller - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–17
Network Installation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–18
Network Components - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–18
Ordering Network Components - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–19
Network Layout - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–19
Connecting Network Cable Between Multiple Units - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–20
Installing the Battery Temperature Sensor - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–21
Commissioning - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–23
Configuration Screens - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2–23
Commissioning a Single Unit Without a System Control Panel - - - - - - - - - - - - - - - - - - - -2–24
Commissioning Multiple Units Without a System Control Panel - - - - - - - - - - - - - - - - - - -2–25
Commissioning Units Using a System Control Panel - - - - - - - - - - - - - - - - - - - - - - - - - - -2–27
3 Configuration
Configuring the XW SCC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3–2
Configuration Menus - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3–3
Basic and Advanced Menus - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3–3
Configuring Battery Characteristics and Battery Charging - - - - - - - - - - - - - - - - - - - - - - - - - - 3–5
Setting a Custom Battery Type - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3–8
Battery Temperature Compensation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–10
Configuring XW SCC Input- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–11
Configuring the Auxiliary Output - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–12
Trigger Source Descriptions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–14
Trigger Source Configurable Ranges - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–15
Configuring the LCD - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–16
Device Menu - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–18
Resetting to Factory Defaults - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -3–20
4 Operation
Viewing Operating Status - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–2
LCD Screens and What They Mean - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–2
Normal Operation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–3
Charge Stages - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–5
Dynamic Text - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–6
Monitoring XW SCC Operation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–7
Viewing Active Faults and Warnings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–8
Viewing Logged System Data - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4–11

Contents
975-0400-01-01 ix
Daily Logs - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–12
Monthly Logs - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–12
Battery Equalization - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4–13
5 Troubleshooting
PV Charge Control Troubleshooting- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5–2
Replacing the Ground Fault Protection Fuse - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5–3
A Specifications
Electrical Specifications - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–2
Default Battery Charging Settings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–2
Mechanical Specifications - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–3
Output Power Versus Ambient Temperature - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–3
Optional Accessories - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–4
Regulatory Approvals - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -A–4
B XW System Control Panel Menus
Using the XW System Control Panel - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–2
System Control Panel Menu Map - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–3
Changing Settings Using the System Control Panel - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–5
Viewing the Select Device Menu - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–5
Viewing the XW SCC Setup Menu - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–5
The Charge Controller Setup Menu - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–6
Configuration Settings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–7
Monitoring the XW SCC - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–10
XW SCC Home Screen - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–10
Meters - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -B–11
Warranty and Return Information - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - WA–1
Index - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - IX–1

x

1Introduction
Chapter 1 describes features and functions of the XW Solar Charge
Controller.
For information on: See:
“Features” page 1–2
“Maximum Power Point Tracking” page 1–3
“Charge Controlling” page 1–4
“Auxiliary Output Functions” page 1–8
“Automatic PV Array Night Disconnect” page 1–8

Introduction
1–2 975-0400-01-01
Features
The XW Solar Charge Controller (XW SCC) is a photovoltaic (PV) charge
controller that tracks the maximum power point of a PV array to deliver the
maximum available current for charging batteries. The XW SCC can be used with
12-, 24-, 36-, 48-, and 60-volt DC battery systems.
The XW SCC is designed to regulate PV input, but will also work with other DC
sources. The DC source must meet the specifications listed on page A–2.
The XW SCC can be installed (in single or multi-unit configurations) with a
Xantrex XW Hybrid Inverter/Charger or in a stand-alone installation.
Standard features of the XW Solar Charge Controller include:
• Two- or three-stage charging process, with manual equalization to maximize
system performance and maintain expected battery life.
• True dynamic Maximum Power Point Tracking (MPPT) to deliver the
maximum available power from a PV array to a bank of batteries. See
“Maximum Power Point Tracking” on page 1–3.
• Integrated PV Ground Fault Protection (PV-GFP).
• Convection cooled (no internal or external fan) using aluminum die-cast
chassis and heat sink.
• 60-amp capacity.
• Configurable auxiliary output. See “Auxiliary Output Functions” on page 1–8.
• Two-line, 16-character liquid crystal display (LCD) and four buttons for
configuration and system monitoring.
• Input over-voltage and under-voltage protection, output over-current
protection, and backfeed (reverse current) protection. Warning and Fault
messages appear on the LCD when the unit shuts down as a protective
measure.
• Over-temperature protection and power derating when output power and
ambient temperature are high.
Figure 1-1 XW Solar Charge Controller

Maximum Power Point Tracking
975-0400-01-01 1–3
• Battery Temperature Sensor (BTS) to provide automatically temperature-
compensated battery charging. If the BTS is lost or damaged, a replacement
can be ordered from Xantrex (part number 808-0232-02).
• Xanbus®-enabled. Xanbus is a network communications protocol developed
by Xantrex. The XW SCC is able to communicate its settings and activity to
other Xanbus-enabled devices, such as the XW Series Inverter/Charger, the
XW System Control Panel (SCP), XW Automatic Generator Start (XW-
AGS), and other XW Solar Charge Controllers.
• Five-year limited warranty.
Maximum Power Point Tracking
Maximum Power Point Tracking allows the XW SCC to harvest the maximum
energy available from the PV array and deliver it to the batteries.
The MPPT algorithm continuously adjusts the operating points in an attempt to
find the maximum power point of the array. The algorithm can then determine if it
is harvesting more or less power than the previous operating points.
The XW SCC applies a variable load on the array—shown by the power curve
(solid line) in Figure 1-2—until it finds the maximum wattage (the point at which
both operating voltage and current can be maximized at the same time), as
indicated by “MPP” in Figure 1-2. The XW SCC then holds the array at this point
for as long as the array continues to produce the maximum power possible. As
panel shading, cloud cover, and sunlight angle shift, the XW SCC finds the new
maximum power point without interrupting its output power flow.
Figure 1-2 Maximum Power Point Curve
20
18
16
14
12
10
8
6
4
2
0
Current (I) Amps
0102030405060708090
Voltage (V) Volts
Isc
Imp
MPP
Vmp Voc
Watts

Introduction
1–4 975-0400-01-01
Charge Controlling
The XW SCC can regulate PV array current at 12, 24, 36, 48 or 60 volts DC for
charging batteries. It produces up to 3500 watts and 60 amps of charging current
for all battery voltages except 60 volts.
The XW SCC controls how the batteries are charged by the DC source (the PV
array). It can be configured to use a two-stage (“No Float”) or three-stage
charging process to maintain battery voltage at bulk or float levels.
When charging, the XW SCC regulates the battery voltage and the output current
based on the amount of DC power available from the PV array and the state of
charge of the battery.
The XW SCC is able to charge a lower nominal-voltage battery from a higher-
nominal voltage array. For example, the XW SCC can charge a 12-volt battery
from a 36-volt array. This gives flexibility to installers to use longer wiring runs
without compromising efficiency on a higher-voltage array.
The XW SCC is not able to charge a higher-voltage battery from a lower-voltage
array.
Three-Stage Battery Charging
The three-stage charging process results in more efficient charging compared to
on-off relay type or constant voltage solid-state regulators. The final float stage
reduces battery gassing, minimizes electrolyte loss, and ensures complete battery
recharging. Battery voltage and current vary during the three-stage charging
process as shown in Figure 1-4 on page 1–5.
Bulk Stage
During the bulk stage, the XW SCC sets its voltage limit to the bulk voltage
setting. If the batteries are discharged, the XW SCC operates in constant current
mode, delivering its maximum current to the batteries. When the battery voltage
reaches the Float voltage setting, the controller will transition to the absorption
stage.
Figure 1-3 PV Charge Controller

Charge Controlling
975-0400-01-01 1–5
Absorption Stage
During the absorption stage, the XW SCC continues to deliver its maximum
available current output until the battery voltage reaches the absorption voltage
setting. The XW SCC then operates in constant voltage mode, holding the battery
voltage at the absorption voltage setting for a pre-set time limit (the default time
limit is three hours). During this time, current falls gradually as the battery
capacity is reached. The XW SCC transitions to the float stage if any one of three
criteria are met:
1. The charge current allowed by the batteries falls below the exit current
threshold, which is equal to 2% of battery capacity (for a 500 amp-hour
battery bank, this would be 10 amps), for one minute.
2. The battery voltage has been at or above the float voltage (which it reached
during the bulk stage) for eight hours.
3. The battery voltage has been at the bulk/absorption voltage setting for a pre-
set time limit (the Max Absorb Time).
Float Stage
During the float stage, the voltage of the battery is held at the float voltage setting.
Full current can be provided to the loads connected to the battery during the float
stage from the PV array. When battery voltage drops below the ReCharge Volts
setting for 1 minute, a new bulk cycle will be triggered.
Figure 1-4 Three-stage Battery Charging Cycle
a
a.An actual charging cycle for a PV-based system that is in use while it is being charged will
likely differ from the cycle represented in Figure 1-4. This is because a PV system’s output
is limited by the amount of solar energy available, and also because DC loads will affect the
charge current and the measured battery voltage.
Time
Float Stage
Absorption Stage
Bulk Stage
Absorption—
constant current Absorption—
constant voltage
Current
Voltage
Time
Bulk/Absorption Voltage
Float Voltage Threshold
ReCharge Voltage Threshold
Exit Current Threshold
Max Absorb Time—3 hours
(adjustable 2–6 hours)
Max Current Limit
Maximum 8 hours (fixed)
Float voltage
Bulk Stage Absorption Stage Float Stage

Introduction
1–6 975-0400-01-01
Two-Stage Battery Charging
The two-stage charging process includes the bulk and absorption stages, but uses a
“No Float” stage instead of “Float.” The relationship between charging current
and battery voltage during the two-stage charging process is shown in Figure 1-5.
No Float Stage
During the No Float stage the XW SCC does not produce any charge current.
Instead the XW SCC monitors the battery voltage and transitions back to the bulk
stage once the voltage drops below the ReCharge Volts setting for one minute.
Note: For more information about battery charging settings, see Table 3-2, “Battery
Menu Values” on page 3–6 and Table 3-3, “Custom Battery Menu Values” on page 3–8.
Figure 1-5 Two-Stage Battery Charging Cycle
Time
Float Stage
Absorption Stage
Bulk Stage
Absorption—
constant current Absorption—
constant voltage
Current
Voltage
Time
Bulk/Absorption Voltage
ReCharge Voltage Threshold
Exit Current Threshold
Max Absorb Time—3 hours
(adjustable 2–6 hours)
Max Current Limit
Maximum 8 hours (fixed)
Float Voltage
Bulk Stage Absorption Stage No Float Stage
Return to Bulk Stage

Charge Controlling
975-0400-01-01 1–7
Battery Temperature Compensation
The Battery Temperature Sensor (BTS) automatically adjusts the charging process
of the XW SCC. With the BTS installed, the XW SCC increases or decreases the
battery charging voltage depending on the temperature of the battery to optimize
the charge to the battery and to protect it from over-charge or damage. Using the
BTS can extend battery life and improve overall charging.
The BTS plugs into the BTS jack located inside the wiring compartment of the
XW SCC. The BTS can be installed on the negative battery post or on the side of
the battery.
If the BTS is not installed, the voltage settings for charging are based on one of
three temperature settings (Cold, Warm, or Hot) available on the XW SCC
configuration menu. See “Configuring Battery Characteristics and Battery
Charging” on page 3–5.
Only one BTS is required if multiple XW SCCs or a complete XW Power System
with XW Series Inverter/Chargers are networked together using Xanbus. All
networked XW Series devices share battery temperature information, and the BTS
can be connected to a XW SCC or an XW Inverter/Charger.
Equalization Charging
The XW SCC can be used to provide the battery bank with an equalize charge.
Equalization is a deliberate overcharge designed to return each battery cell to
optimum condition by reducing sulfation and stratification in the battery. The
equalization charge is generally performed only on flooded, vented (non-sealed or
“wet”) lead-acid batteries, as recommended by the battery manufacturer.
To avoid damaging your batteries, be sure to read all cautions and warnings
concerning equalization charging. For more information, see “Battery
Equalization” on page 4–13.
Figure 1-6 Battery Temperature Sensor
Important: The XW SCC maximum output voltage is limited to 72 volts for a 60-volt
battery system, which is the bulk voltage setting for 60-volt batteries. Because of this
output limit, the XW SCC does not equalize 60-volt batteries.

Introduction
1–8 975-0400-01-01
Auxiliary Output Functions
The XW SCC has a configurable auxiliary output (producing 5 to 13 volts and up
to 200 milliamps) to drive a relay for load control or to turn on devices such as
vent fans or indicator alarms. The auxiliary output can be configured to perform
only one function at a time.
See “Configuring the Auxiliary Output” on page 3–12 for information about
auxiliary output trigger sources and how to enable and configure the auxiliary
output for your application.
Load Control
The XW SCC auxiliary output can be configured to drive a relay to disconnect or
reconnect loads depending on battery voltage. This load control function enables
the XW SCC to help prevent damage to the battery from over-discharge during
periods of poor charging (due to ambient temperature, for example) or excessive
loads.
Vent Fan
The XW SCC auxiliary output can be configured to power a small DC fan to clear
a battery compartment of harmful gases. The XW SCC auxiliary output must be
configured to activate when the batteries reach their gassing voltage.
Alarms
The auxiliary output can be configured to trigger an alarm or indicator light when
a pre-set condition occurs, such as low or high battery voltage, high PV array
voltage, or a XW SCC fault.
Automatic PV Array Night Disconnect
At night, or when the PV array voltage is less than the battery voltage, the XW
SCC opens an internal relay to prevent battery current from flowing back to the
PV array. In this mode of operation the XW SCC draws minimal power from the
battery.
This automatic night-time disconnect eliminates the need for a blocking diode
between the battery and the PV array. If the PV array consists of thin-film or
amorphous solar modules, diodes may still be required to prevent damage during
times of partial shading of the array. Check the documentation provided with the
PV modules.
CAUTION
The auxiliary output is intended only to energize a low-current circuit such as a relay coil.
Connection to a high-amperage device will open the fuse in the common line and possibly
damage the unit.