Merlin SmartGauge Installation Manual

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 1

SmartGauge Installation and User Guide

Merlin Power Systems

Unit 4, Cabot Business Village

Holyrood Close

Poole, Dorset BH17 7BA

T: [phone]
F: [phone]

www.merlinpowersystems.com

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 2

Merlin’s SmartGauge battery monitoring system is designed to provide highly accurate battery
voltage and SoC (State of Charge) information in a reliable, easy to use package.
Simple to install, the SmartGauge monitor provides much more accurate battery state information

than conventional “amp hour counters”, all without the need for installing additional shunts and

heavy cabling.

As the Merlin SmartGauge significantly differs from most battery monitoring equipment, please
take time to carefully read this manual in order to understand the correct method of installation
and user functions. Failure to do so may result in permanent damage to the SmartGauge and/or
other electrical systems.

Once the unit has been correctly installed, the benefits of acquiring the Merlin SmartGauge will
become fully evident.
If any questions arise after reading this manual, further technical support can be obtained from your
local dealer or Merlin Power Systems directly:

Europe: Tel: [phone] North America: Tel: [phone]

CONTENTS OF THIS GUIDE

1.0 Introduction Page 2

1.1 Main SmartGauge Features Page 3

1.2 Why SmartGauge? Page 3

1.3 Certificates of Conformity / Caution Notes Page 4

2.0 Quick Start Guide Page 5

3.0 SmartGauge Installation Basics Page 8

3.1 Important Installation Notes Page 8

3.2 Initial Start-Up Page 9

3.3 Battery Charge Status Page 9

3.4 Power Up after Power Loss Page 10

4.0 Basic Monitor Use Page 11

5.0 Set-Up Menu - Introduction Page 12

5.1 Set Up Menu – Battery Types Page 13

5.2 Set Up Menu – Charge Status Page 14

5.3 Set-Up Menu – Alarm Functions Page 14

5.4 Set-Up Menu – Primary Alarms Page 15

5.5 Set-Up Menu – Secondary Alarms Page 18

5.6 Set-Up Menu – Defeating Error Codes Page 19

5.7 Set-Up Menu – Displays Page 19

5.8 Set-Up Menu – Display Brightness Page 20

5.9 Set-Up Menu – Menu Lock Page 20

6.0 Error Codes Page 20

7.0 Reset to Factory Defaults Page 22

8.0 Alarm Outputs Page 22

9.0 SmartGauge in Conjunction with SmartBank Page 22

9.1 Warranty Page 23

10.0 SmartGauge Flowcharts Page 24/25

1.0 Introduction

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 3

Monitoring and Display of Auxiliary Battery Voltage
Monitoring and Display of Auxiliary Battery State of Charge (SoC)
Monitoring and Display of Secondary Battery Voltage
User Defined High/Low Battery Voltage Alarms for Each Battery
User Defined High/Low SoC Alarm for Auxiliary Battery
Bright LED Daylight Display Screen
Volt Free Alarm Contact for Firing External Alarms, Relays etc

Conventional battery monitor systems count amp hours in/out of the batter to determine SoC. This
method is inherently inaccurate due to the SoC of the battery not necessarily being linked to the
amount of energy a battery can deliver. Factors such as temperature, battery charge/discharge rate,
incorrectly installed shunts and battery age all contribute to this inaccuracy. Unless the conventional
battery monitor is regularly reset (either automatically by fully charging the battery or manually), the
reading error will compound (known as synchronisation error).

For batteries being used in standby (nominal zero current) applications, Amp Hour counters will run
out of synchronisation as there are very low or no amps flowing through the shunt. Self discharge of
the batteries cannot be accounted for so, simply by just not using your electrical system, an amp
hour counter will display incorrect State of Charge Values.

SmartGauge uses just two wires to monitor the battery. Proprietary test methods are employed by
the SmartGauge to generate data. This data is then compared to detailed computerised battery
models. SmartGauge compares real world data with those models to generate SoC information. In
independent testing SmartGauge was found to be within 5% accuracy at all times.

Highly accurate SoC information not only allows you to confidently make decisions about how you
use your electrical system, it also allows you to automate certain functions like load shedding or
generator start/stop.

SmartGauge uses a self-correcting algorithm to determine battery SoC – over time it becomes more
and more accurate. This self-correction also means that SmartGauge automatically adjusts for
battery degradation over time. SmartGauge only needs 2-3 charge/discharge cycles to synchronize
with the batteries.

SmartGauge also interfaces with the Merlin SmartBank for highly advanced split charging – see
SmartBank manual for details.

1.1 Main SmartGauge Features

1.2 Why SmartGauge?

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 4

Declaration of Conformity

Merlin Equipment Limited, Trading as Merlin Power Systems hereby declares that the product
marketed as SmartGauge is in compliance with the requirements of EU Electromagnetic
Compatibility (EMC) Directive 89/336/EEC.

SmartGauge complies with RoHS (Reduction of Hazardous Substances) Directive 2002/95/EC.
SmartGauge contains no Lead. At the end of life, SmartGauge should be disposed of as normal
electrical waste.

SmartGauge has been tested to and surpasses ISO-7637-2 for use on vehicles.

James Hortop
Managing Director
Merlin Power Systems UK

Date: 25

th

January 2013

CAUTIONS AND WARNINGS

CAUTION: Statements within this user guide identified with the word “CAUTION”, relate to practices

that may damage SmartGauge.
WARNING: Statements within this user guide identified with the word “WARNING”, relate to
practices that may cause injury or death.

This main SmartGauge user guide is written with the intention for use by qualified electrical
personnel. It does not identify normal practices or procedures that would indicate normal good
practice expected of a qualified electrical engineer. Please review with the specific professional
body or organization which covers your installation’s Health & Safety and Guidance regarding
good working practices.

1.3 Certificates of Conformity

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 5

CAUTION & WARNING:
Batteries are hazardous
items. Please follow

battery manufacturer’s

recommendations for
health and safety. Use
only the appropriate tools
in conjunction with

manufacturer’s

instructions. Isolate both
battery and AC power
supplies before
attempting installation.

CAUTION & WARNING:
The Quick Start Guide
does not refer to each
and every Caution &
Warning Statement in this
manual. Be sure to
observe safe working
practices at all times.
Refer to the full manual if
you are unsure of any
practices that may
damage the SmartGauge
unit, your system wiring
or health.

This Quick Start guide assumes SmartGauge is being installed for
the first time. Following this guide will enable a first time user to
set up and start using SmartGauge basic functions. If more in depth
functionality is required, or the SmartGauge being used has been
connected to a battery before, please refer to the main sections of
this user guide.

CAUTION! As the Merlin SmartGauge significantly differs from most battery monitoring
equipment, it is highly recommended that the user carefully reads the main section of this user
guide in order to fully understand the correct method of installation and full range of user
functions. Failure to do so may result in permanent damage to the SmartGauge and/or other
electrical systems.

Once the unit has been correctly installed, the benefits of acquiring the Merlin SmartGauge will
become fully evident.
If any questions arise after reading the main section of the user guide, further technical support can
be obtained from your local dealer or Merlin Power Systems directly:

Europe: Tel: [phone] North America: Tel: [phone]

2.0 Quick Start Guide

65.0mm

The SmartGauge display panel is typically mounted at the dash or navigation
area, or in other locations where it can be easily accessed for viewing. The
rectangular display panel requires a rough opening measuring 96.0mm wide
by 65.0mm tall, as illustrated in Figure 1 above. Access to the rear of the
monitor will be required to install ground and positive sense wires from the
monitor directly to the battery banks. In addition, there are terminals for
wiring connections to install separate wires for an audible or visual low­voltage/low-battery capacity alarm.
Once a location has been determined for the monitor panel, sensing and
ground wires can be run to the batteries, as described in Figure 2 on the
following page.

Quick Start
Important Note:

96.0mm

Fig 1

65.0mm

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

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The SmartGauge does not require a separate shunt for installation. Battery voltage and state of
charge are both determined via sense wires connected directly to the terminals of one or both
battery banks. Referencing figure 2 below, to install:

1. An 18 gauge (AWG) ground wire from the GND terminal on back of the Smart-Gauge to the

battery negative post of the auxiliary battery bank.

2. An 18 gauge (AWG) positive sense wire from the B1 terminal on SmartGauge to the battery

positive post of the main battery bank. This wire must be fused at 3 amps with the fuse
holder installed as close to the battery as possible – note that the fuse should be outside any
battery compartment where battery gases may accumulate. It should not be run to busbars,
isolation switches, fuse panels etc.

3. If a second battery is to be monitored for voltage, run an additional 18 gauge (AWG) wire,

fused at 3 amps, from the B2 terminal on SmartGauge to the positive battery post of the
second battery bank or engine start bank. Again, this fuse should be located as close to the
battery as possible (but not inside the battery compartment if combustible gases can build
up).

AUX BATTERY
BANK

-VE

Rear View of SmartGauge

TO SYSTEM GROUND

-VE

-VE

-VE

3A FUSE

3A FUSE

+VE

+VE

+VE

+VE

ENGINE BATTERY
BANK

Fig 2

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

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Number Battery type

1 Deep cycle, wet cell, antimony lead acid
2 Gel Cell lead acid (a type of VRLA – Valve Regulated Lead Acid)
3 AGM – Absorbed Glass Matt (another type of VRLA)
4 Hybrid – calcium/antimony (usually marked as dual purpose or “leisure”) lead acid
5 Carbon Fibre lead acid
6 Maintenance free (wet cells but no way to top up the electrolyte) lead acid

Important Note on Type 3 -Use only for genuine AGM batteries.

Genuine AGM’s have the electrolyte held in a glass mat but with additional chemicals in the battery.
They require lower charge voltages and the off load terminal voltages will be similar to gel cells. Only
this type requires SmartGauge to be set to battery type 3.
There are other Glass Mat type batteries without the additional chemicals. This type usually has
charge voltages very similar to flooded wet cell batteries. The off load terminal voltages will also be
very similar to flooded wet cell batteries. If your AGM batteries are of this type then SmartGauge

should be set to battery type 1.

When the required battery type is in the display, press SET or EXIT. The display will now show
battery voltage, pressing Batt 2 will display the voltage on the second battery and the PGM/Batt 2
LED will be lit.

Pressing the Status button will display the charge status as a percentage from 0 to 100. This will
initially be showing 75% which may or may not be correct. If you know what the charge status of the
battery is you can manually set this to correspond with the batteries. Please refer to section 5.2 of
this user guide if this option is chosen.

Alternatively, if you are currently using the batteries (i.e. regularly discharging and charging them)
you may simply leave SmartGauge to synchronise itself. This will typically take 2 or 3 discharge and
recharge cycles. Synchronisation is not an instant effect. The SmartGauge will continue to track
battery condition with increasing accuracy over time.

This completes the quick start section of this user guide and initial setup of SmartGauge. For
operation and details of further functions and features, continue to refer to the remainder of this
manual.

After connecting as per Figure 2, the display will
briefly show the software and battery model
revisions. These are primarily for diagnostics and
can be ignored by the user.

SmartGauge will then show “bt 1” in the display and

the PGM/Batt 2 LED will be flashing. Use the
Status/Select button to scroll this value up to the
battery type that corresponds with the battery type
of the auxiliary battery bank according to the
following:-

Merlin Power Systems version: 2.0.2

SmartGauge Installation and User Guide

Page 8

The information contained herein relating to installation is for guidance only. It is believed to be
correct at the time of writing. It is the installer’s responsibility to ensure compliance with any relevant
safety regulations, codes of practice, legal requirements etc. The manufacturers, suppliers, dealers
and/or their agents cannot be held responsible for any breach of such requirements as a result of any
information contained herein. Installation of SmartGauge implies acceptance of these terms.

The purpose of this manual is to enable the installer to install SmartGauge in a manner that permits

it to operate as designed. This manual’s purpose is not to educate the installer on the legal

requirements of any particular type of installation. The manufacturer, supplier, dealer and/or their
agents cannot know what the final installation will be and therefore cannot know what the legal
requirements of such installation may be.

Installation of SmartGauge is simple and should be completed in a short time. Only two connections
are required to operate SmartGauge for monitoring a single battery bank system, with only three
wires required for a dual-bank installation.

1. B1 = Battery 1 – this must be the primary auxiliary battery bank being monitored. B2 = secondary
auxiliary bank OR engine start battery.

2. Battery 1 and Battery 2 must both be the same nominal voltage, either both 12 volts, or both 24
volts. SmartGauge cannot be used on a mixed installation of both 12 and 24 volt supplies together.

3. Battery 1 and Battery 2 must share a common negative. It is not possible to install SmartGauge on
two isolated battery systems or on two-battery systems with a common positive.

4. Keep the wires running from the batteries to the SmartGauge as short as possible. Use 18-gauge
(AWG) wire for all connections.

5. In order to comply with most safety regulations and standard good practice, a fuse rated at 3
amps should be fitted in the positive wire as close to the battery as practical but not inside the
battery compartment unless the batteries are certified as safe for use in habitable or sealed
compartments (i.e. usually Gel cells or AGMs) or unless the batteries are externally vented via their
own ventilation system.

6. The SmartGauge battery +ve and –ve must always be connected directly to the battery posts.
Never connect to bus bars, distribution panels, fuse panels or isolation switches. Incorrect
SmartGauge connection will result in false battery monitoring.

7. Never power other loads from the SmartGauge battery sensing cables. If a SmartGauge alarm
function is being used to power a buzzer or lamp for instance, then the alarm equipment must have
its own power feed.

8. If SmartGauge is being installed in an installation with an existing ammeter or amp hour counter
utilising a shunt, then it is normal practice to connect all equipment to the load side of the shunt, not
to the battery side. Leave all other equipment connected in this fashion, but the SmartGauge must
be connected directly to the battery terminals in order to function correctly (the resistance in the
shunt will alter the accuracy of SmartGauge) . The SmartGauge current drain is so low, it will have no
effect on existing ammeter readings.

3.0 SmartGauge Installation Basics

3.1 Important Installation Notes – please read carefully