Computronic Controls Guardian User Manual

Guardian series

UL/CSA Approved Automatic Battery Chargers
INSTALLATION AND OPERATION

THIS MANUAL REFERS TO THE FOLLOWING MODULES

G1501210
G3001220
G3002410

G6002420
EG1501210
EG3001220
EG3002410
EG6002420

For safe and correct use of these chargers, read and save the safety
information that precedes the installation and operation instructions.

This guide contains 8 pages (including this one). If any pages are missing,
contact the battery charger supplier or manufacturer for replacement
documentation.

Guardian, open frame (G series)

Enclosed Guardian (EG series)

A division of Frank W Murphy Ltd.

41 – 46 Railway Terrace, Nechells, Birmingham, B7 5NG, United Kingdom
tel: [phone]
fax: [phone]
email: [e-mail]
web: www.computroniccontrols.com

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IMPORTANT SAFETY INFORMATION – READ AND SAVE THESE INSTRUCTIONS

This manual contains important safety and operating instructions for models G150, G300, G600, EG150, EG300
and EG600.

 Do not expose the battery charger to rain, snow or wet environments.
 The use of any attachment not recommended or sold by the battery charger manufacturer may result in risk of fire,

electric shock or injury to persons.

 Do not operate charger if it has received a sharp blow, been dropped, or otherwise damaged in any way: return to

supplier.

 Do not disassemble the charger: return to supplier when service or repair is required. Incorrect re-assembly may result

in a risk of electric shock or fire.

WARNING – RISK OF EXPLOSIVE GASES

WORKING IN THE VICINITY OF A LEAD ACID BATTERY IS DANGEROUS. BATTERIES GENERATE EXPLOSIVE
GASES DURING NORMAL BATTERY OPERATION.

To reduce the risk of battery explosion, follow these instructions and those published by the battery manufacturers and the
manufacturer of any equipment you intend to use in the vicinity of the battery. Review cautionary marking on these
products and any attached equipment.

PERSONAL PRECAUTIONS.

 (i) Someone should be within range of your voice or close enough to come to your aid when you work near a lead-acid

battery.

 (ii) Have plenty of fresh water and soap nearby in case battery acid contacts skin, clothing or eyes.
 (iii) Wear complete eye protection and clothing protection. Avoid touching eyes whilst working near batteries.
 (iv) If battery acid contacts skin or clothing, wash immediately with soap and water. If acid enters eyes, immediately

flood eyes with running cold water for at least 10 minutes and get immediate medical attention.

 (v) NEVER smoke or allow a spark or flame in vicinity of battery.
 (vi) Be extra cautious to reduce risk of dropping a metal tool on to the battery. It may spark or short-circuit the battery or

other electrical part that may cause explosion.

 (vii) Remove personal metal items such as rings, bracelets, necklaces and watches when working with a lead-acid

battery. A lead–acid battery can produce a short-circuit current high enough to weld a ring or the like to metal, causing
a severe burns.

 (viii) Use the charger only for charging batteries as stated on the charger. Do not use the battery charger for charging

dry-cell batteries that are commonly used with home appliances. These batteries may burst and cause injury to persons
and damage to property.

 (ix) NEVER CHARGE A FROZEN BATTERY

PRIOR TO INSTALLATION /COMMISSIONING

 Clean battery terminals. Be careful to keep corrosion from coming into contact with eyes.
 Add distilled water in each cell until the battery acid reaches a level specified by battery manufacturer. This helps purge

excessive gas from the cell. Do not overfill. For a battery without cell caps, carefully follow manufacturer’s recharging

instructions.

 Study all battery manufacturer’s specific precautions, such as removing or not removing cell caps while charging and

recommended rates of charge.

 Determine the voltage of battery by referring to engine manual and ensure this matches the charger’s output voltage.

CHARGER LOCATION AND CONNECTION

 Never place the charger directly above battery being charged: gases from the battery will corrode and damage the

charger.

 Never allow battery acid to drip on to the charger when reading specific gravity or filling battery.
 Do not operate the charger in a closed-in area or restrict ventilation in any way.
 The battery charger should be connected to a grounded, metal, permanent wiring system; or an equipment–grounding

conductor should be run with circuit conductors not connected to equipment-grounding terminal on the battery charger.

 Connections to the battery charger should comply with all local codes and ordinances.
 G150, G300 & G600 – these battery chargers should be installed so that they are not likely to be contacted by people.

 EG150, EG300 & EG600 – the AC wiring should be independent of the DC and alarm wiring. Use 2x 2.5mm (total wire

Ø=5mm²) or larger wire for DC (charger to battery) leads. Use 2.5mm² or larger for input and ground connections.

For safe and correct use of the charger, follow the following steps. Should you have any problems or the unit does not
function as expected, consult our troubleshooting guide at the end of these instructions.

 Visually inspect unit for any signs of damage, caused by transport or storage.
 Mount the charger as outlined above, paying attention to ambient temperature.
 Ensure the mains AC supply is isolated, and ensure the correct rated input voltage before connection.
 Ensure the charger is earthed at the marked earth stud.
 Check batteries in accordance with the manufacturer’s guidelines.
 Check that the charger is correct for battery type and voltage.
 Connect the charger to the batteries, observing correct polarity and ensuring a secure and tight connection.
 Switch on charger at the mains AC supply.

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BEFORE BEGINNING INSTALLATION OF THIS PRODUCT

Disconnect all electrical power to the charger
Make sure the charger cannot operate during installation
Follow all safety warnings of the battery manufacturer
Read and follow all installation instructions

WARNING

WARNING: Guardian battery chargers contain
no user serviceable parts, and should be
returned to the supplier in the event of failure.

No attempt should be made to repair the
charger. Any attempt to do so may invalidate
warranties, cause damage to the charger and
equipment, and result in serious personal injury.

GENERAL INFORMATION

Please read the following before installing. A visual inspection of this product for damage during shipping is
recommended before installation. It is your responsibility to ensure that qualified mechanical and electrical
technicians install this product. Failure to follow the recommended installation instructions will invalidate the
product warranty. If in doubt, please contact your local Computronic representative.

Product specification

power supply:

operating voltages
operating frequency

110 – 120 VAC ±6% or

230 VAC ±10% (specify)

50 or 60 Hz (specify)

DC charge output:

nominal voltage

12 or 24 V DC

float / boost voltages

see table below

maximum current limit:
(E)G150-12V, (E)G300-24V
(E)G300-12V, (E)G600-24V

10 A
20 A

voltage ripple

< 1%

alarm outputs:

charge fail, low volts &
high volts relays

SPDT volt free contacts

contact rating

1A @ 30 V DC (resistive load)

general:

operating temperature

-10 to +55°C

dimensions

see ‘dimensions/assembly’ overleaf

weight

see ‘dimensions/assembly’ overleaf

EMC emission / immunity

EN61000-6-4 / EN61000-6-2

Output calibration

Battery type

float volts

(V DC)

boost volts

(V DC)

12V

Vented lead acid (6 cells)

13.5

14.1

Calcium-Calcium (6 cells)

13.8

15.6

VRLA, AGM (6 cells)

13.5

14.4

VRLA, Gel (6 cells)

13.5

13.8

NiCd (10 cells)

14.1

14.5

24V

Vented Lead acid (12 cells)

27.0

28.2

Calcium-Calcium (12 cells)

27.6

31.2

VRLA, AGM (12 cells)

27.0

28.8

VRLA, Gel (12 cells)

27.0

27.6

NiCd (18 cells)

25.6

26.1

NiCd (20 cells)

28.2

29.0

Note: Calibration figures at 20 deg C. Output voltage automatically
decreases by 3mV per cell per 1°C increase in temperature.

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Description & operation

The Guardian range provides automatic, current limited
and voltage controlled charging of vented lead acid, sealed
lead acid or NiCd batteries. The units may be
used in a wide range of industrial charging applications,
including standby engines, pumps and generators.

Each charger consists of a transformer, rectifier and
thyristor control circuit. The Guardian range is available as
either an open frame module for mounting in an enclosed
panel, or as a wall-mounted enclosure with DC charge
ammeter and voltmeter. (Note: In the event of no AC supply

to the charger, the voltmeter displays the DC voltage of the
battery or connected DC equipment.)

Electrical connection of the AC supply, battery and
(boost/alarm) control circuits is via spring-clamp terminals.

(For more information on these terminals, see Computronic
Controls Product Change Ref: CCL PC Release 1 – April

2003)

Float charge operation

In normal charging mode, the Guardian maintains the
battery at a pre-calibrated float voltage (see table right),
while supplying any additional DC load up to the specified
current limit (see Specification right).

When fully charged, a battery will only accept the charge
required to replace internal losses (approx. 1mA per AH of
battery). E.g. for a system with a 1 Amp standing load and a
fully charged 50 AH lead acid battery, Guardian will typically
supply 1.05 Amps.

Auto boost (equalising) operation

Auto boost operation gives a temporary increase in output
voltage (see table right), equalising the charge between
cells and maximising battery capacity and service life.
Once the batteries have reached the boost voltage level,
Guardian automatically reverts to its normal float charge
mode, preventing battery over-charge and gassing.

Auto boost is triggered automatically when the battery falls
below a preset voltage. An Auto Boost cycle can also be
manually initiated (regardless of battery voltage) by linking
two ‘boost’ terminals, e.g. via a panel switch or push-button.

enabled, output voltage decreases as ambient temperature
increases at a rate of 3mV/°C/cell (see calibration table
above for figures at 20°C).

Alarm outputs

Guardian provides 3 x NFPA110 compliant alarm relay
outputs: battery low volts and battery high volts (each with a
120 sec delay), and charge fail.

Warranty and servicing

Guardian chargers are supplied with a 2 year warranty on
parts and workmanship.

Temperature compensation

For both lead acid and NiCd batteries, the optimum charge
voltage varies with ambient temperature. On all Guardian
models, circuit board links allow output compensation to be
disabled, or enabled with an on-board temperature sensor,
or enabled with a remote sensor (RTC option, with 3 metre
lead for mounting on or near the battery). With this feature

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