Smartgen BAC4812-KP User manual

BAC4812-KP
BATTERY CHARGER
USER MANUAL

Chinese trademark
English trademark
SmartGen —make your generator smart
SmartGen Technology Co., Ltd.
No.28 Jinsuo Road, Zhengzhou, Henan Province, China
Tel: [phone]
[phone](overseas)
Fax: [phone]
Email: [e-mail]
Web: www.smartgen.com.cn
www.smartgen.cn
All rights reserved. No part of this publication may be reproduced in any material form (including
photocopying or storing in any medium by electronic means or other) without the written permission
of the copyright holder.
Applications for the copyright holder’s written permission to reproduce any part of this publication
should be addressed to Smartgen Technology at the address above.
Any reference to trademarked product names used within this publication is owned by their
respective companies.
SmartGen Technology reserves the right to change the contents of this document without prior
notice.
Table 1 Software Version
Date
Version
Note
2015-03-10
1.0
Original release.
2016-01-18
1.1
Modify the thickness of BAC4812-KP to 54mm.
2017-11-10
1.2
Update “CASE DIMENSIONS”
2021-12-25
1.3
Add DC voltage range.
2021-12-29
1.4
Change mask and modify case dimension diagram as line
drawing.
2022-01-18
1.5
Modify insulating property.
2022-06-16
1.6
Update the Logo of SmartGen.

BAC4812-KP Battery Charger User Manual Page 3 of 7
CONTENT
1. OVERVIEW....................................................................................................................................................4
2. PERFORMANCE AND CHARACTERISTICS.................................................................................................4
3. CHARGING PRINCIPLE................................................................................................................................4
4. SPECIFICATION ...........................................................................................................................................5
5. VOLTAGE/CURRENT REGULATION............................................................................................................5
5.1. VOLTAGE REGULATION.................................................................................................................. 5
5.2. CURRENT REGULATION ................................................................................................................. 5
6. OPERATION..................................................................................................................................................6
6.1. MASK DESCRIPTION....................................................................................................................... 6
6.2. COMMON FAULTS AND TROUBLESHOOTING.............................................................................. 6
6.2.1. FAULT DIAGNOSIS ............................................................................................................ 6
6.2.2. PROCEDURES OF CHANGING FUSE.................................................................................. 6
7. CASE DIMENSIONS .....................................................................................................................................7

BAC4812-KP Battery Charger User Manual Page 4 of 7
1. OVERVIEW
Fit with up-to-date power supply device, float charger BAC4812-KP is specially designed for meet
the charging characteristics of the lead-acid engine starter batteries and can be used for long-term float
charging of 12V lead-acid batteries.
2. PERFORMANCE AND CHARACTERISTICS
1) Switch power supply structure, wide DC input voltage range, small size, light weight, high efficiency;
2) Automatic two-stage charging process (first constant current, then constant voltage) carried out
according to storage battery charging characteristics to prevent overcharging and significantly
prolong battery lifetime;
3) Built-in current protective circuit for short-circuit protection and reverse connection protection;
4) Both charging voltage and current value can be regulated by potentiometer on the spot;
5) Suitable for 12V storage battery and the rated current is 3A;
6) LED display: Power indication (Green light) and charging indication (Red light).
3. CHARGING PRINCIPLE
Fig.1 Charging Principle
Charging is performed according to the battery charging characteristics using two-stage method.
The first-stage charging mode is “constant current”which means that when the battery terminal voltage
falls below the pre-set value, charging current will be constant. The second-stage charging mode is
“float charging”, when the battery terminal voltage exceeds the pre-set value, charging current will
decrease with the rising of terminal voltage until the pre-set current value is reached; then chargers
automatically return to float mode. As soon as charging current value falls below 0.5A and the constant
voltage value is reached, the battery is basically charged (charging indicator will extinguish). After that
charging current will only neutralize the battery self discharge. Even long-term charging cannot harm
the battery, as charger can keep the battery fully charged and so guarantee long lifetime of the battery.

BAC4812-KP Battery Charger User Manual Page 5 of 7
4. SPECIFICATION
Table 2 Technical Parameters
Items
Contents
Parameters
Input
Characteristics
Rated Input Voltage
DC48V
Input Voltage Range
DC36V~DC72V
Rated Input Current
1A
No-load Power
Consumption
<3W
Output
Characteristics
No-load Output Voltage
13.8V, (Error ±1%)
Rated Charging Current
3A, (Error ±2%)
Insulating Property
Insulating Resistance
Between input and output, input and shell, output
and shell are: DC500V 1min RL≥10MΩ
Insulating Voltage
Between input and output, input and shell, output
and shell are: DC500V 1min; Leakage current:
IL≤3.5mA
Working Condition
Working Temperature
(-30~+55)°C
Working Humidity
20%RH~93%RH (No condensation)
Storage Condition
Storage Temperature
(-40~+85)°C
Shape Structure
Weight
0.66kg
Dimension
143mm*96mm*55mm (length*width*height)
5. VOLTAGE/CURRENT REGULATION
5.1. VOLTAGE REGULATION
If adjust voltage on-site, battery needs to be disconnected with battery charger, and then adjust the
voltage potentiometer (VOLT) to the appropriate value while measuring the charger output voltage.
5.2. CURRENT REGULATION
After connecting output port to the storage battery, measuring charging current under 12.5V
charging voltage, and then adjust the current potentiometer (AMP) to the appropriate value. Current
also can be estimated according to the scale of the current potentiometer.

BAC4812-KP Battery Charger User Manual Page 6 of 7
6. OPERATION
6.1. MASK DESCRIPTION
Fig.2 BAC4812-KP Mask
─Connect terminals IN+ and IN- to DC48V using BVR 1mm2multi-strand copper line.
─Connect B+ and B- to battery positive and negative using BVR 1.5mm2multi-strand copper line.
─POWER: Power supply indicator, illuminates when the charger is operating normally.
─CHARGING: Charging indicator, illuminates when charging current exceeds 0.5A while extinguishes
when falls below 0.5A.
─VOLTS: charging voltage regulator potentiometer.
─AMP: charging current regulator potentiometer.
─FUSE: Output fuse; rated current: 6A; fuse will blow out when output connection is reversed (no
output voltage). It will work normally once correct connection and replace the fuse.
NOTE:
1) Because there is diode and current-limiting circuit inner the charger, it can be used together with charging generator,
and there is no need to disconnect the charger when cranking.
2) During genset is running, high current will cause voltage drop in charging line, so recommend separately connecting to
battery terminal to avoid disturbance on sampling precision.
6.2. COMMON FAULTS AND TROUBLESHOOTING
6.2.1. FAULT DIAGNOSIS
Output terminal of battery charger short circuit or battery reverse connection may blow the charger
output fuse. In that case, after connecting AC power supply, charger green LED lights on but output
terminal has no voltage, and then remove the output fuse tube to visually observe whether fuse is blown
or not, if condition permits, multimeter can be used to measure the fuse status.
a) If output terminal 6A fuse is blown, users only needs to change the same capacity fuse.
b) If output fuse isn’t blown or after the fuse is replaced, battery still doesn’t output, battery needs to
depot repair.
c) Fuse burn emergency method: using conductive metal wire short connects burnt fuse, and then
change the fuse later.
6.2.2. PROCEDURES OF CHANGING FUSE
a) Press hard towards inside with slotted screwdriver, screw counter-clockwise and then take out the
fuse. (improper operation or over tightening may damage the block).
b) Put a new fuse into the block, press with the slotted screwdriver and screw clockwise.

BAC4812-KP Battery Charger User Manual Page 7 of 7
7. CASE DIMENSIONS
Unit: mm
Fig.3 Case Dimensions
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