G.T.Power A620 User manual

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Microprocessor controlled high-performance rapid charger/discharger
with integrated balancer / temperature sensor
operating manual
G.T. POWER A620

Contents
15
8. NiMH/NiCd battery program
2 Special features
1
4
2
4
8
9
11
11
12
13
13
14
14
3. Exterior of the unit
4. Warnings and safety notes
5. Program flow chart
6. Initial Parameter set up
7. Lithium battery(Lilo/LiPo/LiFe)program
7.1 Charging Lithium Battery
7.2 Charging Lithium battery at balance mode
7.4 'STORAGE' control Lithium battery
7.5 Discharging Lithium battery
7.6 Voltage balancing and monitoring during the discharge
7.3 'FAST' charging Lithium battery
1. Specifications

17
17
17
18
19
20
21
23
9. Pb( lead-sulphuric acid) battery program
10. Save Data Program
11. Load Data Program
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13. Warning and error messages
14. Warranty and service
9.1 Charging Pb battery
9.2 Discharging Pb battery
15
16
16
8.1 Charging NiCd/NiMH battery
8.2 Discharging NiCd/NiMH battery
8.3 Charge-to-discharge & discharge-to-charge cycle NiMH/NiCd battery

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1. Specifications
Input voltage range: 11.0 – 18.0Volt
Charge current range: 0.1 – 20.0A
Discharge current range: 0.1 – 5.0A
Maximum charge power capacity: 400W @ input voltage >15V
Maximum discharge power capacity: 25W
Current drain for balancing Li-po: 200mAh/cell
Lithium (LiPo/LiIo/LiFe) battery cell count: 1 – 6 series
NiCd/NiMH battery cell count: 1 – 18 series
Pb battery voltage: 2 –20V
Battery setup memories: 10
Intelligent temperature control: Yes
Weight: 820g
Dimensions : 152X145X57mm

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2. Special features
Operating software
Every operating program in the unit is controlled with mutual links and communications to prevent every possible error, so it
introduces the maximum safety, such as input voltage warning, reverse polarity protection and Lithium cell-count input error warning.
High-power and high-performance circuit
It employs the circuit that has maximum output power of 400Watts. As a result it can charge or discharge up to 18 cells of NiCd/NiMH
and 6 series of Lithium batteries with maximum current of 20A. Furthermore the cooling system is so efficient that can hold such a power
without any trouble of running the CPU or the operating program.
Individual voltage balancer for Lithium batteries inside
It has an individual-cell-voltage balancer inside.This does not require any extra balancer separately when charging Lithium
batteries(Lilo/LiPO/LiFe) for cell voltage balancing.
Balance individual cells on discharge
It also can monitor and balance individual cells of the Lithium battery pack during the discharge process. If the voltage of any one cell
varies abnormally, the process will be stopped with the error message.
Accept various types of Lithium battery
It can accept three types of Lithium batterles- Lilo, LiPo and LiFe. They have different characteristics by their chemistry. You can
select any one of them that you are going to process before the job. For their specifications, refer ‘Warnings and safety notes’ section.
Lithium battery 'Fast' and 'Storage' mode
You can charge Lithium battery for special purposes. 'Fast' charge reduces the charging time of Lithium battery and 'Storage' mode
controls the final voltage of the battery to be suit for long time storage.
Maximum safety
Delta-peak sensitivity: The automatic charge termination program works on the principle of the Delta-peak voltage
detection.(NiCd/NiMH)

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Auto-charge current limit: When charging NiCd or NiMH at 'AUTO' current mode, you can set the upper limit of change current to
avoid from high current charging. This is very useful when charging the low impedance and small capacity NiMH battery in 'AUTO' mode.
Capacity limit: The changing capacity always calculated by multiple of the charging current and time. If the charging capacity exceeds
the limit the process will be terminated automatically when you set the maximum value.
Temperature limit: The temperature of the battery on charging will rise by its internal chemical reaction. If you set the limit of
temperature the process will be expired forcibly when the limit has reached.
Processing time limit: you can also restrain the maximum process time to prevent from any possible defect.
Input power monitor: To protect the car battery using as input power from being damaged the voltage of it always monitored. If it
dorps below the lower limit the process will be ended automatically.
Automatic cooling fan: The electric cooling fan comes into action automatically only when the internal temperature of the unit is
raised.
Data store/load
For users convenience it can store maximum 10 data of different batteries. You can establish the data contains program setting of the
battery to charge or discharge continually. These data can be called out at any time you need and the process can be executed without
program setting.
Cyclic charging/discharging
Perform 1 to 5 cycles of charge>discharge or discharge>charge continually for battery refreshing and balancing.

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3. Exterior of the unit
4. Warnings and safety notes
•Never leave the charge unsupervised when it is connected to its power supply. If any malfunction is observed immediately terminate
the process and refer to the operation manual.
•Keep away the unit from dust, damp, rain, heat direct sunshine and vibration. Do not dorp it.
•This unit and the battery to charge or discharge should be set up on a head-resistant, non-inflammable and non-conductive surface.
Never place them on a car seat, carpet or similar. Keep all the inflammable volatile materials well away from operating area.
•Be sure to understand the information of the battery to be charged or discharged accurately. If the program is set up incorrectly the
battery can severely be damaged. Especially Lithium battery can cause a fire or an explosion by over-charging.
•To avoid short-circuits between the charge lead, always connect the charge cable to the unit first and only then to the battery to be
Cooling fan
Balance socket
Cooling fan
Output port
Temperature
sensor port

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voltage level:1.2V/cell
allowable fast charge current:1C~2C depends on the performance of cell
discharge voltage cut off level :0.85V/cell(NiCd), 1.0V/cell(NiMH)
voltage level:3.6V/cell
max.charge voltage:4.1V/cell
allowable fast charge current: 1C or less
min.discharge voltage cut off level:2.5V/cell or higher
voltage level:3.7V/cell
max.charge voltage:4.2V/cell
discharge voltage cut off level:3.0V/cell or higher
voltage level:3.3V/cell
max.charge voltage:3.6V/cell
allowable fast charge current: 4C or less(e.g. A123M1)
discharge voltage cut off level:2.0V/cell or higher
voltage level:2.0V/cell (Lead-acid)
max.charge voltage:2.46V/cell
allowable fast charge current:0.4C or less
discharge voltage cut off level:1.50V/cell or higher
NiCd/NiMH
Lilo
LiPo
Life
Pb
charged or discharged. Reverse the hsequence when disconnecting.
• Do not connect more than one battery pack to the charge lead at any one time.
• Do not attempt to disassemble the battery pack arbitrarily.
- Battery pack, which consists of different types of cell (including different manufacturers).
- Battery, which is already fully charged or just slightly discharged.
- Non-rechargeable batteries (Explosion hazard).

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- Batteries that require a different charge technique from NiCd, NiMH, Lilo, LiPo, LiFe or Pb.
- Faulty or damaged battery.
- Battery fitted with an integral charge circuit or a protection circuit.
- Batteries installed in a device, or which are electrically linked to other components.
- Batteries that are not expressly stated by the manufacturer to be suitable for the currents the charger delivers during the charge process.
• Please bear in mind of checking the following point before charge operation.
- Did you select the appropriate program, which are suitable for the type of battery?
- Did you set up adequate current for charging or discharging?
- Lithium battery pack can be composed with parallel and series circuits mixed. You have to check the composition of the battery pack
carefully before charging.
- Are all connections firm and safe, or is there an intermittent contact at any point in the circuit?
• Charging
A specific quantity of electrical energy is fed into the battery during charge process. The charge quantity is calculated by multiplying
charge current by charge time. The maximum permissible charge current varies according to the battery type or its performance, and
can be found in the information provided by the battery manufacturer. It is only allowed to charge batteries at rates higher than the
standard charge current if they are expressly stated to be capable of quick-charge.
- Connect the battery to charge to output terminal of the charger using suitable charge lead. They are red, positive(+)and black,
negative(-).Since the charger cannot detect the difference between the internal resistance of the battery pack, cable resistance and
connector transfer resistance, the first requirement if the charger to work properly is that the charge lead should be of adequate
conductor cross-section. And also high-quality connectors (normally gold-contact type) must be fitted to both ends.
- Refer to the information provided by the battery manufacturer regarding charging methods, and verify the recommended charge
current and charge time.Especially for Lithium batteries, you have to follow the charge instruction provided by the manufacturer
strictly.
- Do not attempt to disassemble the battery pack arbitrarily.
- You have to pay attention to verify the capacity and the voltage of the Lithium battery pack. It may be composed of parallel and
series connection mixed. In parallel link the capacity of the battery pack is multiplied by the number of cells but the voltage remains
same. That kind of voltage imbalance causes a fire or explosion during charge process. We recommend you compose the Lithium
battery pack in series only.

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• Discharge
The typical purpose of discharge is to determine the residual capacity of the battery, or to lower the voltage of battery to a defined
level. When you discharge the battery you also have to pay attention on the process same as charging. To avoid the battery becoming
deep-discharged, set the final discharge voltage correctly. Lithium batteries should not be deep-discharged to lower than the minimum
voltage, as this leads to a rapid loss of capacity or a total failure. Generally, you do not need to discharge Lithium battery voluntarily.
- Some rechargeable batteries are said to have a memory effect. If they are partly used and recharged before the whole charge
is drawn out, they‘remember’ this and next time will only use that part of their capacity. This is a ‘memory effect’. NiCd and NiMH
batteries are said to suffer from memory effect. They prefer complete cycles; fully charge then use until empty, do not recharge before
storage-allow them to self-discharge during storage. NiMH batteries have less memory effect than NiCd.
- The Lithium battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided if possible. Instead,
charge the battery more often or use a larger battery.
- The brand-new NiCd battery pack is partially useful with its capacity until it has beeen subjected to 10 or more charge cycles in any
case. The cyclic process of charge and discharge will lead to optimise the capacity of battery pack.
Those warnings and safety notes are particularly important. Please follow the instructions for a maximum
safety; otherwise the charger and the battery can be damaged violently. And also it can cause a fire to
injure a human body or to lose the property.

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5. Program flow chart
Key Beep
Buzzer
Input Power
Low Cut-Off
Back-Light
brightness
PROGRAM SELECT
LIXX BATT
PROGRAM SELECT
NiMH BATT
PROGRAM SELECT
Nicd BATT
USERSET
PROGRAM
PROGRAM SELECT
Pb BATT
PROGRAM SELECT
SAVE DAT A
PROGRAM SELECT
LOADDATA
NiMH CHARGE
'Aut' / 'Man'
N
icd
CHARGE
'Aut' / 'Man'
Capacity Cut-Off
Safety Timer
LIXX V. Type
LIXX DISCHARGE
NiMH DISCHARGE
N
icd DISCHARGE
LiPo/Lilo/LiFe
CHK Time
NiMH/Nicd/Pb
Trickle charge
NiMH Sensitivity
D. Peak
Waste Time
CHG>DCHG
Nicd Sensitivity
D. Peak
Temp Cut-Off
Pb DISCHARGE
NiMH CYCLE
Nicd CYCLE
Pb
CHARGE
SAVE DATA
LOAD DATA
LIXX CHARGE LIXX BALANCE
LIXX FAST CHG LIXX STORAGE
Start
Enter
Start
Enter
Start
Enter
Start
Enter
Start
Enter
Start
Enter
Start
Enter
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
INC
DEC
Batt type
stop
Batt type
stop
Batt type
stop
Batt type
stop
Batt type
stop
Batt type
stop

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6. Initial parameter set up
When you are willing to alter the parameter value in the program, press Start/Enter key to make it blink then change the value with
INC or DEC key. The value will be stored by pressing Start/Enter key once.
This informs you of its designation.
The screen displays the nominal voltage of Lithium battery. There are three kinds of Lithium
battery; LiFe(3.3V),Lilo(3.6V) or LiPo(3.7V). This is very important so you have to check the battery
carefully and set it up correctly. If it is different from correct value the battery can explode during
charge process.
It recognise the cell count of Lithium battery automatically at the beginning of charge or discharge
process to avoid from erroneous setting by user. But deeply discharged battery can be perceived
incorrectly. To prevent the error, you can set the time term to verify the cell count by the processor.
Normally, 10 minutes are enough to perceive the cell count correctly. For the battery of larger
capacity, you may extend the time term. But if you set the time term too long for the battery of
smaller capacity, the charge or discharge process can be finished within the time term with the
erroneous cell count. This may cause the fatal result. If the processor recognises the cell count
incorrectly at the beginning of charge or discharge process, you may extend the time. Otherwise,
you had better use with the default value.
This shows the trigger voltage for automatic charge termination of NiMH and NiCd battery. The
effective value ranges from 5 to 20mV per cell .if the trigger voltage is set higher, there is a danger
of overcharging the battery; if it is set lower, there is a possibility of premature termination. Please
refer the technical specification of the battery.(NiCd default:12mV/cell, NiMH default:7mV/cell)
PROGRAMUSER SET

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An optional feature using temperature probe contacting the surface of battery, the temperature
cut-off can be on or off. If it is on, set the maximum temperature at which the charger should allow
battery to reach during charge, Once a battery reaches this temperature during charge, the process
will be terminated to protect the battery.
The battery is on the cyclic process of charge and discharge can often become warm after charge
or discharge period. The program can insert a time delay to occur after each charge and discharge
process to allow the battery adequate time to cool down before being subjected to the next
process. The value ranges from 1 to 60 minutes.
You can set the trickle charge mode on or off.If it is on, the charge will automatically supply the
trickle charge current to achieve the full charge without overheating the battery after fast charge
has been terminated.
When you start a charge process, the integral safety timer automatically starts running at the
same time. This is programmed to prevent overcharge the battery if it proves to be faulty, or if the
termination circuit cannot detect the battery full. The value for the safety timer should be generous
enough to allow a full charge of the battery .
This program sets the maximum charge capacity that will be supplied to the battery during charge.
If the delta-pack voltage is not detected nor the safety timer expired by any reason, this feature will
automatically stop the process at the selected capacity value.
The beep sounds at every time pressing the buttons to confirm your action. The beep or melody
sounded at various times during operation to alert different mode changes. These audible sounds
can be on or off.

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This program monitors the voltage of input battery. If the voltage drops below the value you set the
operation forcibly terminated to protect the input battery.
You can adjust the brightness of LCD screen at the charger.
The left side of the first line shows the type of battery you select at the users setting. The value on
the left side of second line sets a charge current and the value on the right side of second line sets
the voltage of the battery pack.
After setting the current and voltage press Start/Enterkey for more than 3 seconds to start the
process.
(Charge current:0.1~20.0A,Voltage:1~6 series)
7. Lithium battery(Lilo/LiPo/LiFe)program
These programs are only suitable for charging and discharging Lithium batteries with a nominal voltage of 3.3V, 3.6V and 3.7V per
cell. These batteries need to adopt different charge technique is termed a constant voltage(CV) and constant current(CC) method. The
charge current varies according to the battery capacity and performance. The final voltage of charge process is also very important; it
should be precisely matched with the charade voltage of the battery. They are 4.2V for LiPo, 4.1V for Lilo, and 3.6 V for LiFe. The charge
current and nominal voltage as for cell count set on the charge program must always be correct for the battery to be charged.
When you are willing to alter the parameter value in the program, press Start/Enter key to make it blink then change the value with
INC or DEC key. The value will be stored by pressing Start/Enter key once.
7.1 Charging Lithium Battery

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This shows the number of cells you set up and the processor detects. ' R:' shows the number of
cells found by the charger and ' S:' is the number of cells selected by you at the previous screen.
If both numbers are identical you can start charging by press Start/Enter button. If not, press Batt
Type/Stop button to go back to previous screen. Then carefully check the number of cells of the
battery pack to charge again.
The screen shows the present situation during charge process. To stop charging press Batt Type/
Stop key once.
7.2 Charging Lithium battery at balance mode
This is for balancing the voltages of Lithium batteries of the battery parkto be charged. The battery pack to be charged should
be connected tothe suitable balance port at the right side of the charger. And also, you need to connect the battery output plug to
the output of charger.
In this mode, the charging process will be different from ordinary charging mode. The internal processor of the charger will monitor
the voltages of each cell of the battery pack and controls charging current that is feeding to each cell to normalise the voltage.
The value on the left side of second line sets a charge current and the value on the right side of
second line sets the voltage of the battery pack.
After setting the current and voltage press Start/ Enterkey for more than 3 seconds to start the
process.
(Charge current:0.1~20.0A, Volatge:1~6 series)
This shows the number of cells you set up and the processor detects.' R: ' shows the number of
cells found by the charger and ' S:' is the number of cells selected by you at the previous screen. If
both numbers are identical you can start charging by press Start /Enter button. If not, press Batt
type/Stop button to go back to previous screen. Then carefully check the number of cells of the
battery pack to charge again.
Balance

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The screen shows the present situation during charge process. To stop charging press Batt type/
Stop key once.
7.3 'FAST' charging Lithium battery
The charging current is getting smaller as the process goes to the near end term of Lithium battery chaging. To finish charging
process earlier, this program eliminate certain term of CV process. Actually, the charging current will goes to 1/5 from the initial value to
end the process while the normal chaging goes to 1/10 during CV term. The charging capacity may be a bit smaller than normal charging
but the process time will be reduced.
You can set up the charging current and the voltage of the battery pack being charged. As you
press Start/ Enterbutton the voltage confirmation will be displayed. And then, if you confirm the
voltage and current, press Start/ Enter button again to start charging.
This shows the present state of 'FAST' charging. To stop charging arbitrary, press Batt type/Stop
key once.
7.4 'STORAGE' control Lithium battery
This is for charging or discharging Lithium battery not to be used for the time being. The program will determine to charge or
discharge the battery to the certain voltage depending on the voltage of the battery at its initial stage. They are different from the type of
the battery, 3.75V for Lilo, 3.85V for LiPo and 3.3V for LiFe per cell. If the voltage of battery at its initial stage is over the voltage level to
storage, the program will start to discharge.

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You can set up the current and the voltage of the battery pack to be charged. The current will be
used for charge or discharge the battery to reach the ' storage ' level of voltage.
The screen shows the present situation during charge process. To stop charging press Batt type/
Stop key once.
7.5 Discharging Lithium battery
The value of discharge current on the left side of screen may not exceed 1C for a maximum safety
and the final voltage on the right should not be under the voltage level that is recommended by the
battery manufacturer to avoid deep discharging.
To start to discharge, press Start/ Enter key for more than 3 seconds.
(Discharge current:0.1~5.0A)
This shows the present state of discharge. To stop discharging press Batt type/Stop key once.
7.6 Voltage balancing and monitoring during the discharge
The processor monitors the voltage of individual cells during 'storage-mode' and 'discharge' of Lithium battery pack. It tries to
normalise the voltages to be equal. For this feature, the individual plug of the battry pack should be connected to the individual
port of the charger.
If the voltage of any one or more cells varies abnormally during the procedure, It terminates the process forcibly with the error
massage. If this happens, the battery pack contains the bad cell, or the bad connection of the cable plug. You can easily know
which one cell is bad by pressing INC button at time of showing the error message

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The processor found that the voltage of one of the cell in the Lithium battery pack is too low.
In this case, the 4th cell is bad. If there happens the connection-break of th cable or plug, the
voltage value may show zero.
8. NiMH/NiCd batter y program
These programs are for charging or discharging NiMH (Nickel-Metal-Hydride) or NiCd (Nickel-Cadmium) battery commonly
used for R/C model aplications. To alter the value at the display, press Start/Enterkey to make it blink then change the value
using INC or DEC key.The value will be stored by pressing Start/Enterkey once.
To start the process, press Start/ Enterbutton for more than 3 seconds.
8.1 Charging NiCd/NiMH battery
This program simply charge the battery using the current you set. In 'Aut' mode, you need to set
the upper limit of charge current to avoid from higher feeding current that may damage the battery.
Because some batteries of low impedance and small capacity can lead to the higher charge current
by the processor at automatic charge mode. But in 'Man' mode, it will charge the battery with the
charge current you set at the display. Each mode can be switched by pressing INC and DEC button
simultaneously when the current field is blinking.
The screen displays the current state of charging . To stop the process, press Batt type/Stop key once.
The audible sound indicates you the end of process.

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8.2 Discharging NiCd/NiMH battery
8.3 Charge-to-discharge & discharge-to-charge cycle NiMH/NiCd battery
Set discharge current on the left and final voltage on the right. The discharge current ranges
from 0.1 to 5.0A and the final voltage ranges from 0.1 to 25.0V). To start the process, press
Start /Enterkey more than 3 seconds.
The screen displays the current state of discharge. You can alter the discharge current by
pressing Start/Enterkey during the process. Once you change the current value, store it by
pressing Start/Enterbutton again.
To stop discharging press Batt type/Stop key once. The audible sound indicated you at the
end of process.
Set the sequence on the left and the number of cycle on the right. You can use this function
for balancing, refreshing and break-in the battery. To avoid rising temperture of the battery,
there will a brief cool-off period that already fixed at 'User setting' after each charge and
discharge process. The cycling number ranges from 1 to 5.
To stop the process, pressBatt type/Stop key once.
You can change the discharge or charge current by pressing Start/Enterkey once during the
process. The audible sound indicates you the end of process.
At the end of the process, you can see charged or discharged electric capacities of the battery
at each cyclic process.
By pressing INC or DEC button, the screen shows the result of each cycle in order.

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9. Pb( lead-sulphuric acid) battery program
This is programmed for charging Pb( lead-sulphuric acid) battery with nominal voltage from 2 to 20V. Pb batteries are totally
different from NiCd or NiMH batteries. They can only deliver relatievely lower current compare to their capacity, and similar
restrictions definitely apply to charge. So the optimal charge current will be 1/10 of the capacity. Pb batteries must not be charged
rapidly. Always follow the instruction is supplied by the manufacturer of battery.
When you are willing to alter the parameter value in the program, press Start/Enter key to make it blink then change the value
with INC or DEC key. The value will be stored by pressing Start/Enter key once.
9.1 Charging Pb battery
Set up the charge current on the left and the nominal voltage of the battery on the right. The
charge current ranges from 0.1 to 20.0A and the voltage should be matched with the battery
being charged.
Start the charge process by pressing Start/Enter key for more than 3 seconds.
The screen displays the state of charging process. To stop charging forcibly, press Batt type/
Stop key once.
The audible sound indicates you at the end of process.
Set discharge current on the left and final voltage on the right. The discharge current ranges
from 0.1 to 5.0A.
To start the process, press Start/Enter key for more than 3 seconds.
9.2 Discharging Pb battery