Studer VS-70, VS-120 User Manual
Accessories:
Remote control……………………………………. RCC-02/03
Temperature sensor…....…………………………. BTS-01
External auxiliary relay module...………………. ARM-02
VarioString
VS - 120
48V- 120A
VarioString
VS -70
48V- 70A
VarioString
MPPT solar charge controller
User manual
Studer Innotec SA 2018 V 2.2
4O9P
Studer Innotec SA
VarioString
2 V 2.2 User manual
Studer Innotec SA
VarioString
Contents
1 INTRODUCTION ................................................................................................................................... 5
2 GENERAL INFORMATION .................................................................................................................... 5
2.1 About this user manual ..................................................................................................................... 5
2.2 Important safety instructions ............................................................................................................ 6
2.3 Conventions ....................................................................................................................................... 6
2.4 Quality and warranty ........................................................................................................................ 7
2.4.1 Exclusion of warranty ................................................................................................................ 7
2.4.2 Exclusion of liability .................................................................................................................... 7
2.5 Warnings and guidelines .................................................................................................................. 8
3 MOUNTING AND INSTALLATION ......................................................................................................... 8
3.1 Storage ................................................................................................................................................ 8
3.2 Unpacking .......................................................................................................................................... 8
3.3 Mounting place ................................................................................................................................. 9
3.4 Fixing/Dimensions .............................................................................................................................. 9
3.4.1 VarioString VS-120 ..................................................................................................................... 9
3.4.2 VarioString VS-70 .................................................................................................................... 10
3.4.3 Assembling the cooling fan ECF-01 ..................................................................................... 10
4 WIRING .............................................................................................................................................. 11
4.1 Elements of the cable compartment .......................................................................................... 11
4.1.1 VarioString VS-70 ..................................................................................................................... 12
4.1.2 VarioString VS-120 ................................................................................................................... 13
4.2 Connecting the battery ................................................................................................................. 14
4.2.1 Precautions when using the batteries ................................................................................. 14
4.2.2 Connecting the battery ......................................................................................................... 15
4.2.3 Protection device of the battery .......................................................................................... 15
4.3 Photovoltaic generator (PV) ......................................................................................................... 16
4.3.1 Dimensioning ........................................................................................................................... 16
4.3.2 Serial connection (chain or string) of PV modules ............................................................ 17
4.3.3 Parallel connection of PV module strings ........................................................................... 18
4.3.4 Safe use of the photovoltaic modules ................................................................................ 19
4.3.5 Protection devices .................................................................................................................. 19
4.3.6 Cable cross-section and connection .................................................................................. 19
4.3.7 Parallel connection of several VarioString .......................................................................... 19
4.3.8 Extension of an existing installation ...................................................................................... 20
4.4 Earthing ............................................................................................................................................. 20
4.4.1 Detecting an earthing fault .................................................................................................. 20
4.5 Lightning protection ........................................................................................................................ 21
4.6 Connecting the communication cables ..................................................................................... 21
5 POWER-UP OF THE EQUIPMENT ........................................................................................................ 22
6 DISPLAY SYSTEM ................................................................................................................................ 23
6.1 The “SET” button (4) ......................................................................................................................... 23
6.2 “Night” standby indicator (1) ........................................................................................................ 23
6.3 “Charge” cycle indicator (2) ........................................................................................................ 23
6.4 “Error” indicator (3) ......................................................................................................................... 24
6.5 Charging current Indicator (5)-(6)-(7)-(8)-(9)-(10) ...................................................................... 24
7 BATTERY CHARGING PROCESS ........................................................................................................ 25
7.1 General points ................................................................................................................................. 25
7.2 Battery cycle .................................................................................................................................... 25
7.2.1 Bulk phase (1) .......................................................................................................................... 25
7.2.2 Absorption phase (2) .............................................................................................................. 25
7.2.3 Floating phase (4) ................................................................................................................... 25
7.2.4 Equalization phase (3) ............................................................................................................ 25
7.2.5 Temperature compensation ................................................................................................. 26
7.3 Default battery charge cycle (original settings) ........................................................................ 26
7.4 Recovery after deep discharge ................................................................................................... 26
8 REMOTE ENTRY (AVAILABLE AS FROM SOFTWARE VERSION 1.5.22) .............................................. 27
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VarioString
9 CONFIGURING THE VARIOSTRING(S) ............................................................................................... 27
9.1 Configuring the equipment by means of the internal DIP switches ........................................ 27
9.2 Displaying the equipment status using the remote control RCC-02/03 ................................. 29
9.2.1 Displaying the status of a single unit system ....................................................................... 29
9.2.2 Displaying the operating mode of the equipment (Info n° 15013,15014,15015) .......... 31
9.2.3 Displaying security errors (Info n° 15049) ............................................................................. 32
9.2.4 Displaying the values of a multi-unit system ....................................................................... 32
9.2.5 Displaying messages and event history .............................................................................. 32
9.3 Configuring the VarioString using the remote control RCC-02/03 .......................................... 33
9.3.1 The real time clock ................................................................................................................. 33
9.4 Description of the VarioString parameters .................................................................................. 33
9.4.1 Convention .............................................................................................................................. 33
9.4.2 Parameter access level ......................................................................................................... 34
9.4.3 Organisation of the VarioString configuration menu ........................................................ 34
9.4.4 Basic settings {14000} .............................................................................................................. 36
9.4.5 Battery management and cycle {14003} ........................................................................... 36
9.4.6 System {14037} ......................................................................................................................... 40
9.4.7 Auxiliary contacts 1 {14070} and 2 {14122} ......................................................................... 42
10 ACCESSORIES ................................................................................................................................... 46
10.1 Remote control and programming centre RCC-02/03 ............................................................. 46
10.2 Temperature sensor BTS-01 ............................................................................................................. 47
10.2.1 Connecting the temperature sensor (BTS-01) .................................................................... 47
10.3 Auxiliary relay module ARM-02 ...................................................................................................... 48
10.4 Parallel connection cable ............................................................................................................. 48
11 EQUIPMENTS COMPATIBLE WITH THE VARIOSTRING ....................................................................... 48
11.1 Xtender inverter/chargers .............................................................................................................. 48
11.2 Battery status processor BSP- 500/1200 ........................................................................................ 48
11.3 Communication module Xcom-232i ............................................................................................ 49
11.4 Communication sets Xcom-LAN/-GSM ........................................................................................ 49
11.5 Communication module Xcom-SMS ............................................................................................ 49
11.6 Multi-protocol communication module Xcom-CAN ................................................................. 49
12 WIRING EXAMPLES ............................................................................................................................ 50
12.1 VarioString + RCC-02 ....................................................................................................................... 50
12.2 Comments on the wiring examples 12.1 ..................................................................................... 50
12.3 VarioString VS-70 + RCC-02 ............................................................................................................ 51
12.4 Comments on the wiring examples 11.3 ..................................................................................... 51
13 MAINTENANCE OF THE INSTALLATION ............................................................................................. 52
14 PRODUCT RECYCLING ...................................................................................................................... 52
15 EU DECLARATION OF CONFORMITY ................................................................................................ 52
16 TROUBLE-SHOOTING ......................................................................................................................... 53
17 PARAMETER LIST ................................................................................................................................ 54
18 TECHNICAL DATA .............................................................................................................................. 58
18.1 General specifications .................................................................................................................... 58
18.2 Input (PV generator) ....................................................................................................................... 58
18.3 Output (battery) .............................................................................................................................. 58
18.4 Environment...................................................................................................................................... 59
18.5 Protection ......................................................................................................................................... 59
18.6 Communication .............................................................................................................................. 59
18.7 Compliance ..................................................................................................................................... 59
19 INDEX OF PARAMETERS .................................................................................................................... 60
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This manual is an integral part of the equipment and must be available for the operator
and/or the installer at all times. Always keep it close to the installation.
VarioString
1 INTRODUCTION
Congratulations! You are about to install and use a device from the VarioString range. You have
chosen high-tech equipment that will play a central role in the energy production of your solar
electrical installation. The VarioString has been designed to work as a solar battery charger; its
advanced and completely configurable functionalities will guarantee a perfect functioning of your
energy system.
When the VarioString is connected to batteries and photovoltaic panels, it automatically recharges
batteries in an optimum way with all the available solar power. The VarioString VS-120 can be
connected to two strings of PV modules in different configurations (series, parallel, or independent).
This configuration flexibility allows the user to optimise their installation. The accuracy of the Maximum
Power Point Tracking (MPPT) algorithm, the high output and low internal consumption ensure an
optimal valorisation of the energy produced by the PV modules.
The charge profile may be set freely according to the battery type or the operation mode. The
charging voltage is corrected depending on the temperature thanks to the optional external sensor
BTS-01.
The control, display and programming unit RCC-02/03 (optional) allows an optimal setup of the
system and guarantees the user a permanent control over all important parameters for the
installation with a clear display interface. Moreover, it allows recording the system data in order to
analyse later its functioning (data logging).
The parallel operation of several chargers is possible and offers modularity and flexibility enabling an
optimum dimensioning of your system according to your energy requirements.
The VarioString operates as an independent device but is also designed to be included into a Studer
energy system together with the Xtender inverters/chargers, the BSP battery monitor, the control,
display and programming unit RCC-02/03 and all Xcom communication modules. Working together,
these different devices have a synchronised behaviour for a better management of the battery and
of the solar resource.
Please read this manual carefully to ensure the perfect start up and operation of your system. It
contains all necessary information regarding the operation of the VarioString charger. The installation
of such a system requires special expertise and may only be carried out by qualified personnel
familiar with the local standards in force.
2 GENERAL INFORMATION
2.1 ABOUT THIS USER MANUAL
This manual contains necessary information and procedures to install, configure, use and
troubleshoot the VarioString solar charge controllers. It does not contain information about
photovoltaic modules (PV) or batteries of various brands that can be connected. For this kind of
information, please refer to the instructions of each specific manufacturer.
It covers the following models and accessories:
MPPT solar charge controller:
Temperature sensor:
External auxiliary relay module:
BTS-01
VarioString VS-70,
ARM-02
VarioString VS-120
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This symbol is used to indicate safety instructions which, if not followed, could result in serious
personal injury or death to the operator or the user.
This symbol is used to indicate a general danger for the user and/or a risk of material
damage and/or the cancellation of the guarantee.
This symbol is used to indicate a procedure or function that is important for a safe and
correct use of the equipment. Failure to respect these instructions may lead to the
cancellation of the guarantee or to a non-compliant installation.
This symbol placed on the product indicates that its surfaces may reach temperatures
higher than 60°C.
This symbol placed on the product indicates that its use must follow the instructions in the
user’s manual.
The parameter table available at the end of this manual (chapter 16) must be kept updated
in case the parameters are modified by the operator or the installer.
If an authorised person modifies a parameter not included in the list (advanced
parameters), the number of the modified parameter(s), the specifications of the
parameter(s) and the new value set are to be indicated at the end of the table.
VarioString
2.2 IMPORTANT SAFETY INSTRUCTIONS
This manual contains important safety instructions. Read carefully the safety and operation
instructions before using the VarioString. Take into consideration all warnings mentioned both on the
equipment and in this manual, strictly following all instructions regarding its operation and use.
This user manual is intended to serve as a guideline for the safe and efficient use of the VarioString.
Anyone who installs or uses a VarioString can completely rely on this user manual and is bound to
observe all the safety instructions and indications here in.
The installation and commissioning of the VarioString must be entrusted to qualified personnel. The
installation and use must comply with the local safety instructions and standards in force in the
country.
2.3 CONVENTIONS
In general, values important for the operation of the equipment (for example: battery voltage during
absorption) are not mentioned and the parameter number is indicated in the following format:
{xxxxx}. The value of the parameter can be found in the table chap. 16.
In most cases, these values can be modified with the remote control RCC-02/03 (see chap. 10.1).
All values that are not followed by a parameter number may not be modified.
All digits and letters in brackets or in square brackets in the text of this manual refer to items
represented in illustrations with a circle.
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Never take off or damage the rating plate showing the serial number. It enables to check
and follow-up the data specific to each equipment and is vital for any warranty claim.
VarioString
2.4 QUALITY AND WARRANTY
During production and assembly of the VarioString, each unit undergoes several checks and tests
which strictly comply with established procedures. The manufacturing, assembling and testing of
each VarioString are completely carried out in our factory in Sion (CH). The equipment warranty
depends upon the strict application of the instructions in this manual.
The VarioString MPPT solar charge controller has a 5-year warranty (starting from the date of
production against material and manufacturing faults). A defective product will either be repaired
or replaced at the discretion of Studer Innotec.
2.4.1 Exclusion of warranty
No warranty claims will be accepted for damages resulting from handling, use or treatment that are
not explicitly mentioned in this manual. In particular, damages arising from the following causes are
excluded from the warranty:
Voltage higher than 600V across PV terminals (independent or parallel configuration) or
higher than 900V (series configuration).
Accidental presence of liquids in the equipment or oxidation due to condensation.
Damage resulting from falls, mechanical shocks or permanent or excessive vibrations.
Modifications carried out without the explicit authorisation of Studer Innotec.
Nuts or screws that have not been tightened sufficiently during the installation or
maintenance.
Damage due to atmospheric surge voltage (lightning).
Damage due to inappropriate transportation or packaging.
Disappearance of original identification marks.
2.4.2 Exclusion of liability
The installation, commissioning, use, maintenance and servicing of the VarioString cannot be subject
of monitoring by Studer Innotec. Therefore, we disclaim all responsibility and liability for damage,
costs or losses resulting from an installation that does not comply with the instructions, a faulty
operation or inadequate maintenance. The use of Studer Innotec equipment is in any case under
the responsibility of the customer.
This equipment is neither designed nor guaranteed to supply installations used for vital medical care
nor any other critical installation entailing potential risks of important damage to people or to the
environment.
We assume no responsibility for the infringement of patent rights or other third parties rights resulting
from the use of the MPPT solar charge controller VarioString.
Studer Innotec reserves the right to make any modifications to the product without prior notification.
Studer Innotec is not liable for incidental, direct or indirect damages of any kind, including any profit
loss, revenue loss or damages caused to equipment or goods due to defective equipment.
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HIGH-VOLTAGE DC INSIDE THE CHARGE REGULATOR: DANGER OF DEATH
When the VarioString is in operation it generates voltages that can be potentially lethal (up
to 600V (VS-70) and 900V (VS-120)). Any work on or close to the installation must only be
carried out by thoroughly trained and qualified personnel. Do not try to carry out ordinary
maintenance on this product yourself.
While working on the electrical installation, it is important to make sure that the source of
DC voltage coming from the battery as well as the source of DC voltage coming from the
photovoltaic generator, have been disconnected from the electrical installation.
Even when the VarioString has been disconnected from the power sources, a potentially
dangerous voltage may remain at the terminals. To eliminate this you have to wait for at least
5 minutes in order to allow the electronics to discharge. The task can then be carried out safely.
The VarioString can be installed at altitudes up to 3000m. For installations at higher
altitudes, please contact Studer Innotec SA.
The VarioString is in overvoltage category II, in accordance with the norm IEC/EN 621091:2010 that considers all solar generators as being in overvoltage category II.
The wiring and connection of the installation must be carried out only by perfectly qualified
personnel. The installation material such as cables, connectors, distribution boxes, fuses,
etc., must be appropriate and comply with the laws and regulations in force for the
application in question.
VarioString
2.5 WARNINGS AND GUIDELINES
The installation and commissioning of the VarioString must be entrusted to skilled and qualified
personnel perfectly aware of the safety precautions and local rules in force. All elements connected
to the VarioString must comply with the laws and regulations in force.
No person is authorized to proceed with any change, modification or repair of the equipment without
prior written authorisation from Studer Innotec. Only original parts should be used in authorised
modifications or replacements.
Respect the maximum rated specifications of the equipment indicated on the type label.
3 MOUNTING AND INSTALLATION
3.1 STORAGE
The equipment must be stored in a dry environment at an ambient temperature between -20°C and
60°C. Place the equipment at its mounting place at least 24 hours before commissioning in order to
avoid thermal shocks and condensation problems.
3.2 UNPACKING
When unpacking, check that the VarioString has not been damaged during transportation and that
all accessories listed below are present. Any fault must be immediately reported to the product
distributor or the contact mentioned at the back of this manual.
Carefully check the packaging as well as the VarioString.
Contents in the VarioString box:
VarioString
Installation and operation manual
Cable-glands for the battery cables
Solar cable connectors, 1 pair (VS-70) and 2 pairs (VS-120)
Communication cable
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The VarioString is a heavy equipment (5.5 kg (VS-70) and 7.5 kg (VS-120)) and must be mounted
to a support (wall) designed to bear such a load. It is imperative to ensure a complete and safe
fastening of the equipment. If simply hung, it may fall down and cause severe damages.
VarioString
3.3 MOUNTING PLACE
The mounting place for the VarioString is particularly important and must fulfil the following criteria:
Indoors
Protected from water and dust in a location without condensation.
Protected from any unauthorized person.
In a place where the relative humidity does not exceed 95%
In a place where the ambient temperature is between -20 and 55°C
In mobile applications, it is important to select a mounting place that ensures no vibration.
Protected from direct solar radiation or heat sources.
It should not be mounted directly above the battery or in a cabinet with the battery
The ventilation vents should be clear at all times and at least 20 cm from all obstacles that
could alter the ventilation of the device.
Given the norm IEC/EN 62109-1, the degree of pollution in the installation area should be at
maximum PD2 for the VS-120 and PD3 for the VS-70.
The support for the VarioString and the environment in which it is contained should not be
flammable.
The presence of a heat source may significantly reduce its rated power. Similarly, insufficient
ventilation may lead to the overheating of some internal components of the equipment. In this case,
the device will automatically limit its power as long as this abnormal situation persists.
As far as possible, reduce exposure to sudden temperature variation: important heat variation may
create undesired and harmful condensation inside the equipment.
3.4 FIXING/DIMENSIONS
The VarioString must be installed vertically. A distance of at least 5cm between the units and/or 20cm
around the equipment is required to guarantee adequate ventilation.
If the VarioString is installed in a closed cabinet, it must have sufficient ventilation to guarantee that
the ambient temperature is kept within the operating limits of the VarioString.
In motor vehicles, or when the support undergoes significant vibrations, the VarioString is to be
mounted on anti-vibration elements.
3.4.1 VarioString VS-120
Upper support screw: screw into the wall a 6-8 mm diameter screw without washer until there is 1.6
mm between the head of the screw and the wall. Hang the device from the screw. If deemed
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VarioString
necessary, the upper support screw can be fully tightened after hanging the device. In theory this is
only necessary in mobile applications. To access the upper support screw to fully tighten it, remove
the upper plastic grate.
Lower support screws: remove the lower plastic grate which gives access to the cabling
compartment. Carefully fix the device to the support with two screws (6-8 mm in diameter) using the
two mounting holes located at the bottom left and right of the cabling compartment.
3.4.2 VarioString VS-70
The VS-70 enclosure is fitted with a support plate to be mounted on
the back of the case using 4 screws M6, 8 mm long, and washers (see
fig. hereafter), before wall mounting. Mount it vertically with the
cable-glands downward.
The external cooling fan can be installed before or after the
equipment has been mounted on the wall.
The 4 mounting screws of the enclosure must be completely
tightened with a torque of (>3Nm - 10Nm<) in order to guarantee the
IP 54 protection index. Any unused cable glands should be closed in
a way that guarantees at least the same level of protection.
3.4.3 Assembling the cooling fan ECF-01
The VarioString VS-70 is supplied with an external cooling fan module (ECF-01). This module can be
installed before or after mounting the VarioString VS-70, on the wall.
This fan has a degree of protection IP54 and can be exposed to water spray without damage.
However, do not expose it to dirty water splashes in order to prevent mud or similar particles from
blocking the mechanism.
Assembly instructions:
1. Remove the plastic cap
and insert the connector
until the click sound.
2. Position the cover by
inserting the screws.
3. Fully tighten the two
screws.
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The connection of the VarioString charger is an important step of the installation.
It may only be carried out by qualified personnel, aware of the rules and regulations in force.
The installation must always comply with these standards. The cross-sections of the cables
connected to its terminals must comply with local regulations. All cables in use should be
isolated with PVC, TFE, PTFE, FEP, neoprene or polyimide.
Make sure that connections are completely tightened and that each wire is connected at
the right place.
The VarioString is intended to be connected exclusively to a source like a photovoltaic
generator, excluding any other energy source.
It is suitable for charging any type of lead-acid batteries. It is often possible to charge any
other type of battery using proper settings and with the express approval of the battery
supplier.
The connection compartment of the VarioString must remain permanently closed while the
apparatus is operating.
Before opening, check that all voltage sources (battery and PV) have been disconnected
or switched off and wait for at least 5 minutes before opening the equipment. It is imperative
to close the protection cover on the connection terminals after each servicing.
No.
Description
Comments
1
Terminal to connect the battery positive
pole
VS-70: M6, 5Nm torque, PG-16 (10-14mm)
VS-120: M10, 8Nm torque, PG-21
(13-18mm)
This connection must be done using a protection
and disconnection device if the pole has not
been earthed. For mounting of the internal fuse,
refer to sect. 4.2.2
2
Terminal to connect the battery
negative pole
VS-70: M6, 5Nm torque, PG-16 (10-14mm)
VS-120: M8, 8Nm torque, PG-21
(13-18mm)
This connection must be done using a protection
and disconnection device if the pole has not
been earthed.
3
Connector (Sunclix) for negative pole of
solar generator.
The solar generator wiring must be carried out in
compliance with the voltage and current limits
mentioned on the rating plate.
4
Connector (Sunclix) for positive pole of
solar generator.
5
Connector (Sunclix) for negative pole of
solar generator. (VS-120 only)
6
Connector (Sunclix) for positive pole of
solar generator. (VS-120 only)
7
Socket for connection of accessories BTS01 or ARM-02 (battery temperature
sensor and auxiliary relay module)
Only the mentioned original accessories can be
connected to this connector.
8
Socket for communication cables and
the remote control RCC-02/03.
RJ45 connector used for connecting equipment
of the Xtender family. These connections must be
carried out only with original Studer cables.
9
Termination switch
The switch must be placed in position O (towards
(8)) when both connectors are used.
10
Configuration switches (DIP switch)
The various possible configurations are described
in sect. 9.1
11
Real-time clock battery
(type CR 2032)
The equipment is fitted with a battery lasting
about 10 years.
VarioString
4 WIRING
4.1 ELEMENTS OF THE CABLE COMPARTMENT
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No.
Description
Comments
12
Remote entry
Available as from software version 1.5.22. Allows
the control of a function – to be defined by
programming – by the closing of a dry contact or
by the presence of a voltage across these
terminals.
13
Jumper for programming of the remote
entry
See sect. 8 – p. 27 in fig. 4.1.1 and 4.1.2. By default,
they are positioned at A-1/2 and B-2/3.
14
Battery protection fuse
VS-70 : Fuse 100A/80V (sect. 4.2.2.2)
VS-120 : Fuse CF8/150A/58V (sect. 4.2.2.1)
VarioString
4.1.1 VarioString VS-70
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VarioString
4.1.2 VarioString VS-120
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Using the VarioString connected to any other type of DC source without battery is strictly
forbidden and may cause significant damage to the equipment and / or to the source.
The use of other battery types like Ni-Cd, Li-ion or other is possible if the charge profile is
properly programmed, in accordance with the specifications of the battery manufacturer,
in agreement with the battery manufacturer and under the responsibility of the installer.
VarioString
4.2 CONNECTING THE BATTERY
The VarioString is a device which DC (battery) connection is to be connected exclusively to a battery.
Most of the time, lead-acid batteries with liquid (VLA, VRLA) or gelled (GEL) and AGM electrolyte
may be used. It can be easily configured to create charge profiles that are compatible with these
various types of lead-acid batteries.
In any case, the max charge current should be within the limit established by battery manufacturer.
If necessary, the charge current can be limited with the aid of parameter {14001}.
4.2.1 Precautions when using the batteries
The batteries should only be chosen, dimensioned and installed by qualified personnel, trained in this
specific area. When working with batteries, a second person is required in order to give assistance in
case of problems.
Lead-acid batteries with liquid or gelled electrolyte produce a highly explosive gas during normal
use. Avoid any source of sparks or fire in the immediate vicinity of the batteries. The batteries must be
kept in a well-ventilated place and installed so as to avoid accidental short-circuits when
connecting.
Never try to charge frozen batteries.
It is advised to never work alone with batteries. The presence of a second person is necessary to
provide assistance in the event of a problem.
Sufficient fresh water and soap must be kept close at hand to allow adequate and immediate
washing of the skin or eyes affected by accidental contact with the battery acid.
In the event of accidental contact of the eyes with acid, they must be washed carefully with cold
water for 15 minutes. Then immediately consult a doctor.
The battery acid can be neutralized with baking soda, among other things. A sufficient quantity of
baking soda should be available for this purpose.
Particular care is required when working close to batteries with metal tools. Tools such as screwdrivers,
open-ended spanners, etc., may cause short circuits. Sparks created by short-circuits may cause the
battery to explode. Therefore these kinds of tools must always have isolated handles and never be
placed on top of a battery.
When working with batteries, all metal jewellery such as rings, watches with a metal bracelet,
earrings, etc., must be taken off. The current supplied by the batteries during a short circuit is
sufficiently powerful to melt the metal and cause severe burns.
Batteries at the end of their life-cycle should be recycled in accordance with directives from the
responsible local authorities or the battery supplier. The batteries should never be thrown into fire as
they may explode. Under no circumstances should you try to take apart or dismount the battery, as
they contain toxic and polluting materials.
For ungrounded battery systems, always check that they are not inadvertently grounded before
starting working on the batteries.
Always follow carefully the instructions of the battery manufacturer.
If the battery voltage exceeds 68V, the charger turns off and starts again when the voltage is lower
than 64V.
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A battery voltage higher than 75V can cause important damage or destroy the equipment.
Such a voltage applied on equipment connected downstream like Xtender
inverters/chargers or other, can cause important damage or destroy the equipment!
Each VarioString is connected directly to the battery using its own protective device. All other
consumers or sources are connected directly to the battery through their own protective device.
In multi-unit systems (connected to the same communication bus), all VarioStrings must be
connected to the same battery bank.
An annual check of all the connection tightness is recommended. In mobile installations,
the connection tightness should be checked more often.
Battery cables must always be protected by a protection and disconnection device (fuse,
circuit breaker) on the pole not connected to earth.
The protection device must be rated according to the cable cross-section but must not exceed
1.25 x VarioString maximum current. It will be mounted as close as possible to the battery.
a = M10 cable lug!!
b = bolt M8x30
c = washer
d = ceramic washer
e = fuse CF8 (58V, 150A)
VarioString
4.2.2 Connecting the battery
All connection cables as well as the battery cables must be mounted using cable restraints in order
to avoid any pulling on the connection.
Battery cables must be as short as possible and the cross-section must comply with the regulations
and standards in force. Tighten the clamps on the “Battery” inputs sufficiently.
Lead batteries are usually available in 2V, 6V or 12V blocks. In most cases, in order to get the correct
operating voltage for the VarioString, several batteries must be connected in series. The capacity of
the batteries can be increased using a parallel connection of several battery strings.
Some battery manufacturers limit the use or advice against parallel connection of battery strings.
Strictly conform to the manufacturer's instructions of use.
4.2.2.1 VarioString VS-120
4.2.2.2 VarioString VS-70
See illustration on page 12, number (1) and (2). M6 cable lug.
4.2.3 Protection device of the battery
The battery cables must be as short as possible. The recommended cable cross-section is 25mm2 for
VS-70 and 50mm2 for VS-120. The protection devices (battery side) must be 80A for VS-70 and 125A
for VS-120. The protection device must be installed as close as possible to the battery. The
recommended cross-section of battery cable is valid for lengths up to 3m. Beyond this length, it is
recommended to oversize the section of the battery cables.
Any other sources or loads existing on the battery must be connected using their own protection
devices. Never connect them to the protection device(s) of the VarioString.
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VS-120
600 V max for independent and parallel cabling
900 V max for series cabling
VS-70
600V
The whole solar system must be installed according to protection class II.
The capacitor banks inside the VS-120 hold a DC voltage for several minutes after the PV
input is disconnected. It is necessary to wait 10 minutes before reconnecting the PV input
cables after making any changes to the PV array or its wiring.
When connecting the PV inputs in parallel, it is necessary to first connect the VarioString
MPPT channel inputs in parallel, and then connect the PV array positive and negative
cables to the paralleled VarioString positive and negative inputs.
VarioString
4.3 PHOTOVOLTAIC GENERATOR (PV)
The VarioString may accept the following maximum input voltages:
4.3.1 Dimensioning
The solar generator is dimensioned to cover an important part or the entire power requirement of the
system. Once the power has been decided upon, it will be distributed among one or more solar
charge regulators, wisely combining the modules among them. These combinations in series and in
parallel must be carried out according to the voltage and current limits of the VarioString solar
charge controller.
The possible operating range of the VS-70 is illustrated in the graph below:
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VarioString
The VS-120 possible operating range within different configurations are indicated in the graph below
(blue (A): one independent input, red (B): two inputs in parallel, green (C): two inputs in series).
4.3.2 Serial connection (chain or string) of PV modules
To get the optimum voltage, connect the PV modules in series to form a string with the desired
voltage.
When using the two entries of the VarioString VS-120 in series, the + terminal of the PV1 entry (6) should
be connected to the + pole of the PV generator. The – terminal of the PV2 entry (3) should be
connected to the – pole of the PV generator and a bridge should be made between the entries (4)
and (5).
The open-circuit voltage of the string must be lower than 600V under any temperature and irradiation
conditions. A 10 to 20% margin is recommended in order to cover these unknowns. When the two
inputs are used in series on the VarioString VS-120, the maximum open-circuit voltage should not
surpass 900V.
To establish the maximum numbers of the PV modules connected in series in the same string, use the
following formula: 600V/(Uoc*1.1). (Example: 600/(22*1.1)=24.79). The result must be rounded down
(i.e. 24 modules - of 22 Voc - in series for the above example).
The table below gives an idea of the possible arrangements for common PV modules according to
the number of cells or their type:
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36 cell
module
Voc < 25V
60 cell
module
Voc < 42V
72 cell
module
Voc < 50V
Thin film
module
Voc < 110V
max.
max.
max.
--
21
12
10
4
For VS-70 or VS-120 with
independent or parallel inputs
32
19
16
7
For VS-120 with two inputs in series
The two inputs can only be put in parallel when there is no voltage present. The four inputs
(3), (4), (5) and (6) should be disconnected at least 10 minutes before connecting the "Y"
cable in parallel.
1. Disconnect all PV sources and wait 10 minutes.
2. First connect the inputs (3) and (5), and (4) and (6) with the "Y" parallel cable.
3. Only at this point, the PV generators may be connected to the "Y" cables.
Maximum recommended power
for the solar generator
VS-120
Battery
MPPT input 1
3500W
48V
MPPT input 2
3500W
48V
Total
7000W
48V
The VarioString has a current limit. At any given time, the maximum power of the VarioString
depends on the charging phase voltage of the battery. For example, if the charging phase
is Bulk, and the battery voltage is 50V, the maximum power output for the VS-120 is 120A *
50V = 6000W and for the VS-70 70A*50V = 3500W. Even if more solar energy is available, the
battery charge current will not exceed 120A (VS-120) and 70A (VS-70).
VarioString
Beware of the PV module temperature! The above values are for modules under standard test
condition (STC).
4.3.3 Parallel connection of PV module strings
To get the required charging power, 2 or more strings can be connected in parallel. Each string
connected in parallel shall be composed of the same number of modules of the same type.
When using the two entries on the VarioString VS-120 in parallel (up to 26A) it is necessary to physically
connect the two negative terminals (3) and (5) as well as the two positive terminals (4) and (6).
The number of strings connected in parallel depends on the power of each module. The sum of the
power of all the panels connected to a VarioString should not exceed the power that the VarioString
can charge.
The recommended number of strings to be connected in parallel is equal to 3500W divided by the
power of a string and rounded down to the nearest whole number. (see table below)
For example, with 12 modules of 110W in series: 3500/1320=2.65 => 2 strings (2640W) can be
connected in parallel.
If both VarioString inputs are connected in parallel, for the
strings of 12 modules in series mentioned above, 5 strings
could be connected in parallel (7000/1320=5.3 =>5).
The PV generator can be over-dimensioned in order to get
the required charging power even when solar irradiation is
lower. In this case, a part of the solar energy will be lost
when the solar irradiation is higher because the VarioString
will reach its current limit and curtail power output. By looking at the example above, 3 strings could
be used however the maximum power of 3960W will not be reached as the VarioString will limit the
power to a maximum value of 3500W.
4.3.3.1 Maximum current of the solar generator
The maximum current of the solar generator is limited to 13 A for the VS-70 and the VS-120 when
connected in series or independently (13A per input) or to 26A for the VS-120 when connected in
parallel.
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The VarioString is meant for PV generators supplying up to 600V (900V in series). This voltage
is dangerous for human beings.
During the installation or the maintenance of the system, it is imperative to make sure that
no dangerous voltage may surge in the system. The disconnection device must be open
and secured against any accidental reclosing.
Under no circumstances should PV module inputs of several VarioString be put in parallel.
In multi-unit systems (connected to the same communication bus), all VarioStrings must be
connected to the same battery bank.
When the VarioString units are not synchronized, they must be programmed in the same
way and it is recommended to not activate the periodical equalization function. The
equalization can be started manually or will be done by the synchronized units.
When the devices are in the voltage regulation phase, their respective currents may
considerably differ. These differences have no effect at all on the charge quality.
VarioString
In any case, the VarioString will limit the charging current (battery) to its rated current of 120A for the
VS-120 or 70A for the VS-70.
4.3.4 Safe use of the photovoltaic modules
4.3.5 Protection devices
Wiring protection devices (fuses, circuit breakers) connecting the PV generator to the VarioString
must be installed in accordance with local standards and regulations in force.
The DIN VDE 0100-712 standard prescribes a switching device on all poles between the PV generator
and the charge regulator. This device must be supplied by the installer.
PV modules are often exposed to stormy weather. It is highly recommended to install lightning
protection (see chap. 4.5).
4.3.6 Cable cross-section and connection
The connection cable cross-section must be chosen according to the short-circuit current of the PV
generator and the local installation rules. PV connectors of Sunclix type do not need any special tools
for mounting. They accept cables between 2.5 and 6mm2 (exterior of 5 to 8mm2). Strip the cable
15mm to attach the Sunclix connector.
4.3.7 Parallel connection of several VarioString
As many VarioStrings as necessary can be connected in parallel on the same battery bank
according to the battery capacity. Each will have its own independent solar generator (connected
in independent, parallel or series configuration) and include its own disconnection and protection
device to the battery.
Up to 15 VarioStrings can be synchronized and interconnected to the same communication bus (see
chap. 4.6) on a single system. Beyond these 15 units, any additional unit will not be interconnected
and thus their battery cycles will work independently.
Solar generators may be of various types and be orientated differently. Each VarioString will adjust
the optimum point of the PV generator independently of the other units connected to the same battery.
For multi-unit systems, the devices are connected to each other by a communication bus (see chap.
4.6) via the connectors (8) and a cable (ref. CAB-RJ45-8-2) with a maximum length of 5 meters.
As long as they are correctly connected together by the communication cable, the VarioString
automatically synchronize the battery charge cycle.
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If a VarioString is connected to another compatible device (Xtender, VarioTrack, VarioString,
BSP, RCC, Xcom) with the same communication bus, it is highly recommended to make a
software update of all components in the system in order to guarantee all functionalities.
During the commissioning of the equipment in a multi-unit configuration, the system checks
automatically the compatibility of the software versions and may prevent the operation in
case of incompatibility. An upgrade of the installation must then be carried out by means
of the RCC-02/03 remote control using the latest manufacturer's software version (read the
user manual for the control and monitoring unit RCC-02/03 to carry out this operation).
The whole solar system must be installed according to protection class II.
VarioString
4.3.8 Extension of an existing installation
In interconnected installations, if the software is compatible, it is possible to extend an existing
installation by adding one or several (up to 15) VarioString units in parallel.
4.4 EARTHING
The VarioString is a Class I protection equipment,
its metal case must be earthed by means of the
grounding screw, included for that purpose.
= protective earth (connected to the
enclosure of the equipment).
The solar generator (as well as its wiring) must be
Class II isolated.
The cross-section of the earthed cable must not be
less than 16mm2.
In any case, the protective earth must be connected in accordance with local standards and regulations
in force. The protective earth of the equipment must at least be connected to the earthed ground of all
the Class I equipment after and before the VarioString (equipotential connection). The information, notes,
recommendations and diagrams reported in this manual are subject to local installation rules. The installer
is responsible for the conformity of the installation with the local standards in force.
4.4.1 Detecting an earthing fault
The choice of earthing system for the DC circuit is an important factor for the individuals' safety. Once
the decision is made the VarioString can check the continuity of the earth connection.
In case of failure of this connection, the LED (3) (see sect. 6) lights up indicating the fault. A permanent
message (requiring a validation) is displayed on the RCC if present.
The parameters {14040}, {14041} and {14042} allow establishing the type of control to be carried out
or the absence of control as set by default.
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