Page 1
v110901
Sun. Water. Life.
BERNT LORENTZ GmbH & Co. KG Kroegerskoppel 7, 24558 Henstedt-Ulzburg, Germany, Tel. +49 (0) 4193 7548 - 0, Fax - 29, www.lorentz.de
Errors excepted and possible alterations without prior notice.
Photovoltaic (PV) Modules - LA Series
Installation Manual
WARNINGS
HAZARDOUS ELECTRICITY! CAN
SHOCK, BURN, OR CAUSE DEATH! AUTHORISED, QUALIFIED PERSONNEL
ONLY! DO NOT TOUCH TERMINALS!
GROUND POSITIVE SIDE OF ARRAYS!
PV modules generate electricity when exposed to light. Modules may be covered with an opaque material during installation to avoid shocks or burns. Do not touch live terminals
with bare hands, wear security gloves. Use insulated tools
for electrical connections.
PERMIT AND INSPECTION
Contact local authorities and determine the necessary permit, installation and inspection requirements in your area.
PV MODULES
LORENTZ PV modules consist of a series of electrically interconnected crystalline silicon solar cells, which are permanently laminated within a pottant and encapsulated between a tempered glass cover plate and a back sheet. The
entire laminate is secured within an anodised aluminium
frame for structural strength, easy installation, and to protect
the cells from the most severe environmental conditions.
APPLICATIONS
LORENTZ PV modules are ideal to power a wide range of
electrical appliances in remote places far away from the
electricity grid, either with or without the use of storage batteries, even under toughest climate conditions.
WARNING Not to be used for applications that connect to the utility grid.
Warranty and liability void if done otherwise.
Typical applications are
water pumping,
water purification systems,
remote village lighting,
solar home systems (SHS),
street and camp lights,
traffic signals,
hospitals and medical facilities,
microwave/radio repeater stations,
battery charging,
telecommunication systems,
etc.
ing structure. The four holes close to the corners of the module are most often used for attachment. Refer to drawing in
the product information sheet for the position of these holes.
The stainless steel hardware (e.g. AISI 304) used for securing
the module frame should secured with an applied torque of
about 8 Nm (6 foot-pounds).
In order to protect the electric connections from dampness and rain, the PV
module must be set up in such a way
that the notches of the junction box are
orientated downwards.
Clearance between the module frame
and the mounting surface may be required to prevent the junction box from
touching the surface, and to allow the
circulation of cooling air around the back of the
module. If the modules are to be installed on the
roof or wall of a building, the standoff method or
the rack method is recommended.
The module frame is made of anodised
aluminium; therefore corrosion can oc-
cur if the module gets in contact with
another type of metal in a salt water
environment (electrolysis corrosion). To avoid this,
PVC or stainless steel washers can be placed between the solar module frame and support structure.
WIRING
All of the LORENTZ PV modules utilise a junction box. This
junction box, located on the back side of the module, is
weatherproof and is designed for standard wiring or conduit
connections. For modules of 75 Wp and more cables are included.
Proper connection of the cables in the
junction box must be checked especially for modules with pre-assembled ca-
bles as vibrations during transport
might loosen the wiring. Connectors must be used
with same type only to guarantee safe connection.
LORENTZ advises that all wiring and electrical connections
comply with National Electrical Codes. A cable clamp with
a minimum rating of IP65 must be used to maintain the
weatherproof integrity of the junction box. Bypass diodes are
preinstalled at factory.
To wire LORENTZ PV modules:
Determine the nominal system array voltage of your
system. Each panel is equivalent to a 12 VDC nominal
block for 12S modules and 24 VDC nominal block for
24S modules. Standard array voltages 12, 24, 48 and
96 V are shown as examples in Figure 3.
SITE SELECTION, TILT ANGLE
In most applications, the location of LORENTZ PV modules
should be chosen to provide maximum irradiation throughout the year. In the Northern hemisphere, the modules
should face south, and in the Southern hemisphere, the
modules should face north. Modules facing 30° away from
true South (or North) will lose approximately 10-15 % of
their power output. If the module faces 60° away from true
South (or North), the power loss will be 20-30 %.
The module tilt angle is measured between the solar modules and the ground (Figure 1). For installations where the
solar modules are attached to a permanent structure, the
solar modules should be tilted for optimum winter performance. If the system power production is adequate in the winter, it will be satisfactory during the rest of the year. Refer to
Table 1 for the recommended module tilt angle at your site.
Avoid trees, buildings or obstructions which could cast
shadows on the solar modules especially during the winter
months when the arc of the sun is lowest over the horizon.
Table 1: Recommended tilt angles for fixed systems
based on Winter Performance
site latitude fixed tilt angle
0° to 15° 15°
15° to 25° same as latitude
25° to 30° latitude + 5°
30° to 35° latitude +10°
35° to 40° latitude +15°
above 40° latitude +20°
INSTALLATION
Installation by qualified personnel only. Personnel must
know the appropriate safety procedures.
Sunlight shall not be concentrated on the module.
LORENTZ PV modules are quite rugged; nonetheless
the glass can be broken (and the module will no longer
work properly) if it is dropped or hit by tools or other
objects, or when the modules are stepped upon.
Module support structures that are to be used to sup-
port LORENTZ PV modules should be wind rated according to local conditions and approved for use by the
appropriate local and civil codes prior to installation.
Fixation
The frame of each module has four 6.6 mm diameter
(0.26 in) mounting holes to fix the modules to the support-
Page 2
v110901
Sun. Water. Life.
BERNT LORENTZ GmbH & Co. KG Kroegerskoppel 7, 24558 Henstedt-Ulzburg, Germany, Tel. +49 (0) 4193 7548 - 0, Fax - 29, www.lorentz.de
Errors excepted and possible alterations without prior notice.
The wire used to interconnect the solar modules may
be single or two conductors, from 2 mm² (AWG 14) up
to 6 mm (AWG 10) gauge stranded copper wire, in a
sunlight-resistant jacket UF cable that will not degrade
when exposed to the direct sunlight. The maximum
and minimum outer diameters of the cable that may
be used with the cable connector are 8 mm and 6 mm
respectively.
Route wires through the PG plugs and clamps refer to
installation example.
Gently hand-tighten the terminal screws with cross tip
(Phillips head) screwdriver. Do not over tighten to avoid
damages to the terminal.
The output wiring from the final module is generally run
to a separate array junction box. In commercial system,
this wiring from the array box to the next component
(i.e. fuse box or charge regulator etc.) is generally run in
conduit. The maximum electrical rating of an acceptable
series fuse is 6 to 12 A.
After checking that module wiring is correct, close all
the junction boxes and ensure a waterproof seal.
GROUNDING
LORENTZ PV modules must only be used in configurations
with galvanic insulated inverters , that are not connected to
the grid (stand alone inverters), with the positive (+) polarity
of the PV array connected to ground protected by a fuse.
Failure to comply with this requirement will reduce the performance of the system and void the Limited Power Warranty.
Attach all module frames to an earth ground. Attach a separate ground wire to one of the holes marked “ground” on
the module frame with a screw and bonding or external
tooth washer. This is to ensure positive electrical contact
with the frame. The racks must also be grounded unless they
are mechanically connected by nuts and bolts to the grounded modules. The array frame shall be grounded in accordance with NEC Art. 250.
Positive Grounding
LORENTZ PV modules – LA series – use all-back contact
solar cells for high efficiency. This technology leads to possibly suffering from a temporary decrease in performance if
installed according to common methods without grounding
or with negative grounding. This effect is due to a surface
polarization effect caused by a small amount of leakage current from the module. While all modules experience some
amount of leakage current, the surface polarization effect
seems to be unique to thin-film and back-contact solar cells.
If the frame of the module is on a low potential compared
to the cells voltage, the leakage current flows from the cells
through the glass to the frame. This causes a negative effect
in the cells which decreases the performance of the module.
This surface polarization effect is normally reversible by positive grounding. It usually does not cause any damage to the
module. The performance of a system that has been installed
according to common methods (without grounding or with
negative grounding) and is suffering from decreased performance can normally be restored by wiring it as a positivegrounded system.
If an off-grid AC stand alone inverter is used and the system
is positive-grounded, an isolated type must be applied. Most
standards forbid using a non-isolated (trafoless) stand alone
inverter in a system grounded on the DC side, as it can be
dangerous. There must be a real electrical separation between DC and AC.
To avoid a negative charge on the frame and thus on the
surface of the modules, the system has to be grounded on
the most positive voltage in the system, which is the positive
pole of a single module or the whole string. In every case,
ground has to be connected to the frame of the modules.
If real grounding is not possible, at least the frame has to
be connected to the most positive in the system. Basically,
ground has to be connected only at one single point to the
most positive voltage of the system. See figure 4.
Make sure to follow the local standards and codes.
For PV generators, for which positive
grounding is not possible and which
have an open circuit voltage of up to
48 V DC (up to 2 pieces LAXX-12S connected in series or one LAXX-24S), a positive
grounding is not required. The PV modules can be
grounded to minus.
BLOCKING DIODES
Blocking diodes are typically placed between the battery and
the PV module output to prevent battery discharge at night.
LORENTZ PV modules are made of monocrystalline cells with
high electrical “back flow” resistance to night-time battery
discharging. As a result, LORENTZ PV modules do not contain a blocking diode when shipped from the factory. Most
PV charge regulators do have night-time disconnect feature,
however.
BYPASS DIODES
Partial shading of an individual module in a 12 V or higher
source circuit string (i.e. two or more modules connected in
series) can cause a reverse voltage across the shaded module. Current is then forced through the shaded area by the
other modules. When a bypass diode is wired in parallel with
the series string, the forced current will flow through the
diode and bypass the shaded module, thereby minimizing
module heating and array current losses.
Diodes that are used as bypass diodes must:
have a Rated Average Forward Current [IF(AV)] above
maximum system current at highest module operating
temperature.
have a Rated Repetitive Peak Reverse Voltage [VRRM]
above maximum system voltage at lowest module operating temperature.
BATTERY
When using the solar modules for charging batteries, the
battery must be installed in such way as ensures the performance of the system and the safety of its users. Follow
the battery manufacturer’s guidelines for installation, operation and maintenance recommendations. The battery (or
battery bank) should be kept from passing-by people and
animal traffic, protected from sunlight, rain, snow, debris,
and its location be well ventilated. Most batteries generate hydrogen gas when charging, which can be explosive;
in this case provide sufficient ventilation and do not light
matches or create sparks near the battery bank. For outdoor
installation, the battery should be placed in an insulated and
ventilated battery case thatis specifically designed for the
purpose.
MAINTENANCE
Inspect all PV modules annually for safe electrical connections, sound mechanical connection and freedom from corrosion.
Normally the rainfall is sufficient to keep the module glass
surface clean. If dirt build-up becomes excessive, clean the
glass surface only with a soft cloth using mild detergent
and water. Remove fingerprints with standard glass cleaner.
Do not use harsh cleaning materials, such as scrapers, steel
wool, blades or other sharp instruments to clean the surface;
this will void the warranty.
Use caution when cleaning the back surface of the module to avoid penetrating
the PVF sheet.
Modules that are mounted flat (0° tilt angle) should be
cleaned more often, as they will not ”self-clean“ as effectively as modules mounted at a 15° tilt or greater.
Once a year, check the tightness of terminal screws and the
general condition of the wiring. Make sure that mounting
hardware is tight. Loose connections will result in a damaged module or array.
NOTES
The electrical characteristics are indicated values of
Pmax under standard test conditions (irradiance of
1,000 W/m2, AM 1.5 spectrum, and cell temperature
of 25° C).
Under certain conditions, a photovoltaic module is likely
to produce more current and/or voltage than reported
at standard test conditions. Accordingly, the values of
Isc and Voc marked on this module should be multiplied
by a factor of 1.25 when determining component voltage ratings, conductor ampacities, fuse sizes, and sizes
of regulators which are connected to the PV output.
Page 3
v110901
Sun. Water. Life.
BERNT LORENTZ GmbH & Co. KG Kroegerskoppel 7, 24558 Henstedt-Ulzburg, Germany, Tel. +49 (0) 4193 7548 - 0, Fax - 29, www.lorentz.de
Errors excepted and possible alterations without prior notice.
Figure 4
Positive Grounding
charger, inverter or
pump controller
charger, inverter or
pump controller
Figure 4a:
Connecting a single module
Figure 4b:
Connecting two or more modules in series
connection
to frame
connection
between frames
optional:
more modules
in series
DC circuit
breaker
DC circuit
breaker
connection
to frame
Figure 1
Tilt Angle
sunlight
module
tilt angle
Figure 2
Fixation with screws
M6 screw
washer
washer
spring washer
nut
Figure 3
Standard Wiring Examples
Figure 3a
12 V (Vmp ~ 17 V) parallel for 12S modules
24 V (Vmp ~ 34 V) parallel for 24S modules
Figure 3b
24 V (Vmp ~ 34 V) series for 12S modules
48 V (Vmp ~ 68 V) series for 24S modules
Figure 3c
48 V (Vmp ~ 68 V) series for 12S modules
96 V (Vmp ~ 136 V) series for 24S modules
red
red
red
black
junction box
black
black
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