3. Installation
3.1. Location of the MPPT
 | For best operating results, the MPPT should be placed on a flat vertical surface. To ensure a trouble free operation, it must be used in locations that meet the following requirements: a) Do not expose to water, rain or moisture. b) Do not place in direct sunlight. Ambient air temperature should be between -20°C and 40°C (humidity & 95% non-condensing). c) Do not obstruct airflow. Leave at least 30 centimeters clearance above and below the MPPT. When the unit is running too hot, it will shut down. When it has reached a safe temperature level the unit will automatically restart again. Figure 1. Thermal image of MPPT RS heat zones required for clearance.  |
 | This product contains potentially dangerous voltages. It should only be installed under the supervision of a suitable qualified installer with the appropriate training, and subject to local requirements. Please contact Victron Energy for further information or necessary training. |
| Excessively high ambient temperature will result in the following: · Reduced service life. · Reduced charging current. · Reduced peak capacity, or shutdown of the MPPT. Never position the appliance directly above lead-acid batteries. The MPPT RS is suitable for wall mounting. For mounting purposes, a hook and two holes are provided at the back of the casing. The device must be fitted vertically for optimal cooling. |
| For safety purposes, this product should be installed in a heat-resistant environment. You should prevent the presence of e.g. chemicals, synthetic components, curtains or other textiles, etc., in the immediate vicinity. |
ImportantTry and keep the distance between the product and the battery to a minimum in order to minimise cable voltage losses | |
3.2. MPPT grounding, detection of PV array insulation faults & Earth fault alarm notification
The RS will test for sufficient resistive isolation between PV+ and GND, and PV- and GND.
In the event of a resistance below the threshold (indicating an earth fault), the inverter shuts down and disables the ac outputs (mppt keeps charging the battery as this has no impact on safety due the isolation to the battery side).
If an audible alarm and/or email notification of this fault is required, then you must also connect a GX device (such as the Cerbo GX). Email notifications require an internet connection to the GX device and a VRM account to be configured.
The positive and negative conductors of the PV array must be isolated from ground.
Ground the frame of the PV array to local requirements. The ground lug on the chassis should be connected to the common earth.
The conductor from the ground lug on the chassis of the unit to earth should have at least the cross-section of the conductors used for the PV array.
When a PV resistance isolation fault is indicated, do not touch any metal parts and immediately contact a suitably qualified technician to inspect the system for faults.
The battery terminals are galvanically isolated from the PV array. This ensures that PV array voltages cannot leak to the battery side of the system in a fault condition.
3.3. Battery and battery lead requirements
In order to utilize the full capacity of the product, batteries with sufficient capacity and battery cables with sufficient cross section should be used. The use of undersized batteries or battery cables will lead to:
Reduction in system efficiency.
Unwanted system alarms or shutdowns.
Permanent damage to system.
See table for MINIMUM battery and cable requirements.
Model | 450/100 | 450/200 | |
|---|---|---|---|
Battery capacity Lead-acid | 200 Ah | 400 Ah | |
Battery capacity Lithium | 50 Ah | 100 Ah | |
Recommended DC fuse | 125 A - 150 A | 250 A | |
Minimum cross section (mm2) per + and - connection terminal | 0 - 2 m | 35 mm2 | 70 mm2 |
2 - 5 m | 70 mm 2 | 2 x 70 mm 2 |
Warning
Consult battery manufacture recommendations to ensure the batteries can take the total charge current of the system. Decision on battery sizing should be made in consultation with your system designer.
| Use a torque wrench with insulated box spanner in order to avoid shorting the battery. Maximum torque: 14 Nm Avoid shorting the battery cables. |
Undo the two screws at the bottom of the enclosure and remove the service panel.
Connect the battery cables.
Tighten the nuts well for minimal contact resistance.
3.4. Solar input wiring
The MPPT RS 450/100 and the MPPT RS 450/200 Solar charge controllers are available with two different options for PV cable connection methods.
The "- Tr" version has screw terminal blocks inside. The PV cables pass through glands on the bottom of the unit and the lower cover must be removed to access the terminal blocks inside.
The "- MC4" version has MC4 connectors presented on the bottom of the unit. The bottom cover does not need to be removed to connect the PV cables.
Notice
For the "- Tr" version, the terminal block screws should be tightened to a torque of 1.2Nm.
The MPPT 450/100 - MC4 version has two male and female pairs of MC4 connectors - one pair per tracker.
Side-by-side comparison of the MPPT RS 450/100 - MC4 (left) and MPPT RS 450/100 - Tr (right).
The MC4 connectors are pre-wired, whereas the "- Tr" version has screw terminal blocks, PV wires pass through cable glands at the bottom of the unit.
The MPPT 450/200 - MC4 version has four male and female pairs of MC4 connectors - one pair per tracker.
Side-by-side comparison of the MPPT RS 450/200 - MC4 (left) and MPPT RS 450/200 - Tr (right).
The MC4 connectors are pre-wired whereas the "- Tr" version has screw terminal blocks, PV wires pass through cable glands at the bottom of the unit.
3.5. Solar array configuration
The MPPT RS must keep the individual tracker inputs isolated from each other. That means one solar PV array per input, do not attempt to connect the same array to multiple tracker inputs.
Warning
The maximum rated voltage of the solar charger is 450 V. A PV overvoltage event will damage the solar charger. This damage is not covered by warranty.
In case the PV array is located in colder climates the PV array can output more than its rated Voc. Use the MPPT sizing calculator on the solar charger product page to calculate this variable. As a rule of thumb, keep an additional 10% safety margin.
The maximum operational input current for each tracker is 18 A.
MPPT PV inputs are protected against reverse polarity, to a maximum short circuit current of 20 A for each tracker.
Connecting PV arrays with a higher short circuit current is possible, up to an absolute maximum of 30A, as long as connected with correct polarity. This outside of specification potential allows for system designers to connect larger arrays, and can be useful to understand in case a certain panel configuration results in a short circuit current just slightly above the maximum of the reverse polarity protection circuit.
Solar PV input cable insulation should be removed to allow 12 mm of exposed copper into the PV attachment point on the MPPT. It should not be possible to come into contact with any exposed copper wiring, the fit must be clean without any stray strands.
Warning
BEWARE that the product warranty will be void if a PV array with a short circuit current larger than 20 A array is connected in reverse polarity.
Caution
The MPPT RS must keep the individual tracker inputs isolated from each other. That means one solar PV array per input, do not attempt to connect the same array to multiple tracker inputs.
When the MPPT switches to float stage it reduces battery charge current by increasing the PV Power Point voltage.
The maximum open circuit voltage of the PV array must be less than 8 times the minimum battery voltage when at float.
For example, where a battery has a float voltage of 54.0 volts, the maximum open circuit voltage of the connected array cannot exceed 432 volts.
Where the array voltage exceeds this parameter the system will give a "Over-charge Protection" error and shut down.
To correct this, either increase the battery float voltage, or reduce PV voltage by removing PV panels from the string to bring the voltage back within specification.
3.5.1. MPPT RS example PV configuration
Notice
This is an example of an array configuration. The decision on the specific array configuration, sizing and design for your system should be made in consultation with your system designer.
Panel Type | Voc | Vmpp | Isc | Impp | # of panels | Max String Voltages | Power total per string |
|---|---|---|---|---|---|---|---|
Victron 260W (60 cell) | 36.75 V | 30 V | 9.30 A | 8.66 A | # 1 - 11 #2 - 8 | # 1 - 404 V # 2 - 304V | 2850 W 2080 W |
 |
3.6. Cable connection sequence
First: Confirm correct battery polarity, connect the battery.
Second: if required, connect the remote on-off, and programmable relay, and communications cables
Third: Confirm correct PV polarity, and then connect the solar array (if incorrectly connected with reverse polarity, the PV voltage will drop, the controller will heat up but will not charge the the battery).
3.7. Synchronised parallel operation
Several charge controllers can be synchronised with the CAN interface. This is achieved by simply interconnecting the chargers with RJ45 UTP cables (bus terminators needed, see section 3.6).
The paralleled charge controllers must have identical settings (e.g. charge algorithm). The CAN communication ensures that the controllers will switch simultaneously from one charge state to another (from bulk charge to absorption for example). Each unit will regulate its own output current, depending on the output of each PV array and cable resistance.
In case of synchronized parallel operation, the network icon will blink every 3 seconds on all paralleled units.
The PV inputs should not be connected in parallel. Each charge controller must be connected to its own PV array.
3.8. Energy Storage System (ESS)
An Energy Storage System (ESS) is a specific type of power system that integrates a power grid connection with a Victron Inverter/Charger, GX device and battery system. It stores solar energy into your battery during the day for use later on when the sun stops shining.
Please refer to the following manual how to setup an ESS:
3.9. User I/O
3.9.1. Remote on/off connector
The remote on/off connector has two terminals, the “Remote L” and the “Remote H” terminal.
The SmartSolar MPPT RS ships with the remote on/off connector terminals connected to each other via a wire link.
Note that for the remote connector to be operational, the main on/off switch on the solar charger needs to be switched to “on”
The remote on/off connector has two different operational modes:
On/off mode (default):
The default function of the remote on/off connector is to remotely switch the unit on or off.
The unit will switch on if “Remote L” and the “Remote H” are connected to each other (via a remote switch, relay or the wire link).
The unit will switch off if “Remote L” and the “Remote H” are not connected to each other and are free floating.
The unit will switch on if “Remote H” is connected to battery positive (Vcc).
The unit will switch on if “Remote L” is connected to battery negative (GND).
2-wire BMS mode:
This feature can be enabled via VictronConnect. Go to “battery settings” and then to “Remote mode”. (see attached image)
Set the remote mode from “on/off” to “2-wire BMS”.
In this mode, the “load”, “load disconnect” or “allowed to discharge” signal and the “charger”, “charger disconnect” or “allowed to charge” signals from a Victron lithium battery BMS are used to control the unit. They respectively turn the inverter off in case discharge is not allowed, and turn the solar charger off if charging is not allowed by the battery.
Connect the BMS “load”, “load disconnect” or “allowed to discharge” terminal to the Inverter RS Smart “Remote H” terminal.
Connect the BMS “charger”, “charge disconnect” or “allowed to charge” to the unit Inverter RS Smart “Remote L” terminal.
3.9.2. Programmable relay
Programmable relay which can be set for general alarm, DC under voltage or genset start/stop function. DC rating: 4A up to 35VDC and 1A up to 70VDC
3.9.3. Voltage sense
For compensating possible cable losses during charging, two sense wires can be connected directly to the battery or to the positive and negative distribution points. Use wire with a cross-section of 0,75mm².
During battery charging, the charger will compensate the voltage drop over the DC cables up to a maximum of 1 Volt (i.e. 1V over the positive connection and 1V over the negative connection). If the voltage drop threatens to become larger than 1V, the charging current is limited in such a way that the voltage drop remains limited to 1V.
3.9.4. Temperature sensor
For temperature-compensated charging, the temperature sensor (supplied with the unit) can be connected. The sensor is isolated and must be fitted to the negative terminal of the battery. The temperature sensor can also be used for low temperature cut-off when charging lithium batteries (configured in VictronConnect).
3.9.5. Programmable analog/digital input ports
The product is equipped with 2 analog/digital input ports, they are labelled AUX_IN1+ and AUX_IN2+ on the removable User I/O terminal block.
The digital inputs are 0-5v, and when a input is pulled to 0v it is registered as 'closed'
These ports can be configured in VictronConnect.
Unused: the aux input has no function.
Safety switch: the device is on when the aux input is active.
AC IN connect: only connect to AC input when AUX input is active. An example of when this might be useful is to disable AC input grid charging during an expensive time of use tariff period.
You can assign different functions to each aux input. In case the same function is assigned to both aux inputs then they will be treated as an AND function, so both will need to active for the device to recognise the input.
3.9.6. User I/O terminal diagram
User I/O Connector is located on bottom left side of connection area, diagram shows 3 perspectives. Left Side - Top - Right Side
3.9.7. User I/O functions
Number | Connection | Description |
|---|---|---|
1 | Relay_NO | Programmable relay Normally Open connection |
2 | AUX_IN - | Common negative for programmable auxiliary inputs |
3 | AUX_IN1+ | Programmable auxiliary input 1 positive connection |
4 | AUX_IN2+ | Programmable auxiliary input 2 positive connection |
5 | REMOTE_L | Remote on/off connector Low |
6 | REMOTE_H | Remote on/off connector High |
7 | RELAY_NC | Programmable relay Normally Closed connection |
8 | RELAY_COM | Programmable relay common negative |
9 | TSENSE - | Temperature Sensor negative |
10 | TSENSE + | Temperature Sensor positive |
11 | VSENSE - | Voltage Sensor negative |
12 | VSENSE + | Voltage Sensor positive |
3.10. Programming with VictronConnect
This guide will help you with the specific elements of VictronConnect and settings that apply to your SmartSolar MPPT RS.
More general information about the VictronConnect app - how to install it; how to pair it with your device; and how to update firmware, for example - can be found by referring to the overall VictronConnect manual. A list of all VictronConnect compatible devices can be viewed here.
Note: These instructions can apply to different products and configurations, where battery voltage is referred to in these instructions, if a 12V battery is used as a reference point. Please multiply the given values by 4 to arrive at settings for an installation configured for the 48V battery system.
3.10.1. Settings
 |
The settings page is accessed by clicking on the Cog icon at the top right of the Home page. The settings page provides access to view or change the settings of the Battery; Load; Streetlight; and Port functions. From this page you can also view Product information such as the Firmware versions installed on the MPPT Solar Charger.
3.10.2. Battery settings
Battery voltage
The SmartSolar MPPT RS is fixed to 48V, and is only available for 48V systems.
Max charge current
Allows the user to set a lower maximum charge current.
Charger enabled
Toggling this setting turns the Solar Charger off. The batteries will not be charged. This setting is intended only for use when carrying-out work on the installation.
Charger settings - Battery preset
Battery preset allows you to select the battery type; accept factory defaults; or enter your own preset values to be used for the battery charge algorithm. The Absorption voltage, Absorption time, Float voltage, Equalisation voltage and Temperature compensation settings are all configured to a preset value - but can be user-defined.
Built-in preset: select of the built-in presets (Normal, High and LiFePO4 2-wire BMS)
User defined: all parameters can be customized manually
Select preset: select a type from the VictronConnect battery presets
Create preset: create a new battery preset in VictronConnect
Edit presets: edit an existing battery preset in VictronConnect
User-defined presets will be stored in the preset library - in this way installers will not have to define all the values each time they are configuring a new installation.
By selecting Edit Presets, or on the Settings screen (with expert mode on or not), custom parameters can be set as follows:
Battery Chemistry
OPzS/OPzV
Gel/AGM
Lithium (LiFePO4)
Remote Mode
Configure what is connected to the REMOTE_L and REMOTE_H inputs on the user connector.
Remote on/off: a simple on/off switch
2-wire BMS: wired BMS with allow-to-charge and allow-to-discharge signals like the SmallBMS. Note if 2-wire BMS is selected, then the unit will not start up until one is connected.
Expert mode
This on/off toggle enables editing expert settings in case your equipment has special requirements.
BMS controlled
This item is only visible in case the unit is controlled remotely by a BMS. Click to change/view, this opens a new menu, described further down in the document.
Absorption voltage
Set the absorption voltage.
Float voltage
Set the float voltage.
Equalization voltage
Set the equalization voltage.
Storage Voltage
Set the storage voltage
Re-bulk voltage offset
Set the voltage offset that will be used over the float voltage setting that will determine the threshold that the charge cycle will restart.
E.g.: For a Re-bulk voltage offset off 0.4V and a float voltage setting of 54.0 V, the voltage threshold that will be use to restart the charge cycle will be 53.6 V. In other words, if the battery voltage drops below 53.6 V for one minute, the charge cycle will restart.
Adaptive absorption time
Select with adaptive absorption time or fixed absorption time will be used. Both are better explained below:
Fixed absorption time: The same length of absorption is applied every day (when there is enough solar power) by using the maximum absorption time setting. Be aware that this option can result in overcharging your batteries, especially for lead batteries and system with shallow daily discharges. See your battery manufacturer for recommended settings. Note: make sure to disable the tail current setting to make the same absorption time every day. The tail current could end absorption time sooner if the battery current is below the threshold. See more information on the tail current setting section below.
Adaptive absorption time: The charge algorithm can use an adaptive absorption time: it automatically adapts to the state of charge in the morning. The maximum duration of the absorption period for the day is determined by the battery voltage as measured just before the solar charger begins operation each morning (12 V battery values used - Multiply Battery voltage by 4 for 48V ):
Battery voltage Vb (@start-up) | Multiplier | Maximum absorption times |
|---|---|---|
Vb < 11.9 V | x 1 | 06:00 hours |
> 11.9 V Vb < 12.2 V | x 2/3 | 04:00 hours |
> 12.2 V Vb < 12.6 V | x 1/3 | 02:00 hours |
Vb > 12.6 V | x 2/6 | 01:00 hours |
The multiplier is applied to the maximum absorption time setting and this results in the maximum duration of the absorption period used by the charger. The maximum absorption times shown in the last column of the table are based on the default maximum absorption time setting of 6 hours.
Maximum absorption time (hh:mm)
Set the absorption time limit. Only available when using a custom charge profile.
Enter the time value in the notation hh:mm, where hours are between 0 and 12; and minutes are between 0 and 59.
Tail current
Set the current threshold that will be used to finish absorption phase before the maximum absorption time expires. When the battery current gets below the tail current for one minute, the absorption phase will end. This setting can be disabled by setting it to zero.
Equalization current percentage
Set the percentage of the Max charge current setting that will be used when equalisation is performed.
Automatic Equalization
Set-up the frequency of the auto equalize function. Available options are between 1 and 250 days:
1 = daily
2 = every other day
...
250 = every 250 days
Equalization is typically used to balance the cells in a lead battery, and also to prevent stratification of the electrolyte in flooded batteries. Whether (automatic) equalization is necessary, or not, depends on the type of batteries, and their usage. Consult your battery supplier for guidelines.
When the Automatic equalization cycle has initiated, the charger applies an equalization voltage to the battery as long as the current level stays below the equalization current percentage setting of the bulk current.
Duration of the Automatic equalization cycle
In the case of all VRLA batteries and some flooded batteries (algorithm number 0, 1, 2 and 3) automatic equalization ends when the voltage limit (maxV) has been reached, or after a period equal to (absorption time/8) - whichever comes first.
For all tubular plate batteries (algorithm numbers 4, 5 & 6); and also for the user-defined battery type, automatic equalization will end after a period equal to (absorption time/2).
For the Lithium battery type (algorithm number 7), equalization is not available.
When an automatic equalization cycle is not completed in one day, it will not resume the next day. The next equalization session will take place according to the interval set in the 'Auto Equalization' option.
The default battery type is a VRLA battery and any user-defined battery will behave as a tubular plate battery with regard to equalization.
Equalisation stop mode
Set how the equalisation will end. There are two possibilities, first is if the battery voltage reaches the equalisation voltage and the second is on fixed time, where the maximum equalisation duration is used.
Maximum equalisation duration
Set the maximum time that the equalisation phase will last.
Temperature compensation
Many types of battery require a lower charge voltage in warm operating conditions, and a higher charge voltage in cold operating conditions.
The configured coefficient is in mV per degree Celsius for the whole battery bank, not per cell. The base temperature for the compensation is 25°C (77°F), as shown in the chart below.
With a temperature sensor installed to the User I/O connection block; the actual battery temperature will be used for compensation; throughout the day.
Low temperature cut-off
This setting can be used to disable charging at low temperatures as required by Lithium batteries.
For Lithium Iron Phosphate batteries this setting is preset at 5 degrees Celsius, for the other battery types it is disabled. When creating a user defined battery the cut-off temperature level can be adjusted manually.
Manual Equalization - Start now
Selecting 'Start now' on 'Manual equalisation' allows manual initiation of an Equalization cycle. To allow the charger to equalize the battery properly use the manual equalize option only during absorption and float periods, and when there is sufficient sunlight. Current and voltage limits are identical to the automatic equalize function. The duration of the equalisation cycle is limited to a maximum of 1 hour when triggered manually. Manual equalization can be stopped at any time by selecting 'Stop Equalize'.
3.10.3. Programmable relay
 |
A programmable relay switch is available on some SmartSolar models. The datasheet for your model will tell you whether or not it is available.
The relay offers three connections:
NO (Normally Open)
C (Common)
NC (Normally Closed)
Relay state | Connection between |
|---|---|
Switched ON | C and NO |
Switched OFF | C and NC |
The conditions for switching the relay depend on the relay mode setting, note that the conditions for switching over must be present for at least 10 seconds before the relay will change position.
Relay mode
Relay always off. This option switches the relay OFF. It will disable the other relay options. Use this option if you do not plan to use the relay function.
Panel voltage high. This option switches the relay ON when the panel voltage becomes too high. See Panel voltage high mode settings below.
High temperature (Dimming). This option switches the relay ON when the charger output current is reduced due to high temperatures. Use this option to for example switch an external fan.
Battery voltage Low. This option switches the relay in ON when the battery voltage falls too low, see Battery voltage Low settings below. This is the default setting when the relay function is active.
Equalization active. This option switches the relay ON when the manual equalization mode is active.
Error state. This option switches the relay ON when there is an error.
Defrost option (Temp < -20 °C). This option switches the relay ON when the Charger temperature falls below -20 degrees Centigrade.
Battery voltage high. This option switches the relay ON when the battery voltage is too high, see Battery voltage High settings below.
Float or Storage state. This option switches the relay ON when the charger is in the float state.
Day detection (Panels irradiated). This option switches the relay ON whilst the solar panels are providing energy (Day/Night detection).
Panel voltage High settings
Panel high voltage. (User-defined Voltage)
Clear panel high voltage. (User-defined Voltage)
This option switches the relay ON when the panel voltage rises above the chosen “Panel high voltage” setting, and switches the relay OFF when the panel voltage falls below the chosen “Clear panel high voltage” setting. Ensure, of course, that the “Panel high voltage” setting is greater than the “Clear panel high voltage” setting. These settings must never exceed the maximum voltage-rating allowed by your MPPT charger.
Battery voltage Low settings
Battery low-voltage relay. (The default setting for this is 10.00V) (12V battery assumed)
Clear battery low-voltage relay. (The default setting for this is 10.50V)
These settings, which can be user-defined, will cause the relay to switch ON when the battery voltage falls below the chosen “Battery low-voltage” setting; and will cause the relay to switch OFF when the battery voltage once again rises above the “Clear battery low-voltage” setting. Ensure, of course, that the “Battery low-voltage relay” setting is lower than the “Clear battery low-voltage relay” setting.
An application for this feature, for example, is to automatically disconnect a load in order to prevent a battery from becoming too deeply discharged.
Battery voltage High settings
Battery high-voltage relay. (The default setting for this is 16.50V) (12V battery assumed)
Clear battery high-voltage relay. (The default setting for this is 16.00V)
These settings, which can be user-defined, will cause the relay to switch ON when the battery voltage rises above the “Battery high-voltage relay” setting; and will cause the relay to switch OFF when the battery voltage drops below the “Clear battery high-voltage relay” setting. Ensure, of course, that the “Battery high-voltage relay” setting is greater than the “Clear battery high-voltage relay” setting.
An application for this feature, for example, is to disconnect a load in order to protect it from an over-voltage.
General settings
Minimum closed time. (The default setting for this is 0 minutes)
This option sets a minimum-time for the ON condition to prevail once the relay has been switched ON.
An application for this feature, for example, is to set a minimum generator run-time.