Isolated SmartSolar MPPT RS

The SmartSolar MPPT RS will test for sufficient resistive isolation between PV+ and GND, as well as PV- and GND. If the resistance falls below the threshold, the unit will report an error and send an error signal to the GX device (if connected) for audible and email notifications. Despite the error, the product will continue charging the battery.

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 properly configured VRM account.

The positive and negative conductors of the PV array must be isolated from ground.

Ground the frame of the PV array according to local regulations. Use the ground lug on the chassis to connect the unit to the common earth.

The grounding conductor from the chassis ground lug to the earth must have a cross-section at least equal to that of the PV array conductors.

When a PV resistance isolation fault is indicated, do not touch any metal parts. Contact a qualified technician immediately to inspect the system for faults.

The battery terminals are galvanically isolated from the PV array, ensuring that PV array voltages cannot transfer to the battery side of the system in the event of a fault.

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:

See table for MINIMUM battery and cable requirements.

Use a torque wrench with insulated box spanner in order to avoid shorting the battery. Maximum torque: 14 Nm Avoid shorting the battery cables.

To access the battery terminals, undo the two screws at the bottom of the enclosure and remove the cover to expose the service compartment.

The battery terminals for the MPPT RS 450/100 are located on the left-hand side of the wiring compartment. Remove the nut, spring washer, and flat washer before attaching the cable terminal lug. Note: The bottom nut is soldered to the PCB; do not attempt to loosen it.
The battery terminals for the MPPT RS 450/200 are located on the left-hand side of the wiring compartment. There are two studs each for the positive and negative terminals, allowing for the doubling up of battery cables. Remove the nut, spring washer, and flat washer before attaching the cable terminal lug.

It is important to place the terminal lug onto the stud first, followed by the flat washer, spring washer, and nut, in that order. Ensure that each nut is tightened to a maximum torque of 14 Nm.

The SmartSolar MPPT RS is not fitted with a PV disconnect switch. An appropriately rated DC disconnection swich must be installed between the PV array and the SmartSolar MPPT RS.

Mount the PV disconnection switch in a readily accessible location.

The MPPT RS 450/100 and the MPPT RS 450/200 Solar charge controllers feature MC4 connectors located on the bottom of the unit. These connectors are pre-wired, so the bottom cover does not need to be removed to connect the PV cables.

The MPPT 450/100 is equipped with two pairs of MC4 connectors, one male and one female per tracker.

The MPPT 450/200 is equipped with four pairs of MC4 connectors, one male and one female per tracker.

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.

The SmartSolar MPPT RS is built using Staubli MC4 connectors. There are many other brands available, but some manufacturing variations mean that they may make poor contact and cause excessive heat. There are also inferior brands on the market which will likely cause problems.

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 16 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.

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.

Table 1. PV Array Example

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

Figure 2. MPPT RS PV example diagram

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).

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.

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:

https://www.victronenergy.com/live/ess:start