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Detailed reviews and information of the best solar panels, inverters and batteries. Plus hybrid and off-grid solar system reviews and information articles on how solar and battery systems work.

Selectronic SP PRO - Hybrid off-grid Inverter Review

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Selectronic SP PRO - Hybrid off-grid Inverter Review

Jason Svarc

Background

Selectronic based in Melbourne Australia recently celebrated its 50th birthday, for this and many other reasons it is unlike any other manufacturer in the solar industry. The team at Clean Energy Reviews met with the Director of Marketing, Rod Scott, who showed us around the company’s headquarters and manufacturing facility in Melbourne.

Selectronic manufacture a range of sophisticated multi-mode battery inverters which are available in a variety of sizes for off-grid and on-grid residential and commercial applications.

To say Selectronic is modest is an understatement, the company has developed what is possibly the most advanced grid-interactive/off-grid inverter in the world with a relatively small team of engineers and exports to countries all over the globe including Germany which is generally known for manufacturing the best solar equipment. Despite this Selectronic is not a huge name outside the solar industry, even in it’s home country Australia. The reason is that they focus on a specific area which is providing high-end, energy storage inverters.

Selectronic does not manufacture solar inverters but rather a range of multi-mode inverters called the SP PRO which are designed to be used in both off-grid and on-grid battery installations where energy storage and power management is required. However it is capable of so much more using possibly the most advanced software of any inverter on the market today.

NOTE: the Selectronic SP PRO is available in most overseas markets, except the United States.

What is the SP PRO?

Before we go into detail about the SP PRO, let's be clear about exactly what it is and what it does. The SP PRO is essentially an advanced on-grid or off-grid battery inverter/charger. But where it really shines is when it comes to energy management due to the flexible software which drives it. The SP PRO can be setup as one or more of the following systems:

  1. Grid connected battery backup system (UPS)

  2. Hybrid solar energy storage system

  3. Stand-alone (off-grid) power system

  4. Commercial energy management system

There are also various configuration options such as an AC or DC coupled with one or more solar inverters/controllers which can be used to built modular solar energy storage system/s. Plus the SP PRO can function as a commercial energy management system to reduce peak loads (peak lopping). To top it off it can also be used to retrofit or add batteries to existing grid-connected solar installations.

Battery Options

The SP PRO range was originally designed for use with deep-cycle lead-acid battery banks of all varieties - flooded, sealed, Gel or AGM, and voltages of either 24V, 48V or 120V. In order to accurately monitor and charge deep cycle battery systems Selectronic developed a range of advanced battery sensors into the SP PRO to ensure accurate charging such as features like mid-string monitoring which can also detect faults in batteries strings.

Compatible Lithium batteries

Recently new generation high performance Lithium battery systems have taken over much of the market and the SP PRO is compatible with many of the leading brands including LG chem, BYD and Sonnenschein. Lithium battery systems contain a BMS (battery management system) which must be compatible with the SP PRO and pass-on battery state of charge and other data in order function correctly, increase battery life and maintain the correct charge/discharge rates.

The SP PRO is also able to function with ‘unmanaged’ lithium batteries, these are batteries which operate independently, ie the battery BMS takes care of the battery and does not need to communicate data to the SP PRO (However the SP PRO still must be programmed with the correct settings to match the battery). Such batteries include the Simpliphi PHI range and GenZ rack mount LFP battery modules.

 Compatible lithium batteries certified to use with the SP PRO for on-grid and off-grid installations

Compatible lithium batteries certified to use with the SP PRO for on-grid and off-grid installations

Selectronic SP PRO is also one of the few inverters which is compatible with the very new super capacitor energy storage systems such as those from KiloWatt Labs.

Powerful off-grid Solar system

In Australia the SP PRO is regarded among solar designers and installers as the leading inverter for off-grid or stand-alone solar power systems. The huge surge power output, advanced sensors, clever monitoring, AC / DC coupling capability and multiple battery options available including lithium and lead-acid make it the first choice for any serious off-grid installation.

It is so popular solar cutters around Australia have dubbed the AC coupled combination of the SP PRO and leading Fronius solar inverter and the 'Spronius' which basically translates to unbeatable quality, power and features.

 

Hybrid Inverters Vs SP PRO Inverter

So how the does the SP PRO compare with the new hybrid battery inverters and energy storage systems on the market, the most common being the all-in-one inverters which manage both the solar and battery charging on one unit?

Cheaper all-in-one hybrid inverters while simple and compact do have several limitations, the main drawback being the limited loads or appliances which can be powered by the unit and this is one area where the SP PRO really shines.

 The SP PRO compared to many of the well known hybrid and off-grid inverters - Click for Technical guide

The SP PRO compared to many of the well known hybrid and off-grid inverters - Click for Technical guide

Unlike most hybrid inverters the SP PRO is unique in that it can pass through additional power from the grid or a back-up generator (or both) and has the highest pass through power capacity of any inverter on the market at 63A or 15kW. This means that in most applications the entire home or business can be managed and backed-up by the inverter where as with the all-in-one hybrid inverters only selected small loads or circuits can be backed up. Also unlike many all-in-one inverters which have had multiple software issues and bugs the SP PRO is one of the most trusted and reliable products on the market.

 Typical configuration of an AC coupled system

Typical configuration of an AC coupled system

The SP PRO can be both AC and DC coupled which means the solar capacity can be easily expanded if required by coupling additional solar inverters or DC controllers. This also gives much greater flexibility in how the battery is used, especially if there are both DC and AC loads.

Cost Vs Features - If you are looking to install a simple battery system for self use and limited backup power, or if you are on a very tight budget a common all-in-one hybrid inverter will be a more economical option. See our guide to selecting an off-grid or hybrid inverter here.

 

Commercial Applications

The SP link monitoring and programming software

The SP PRO is generally the product of choice for high end off-grid and hybrid systems but for the larger commercial solar with battery backup situations it does have one main limitation, this being that it is not capable of coupling more than one inverter per phase (Although we have been told this capability is on the development roadmap). At present the largest SP PRO has a huge 20kW continuous output per phase which is very high and more than adequate for many commercial installations. In addition the SP PRO can AC couple solar PV at double it's rated capacity, so a 20kW inverter can manage up to 40kW solar array. With a large 60kW 3-phase system this equates to massive 120kW of solar with additional solar able to be added through DC coupling if required.

Off grid dairy farm powered by 3 x SP PRO's AC coupled with 60kW solar

This is a powerful product designed to manage a wide range of power sources and supply very high continuous loads to ensure uninterruptible power supply (UPS) whether you are completely off the grid, connected to an unreliable electricity grid, or want an emergency power supply in the event of the occasional black out or natural disaster. The huge surge load capability and optional external pass through power capability (up to a huge 60kW or 250A per phase) of the SP PRO inverters make it applicable for wide variety of installations.

Advanced Software and Monitoring

SP Link data log 2

SP-Link software - One of the many configuration pages

Our solar specialists who have installed hundreds of hybrid and off-grid energy storage systems consider the stand out feature of the SP PRO as the programmable software package. Having a robust and reliable grid-interactive or off-grid inverter is great but it is the software which is really responsible for controlling the system. Selectronic's software called SP-Link is a free, customisable software package which includes some 220+ settings to enable complete control. This is particularly important with the many new battery technologies on the market which require unique charge settings and monitoring. Another bonus which is often overlooked by many manufactures is backwards compatibility. All new software and firmware upgrades released by Selectronic are compatible even with the first model SP PRO released in 2008. And to keep up to date in the world of mobile monitoring Selectronic will soon be releasing the SP-Link mobile app later in 2016.

 

New for 2018

About the only weakness of the SP PRO was the difficulty setting up remote monitoring through the old gateway and the lack of a smart phone app to remotely monitor the SP PRO in real time.

To address this Selectronic recently released a low cost add-on device called the Select.live which is a small communication unit which uses a cloud portal to monitor your system from any where in the world in real time. This system provides an abundance of information about your system/s and energy consumption and provides easy to read graphs and systems status information.

 

Additional Features

The deeper you look into the SP PRO the more features you seem to find, incorporating 4 relay outputs for controlling loads to the multiple digital inputs and outputs it can used much like a computer PLC controller. Then there are the unique features like mid-string monitoring used for warning the if there is a faulty cell in a large battery bank (lead-acid gel or AGM), a feature which no other inverter on the market currently has built-in. This really goes to show what a relatively small company can achieve when it focuses on developing a core product.

 INSIDE THE SP PRO - AC & DC Connections

INSIDE THE SP PRO - AC & DC Connections

Wrap up - Summary

The Australian made Selectronic SP PRO inverters really speak for themselves as there are many 20+ year old off-grid installations around the world still working with the older generation Selectronic battery inverters. The high quality proven design, advanced monitoring features and flexibility in both AC & DC coupling make this one of the best inverters on the market today. In addition the high surge power ouput, leading pass-through power rating, clever software and compatibility with leading lithium and VRLA batteries give the SP PRO a list of features far greater than the best European or US made inverters.

If you are looking to install a serious quality off-grid or hybrid installation then the SP PRO series would be hard to pass by, the price may be premium but when you are managing battery storage systems worth many thousands then it is easy to justify.

See the full SP PRO Specifications here

For more information about solar hybrid and off-grid systems see our Hybrid/off-grid Inverter and solar energy storage review