Get Connected: Best practices for eliminating PV connector failures

A cross-mating issue. Example via Staubli.

PV connectors play a crucial role in the wiring of solar arrays. As designed and if correctly installed, they provide a high-voltage, high-current, low-resistance DC connection in a housing that is water-tight, temperature-resilient, UV and wire-pull-resistive over the 25-year-plus life of the solar installation. In addition, their snap- together connection technology speeds installation of solar arrays. They are, however, often a source of array failures.

A study by the Fraunhofer Institute for Solar Energy Systems ISE of Freiburg, Germany, examined the causes of thermal failures of PV arrays and found that PV connectors and crimps were the largest single cause of DC wiring failures. Most of these failures occurred during the first five years of installation, leading researchers to suspect poor installation practices as a primary cause.

Discussions here in the United States with electrical inspectors have also yielded the following insights into PV connector failures:

  • Poor contact crimps or crimps that have grabbed some of the wire insulation
  • Contacts that were not installed correctly into the connector, causing high-resistance connections
  • Water intrusion due to improperly assembled connectors

Several inspectors have also observed field installers crimping PV connectors’ contacts with pliers. Additional comments highlighted the “loose” fit of PV connectors of different manufacturers.

Compounding the array failures of PV connectors is that it can be difficult to see improper assembly and poor contact crimps. Connection failures are often hidden within a seemingly acceptable connector. Outside of a complete failure, such as a distorted or melted connector, visual detection is nearly impossible. Thermal imaging is often the only way to detect these problems. The energy loss, diagnostics and repair costs associated with hidden failures can be significant.

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Sources of PV connector failures

PV connector failures can be categorized into two areas: incompatibility issues and connector wiring problems. Most of these failures are associated with field wiring. Factory-installed connectors found on the back of PV modules are usually not a significant source of problems. However, field-installed connectors such as those for home-run string end cabling used with string and other central inverters can be problematic.

Incompatibility issues are often caused by the mating of PV connectors from different manufacturers. While many connectors are considered “compatible,” there is no industry standard for a uniform connector design. Due to the differences in design tolerances, crimp tool requirements and contact and housing materials, optimal electrical connection cannot be guaranteed. In addition, while all PV connectors should be tested to UL 6703, this standard does not cover the mating of connectors from different manufacturers unless specifically tested — something rarely done. Some manufacturers caution against the mating of different connector brands, and the recommended practices should be followed.

Most PV connectors use crimp-style contacts. Whether factory- or field-installed, these connectors require the manufacturer-recommended crimp tool and proper assembly for a trouble-free installation. Crimp tool calibration requirements and crimp die limits must be adhered to for trouble-free installation over the lifetime of the array. New tool-less PV connectors are now available as well. These connectors eliminate the tooling and assembly requirement, but they use a temperature- and vibration-resistant spring contact for wire connections.

Best practices for PV connector installation

The solution to the challenges of PV connector failures is to ensure the correct installation during the initial wiring of the array. Some best practices that can be used to accomplish this are:

  • Proper training of installers on PV connector assembly
  • Use of the proper crimp tools, calibration and methods recommended by the PV connector manufacturer
  • The use of tool-less spring contact PV connectors, eliminating the crimping requirements

Beyond the challenge of correct PV connector assembly is the issue of incompatible PV connector mating. Best practices in this area include always specifying the same brand of field connector as that supplied by the PV module manufacturer. This includes the use of microinverters and optimizers. Some of these manufacturers are making this easier in some cases by offering a choice of PV connector brands on their equipment.

The use of PV connectors from the same manufacturer, proper training, recommended crimp tools or the use of a tool-less spring contact PV connectors can help minimize the impact of connector failures.

Dan Sylawa is senior business development manager for Phoenix Contact.

— Solar Builder magazine

Chint Power Systems is integrating Pason Power into its Energy Storage System for C&I solar installers

CPS America

Chint Power Systems (CPS) has chosen Pason Power’s software to be integrated into its Energy Storage System as the exclusive platform for commercial and industrial (C&I) customers.  This integrated energy storage solution fosters a simplified, single-source procurement process for customers rather than having to rely on multiple vendors. Casey Miller, Vice President of Products and Strategy at CPS says Pason Power’s adaptive software completes the turnkey offering from CPS.

“After evaluating a number of software platforms, we chose Pason Power because of its capable platform, its ability to maximize ROI in a changing energy environment, and most importantly the backing of a company with decades of experience in data management for the energy industry,” said Miller. “With our hardware and Pason Power’s software solution, we have been able to significantly reduce the complexity and risk of executing small commercial storage for our customers. We have what we believe to be the best small commercial solution for solar, and we now have energy storage solution that can help project developers grow their business.”

Also cool: hardware and software will arrive pre-built and pre-configured, making it easy for developers to install so customers can quickly begin seeing the benefits. By pre-integrating with CPS’s energy storage solution, Pason Power’s platform can accurately model anticipated operating parameters, yielding more precise results.

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“As C&I energy and sustainability managers seek greater control over their energy use, interest in energy storage is skyrocketing,” said Ricardo Rodriguez, research analyst at Navigant Research. “To unlock the next level of value in the C&I storage market, stakeholders are exploiting cumulative advances in software and analytics to enable the bundling of grid applications to stack up multiple value streams. Balancing this complexity will require sophisticated analytical and system control capabilities to ensure an energy storage system provides maximum value and maintains peak performance for as long as possible.”

“The integration of the Pason Power platform with the CPS systems gives customers the ability to confidently size, procure, and install intelligent energy storage systems, while also providing faster delivery times and cost certainty,” said Enrico Ladendorf, Managing Director of Pason Power. “The combined system enabled by our software platform can help solar installers and project developers grow their businesses by delivering more accurate estimates on project financial performance such as IRR, Payback Period, and NPV.”

More on Pason Power

Pason Power’s intelligent software platform is designed to unlock value from each phase of the energy storage project lifecycle. It delivers predictable and reliable results that give confidence to developers, financiers, utilities, and operators when deploying and managing energy storage assets

“The platform offers a clear view into every step of the procurement and deployment process, including visibility into the real-time performance and aggregated savings of the system,” Ladendorf says. “This significantly lowers project risks by optimizing the energy storage system to a customer’s unique and specific power needs.”

The CPS Energy Storage Systems are designed for demand charge reduction, time of use shifting, PV self-consumption, and back-up power applications. Available in 30kW/65kWh or 60kW/ 130kWh solutions, these turnkey UL 9540 certified systems are available and ready to meet customer demand today.

— Solar Builder magazine

Solar PV Inverter Buyer’s Guide 2019: Faster installs, better serviceability and a focus on storage

2019 inverter buyer's guide web banner

The 2019 solar inverter market is more robust and reliable than ever. From streamlined residential operations to beefed up large-scale string inverters to a cadre of solar+storage options for both on- and off-grid applications, there are products to match any solar PV design need. We reached out to every inverter manufacturer to hear about their latest innovations and to share some advice for installing their systems efficiently. All of those are below, starting with residential on through storage, commercial and finally utility-scale.

Residential solar inverters

Fronius | SnapINverter: Primo

Flexible system design, easy installation, integrated Wi-fi

Fronius Primo

The Fronius SnapINverter line offers integrated Wi-Fi and SunSpec Modbus interfaces, NEMA 4X rating, wide voltage windows, multiple MPP trackers and easy installation in 15 minutes or less. Power classes range from 3.8 kW to 24 kW, but with an identical look and feel combined with unique field-serviceability, Fronius SnapINverters reduce the costs for training and servicing. All Fronius SnapINverters offer wide voltage windows for easy system design. The Fronius Primo is available up to 15 kW, making it the biggest single-phase inverter available, offering the most flexible string sizing with string length as short as two or three modules (80 V startup voltage). It also allows for inverter oversizing of up to 150 percent within warranty.

Install advice: Few tools are needed to complete a Fronius inverter installation, but the most important tool in our opinion is a torque screwdriver. Using this tool and paying attention to the provided torque specifications of the inverter will always ensure a safe and optimal installation.

Monitoring: Free lifetime monitoring comes standard with Fronius and Solar.Web. In it, you can check the performance of a system in addition to performing remote updates. The Fronius Datamanager is included in all of the Primo inverters. This piece of hardware is the communications center for Fronius inverters for all applications. Whenever it is connected to the internet via a LAN or Wi-Fi, the Fronius Datamanager sends the PV system values directly to Fronius Solar.web to provide an overview of how the system is operating at all times.


Click here for full spec document

APsystems | The QS1

Can reduce installation time by 75 percent 

The QS1 is a four-module, single phase microinverter that doesn’t cost the equivalent of four individual microinverters either. The shared components reduce the overall cost per Watt in comparison with conventional microinverters.
On the technology side, the QS1 delivers the highest output power among microinverters today at 300 W per channel, can accommodate PV modules up to 375 W and has a 22V-48V voltage range. It also features four individual MPPT so each PV module is managed and tracked separately. The QS1 employs high-speed wireless Zigbee, which is up to three times faster than conventional powerline communication (PLC), creating a local 2.4 GHz mesh network for fast and reliable data communication between the microinverters and the gateway. The QS1 utilizes a common AC trunk cabling with the APsystem’s dual-module YC600, which means both microinverters can be deployed on the same circuit for better site design capability and to maximize circuit capacity. Because the QS1 tracks better through this voltage range at dawn and dusk, it gets the most out of the available sunlight, even in those lower light conditions, maximizing the energy harvest for the homeowner.

Install advice: We recommend that installers use a direct Ethernet connection from the gateway to the homeowner’s router. Even though Wi-Fi is an available function, a direct line is more reliable in instances when the homeowner changes ISPs or passwords. This will save the installer returns to the jobsite for IT issues.

Monitoring: APsystems’ EMA monitoring is a multiple-level, cloud-based platform that provides installers with detailed access to their installed projects, including module-level monitoring and analysis. Homeowners, likewise, can see module-level detail as well as a more comprehensive overview of site performance and health, all at no cost.

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Full spec document

SMA America | Power+ Solution

A proactive service solution to decrease truck rolls and system downtime.

Power+ solution-sma

SMA’s improved Power+ Solution builds on the company’s MLPE solution to provide even more speed and simplicity. The UL-listed Power+ Solution is one of the fastest residential PV systems to install. One of the most significant improvements to the Power+ Solution is a major reduction in system components within a new Rooftop Communication Kit, meaning fewer potential points of failure throughout the system and less equipment to service. Additionally, a single plug-and-play communication connection speeds installation and reduces labor. The new Power+ Solution offers 50 percent faster commissioning within Sunny Portal.

Install advice: SMA offers a useful YouTube library of Tech Tip videos for time saving instructions on the installation and commissioning of the Power+ system, including registration on Sunny Portal.

Monitoring: Power+ systems can be registered for free on SMA’s Sunny Portal, allowing module level monitoring of the whole system. Registration with Sunny Portal, the PV industry’s largest monitoring site (according to GTM Research, Oct 2017), allows installers to opt into the free Smart Connected service. Sunny Portal can be accessed via computer or smartphone app.


Full spec document

Ginlong Solis | MLRSD

One rapid shutdown device for every two modules


The R&D Team at Solis HQ has created a new module-level rapid shutdown device (MLRSD) for the North American PV market. This new device meets all requirements of NEC 2017 Article 690.12 and is listed to the UL1741 (SA) and UL 991 Test Standards. Installers need only carry one Solis MLRSD for every two PV modules on the roof. Each Solis MLRSD device has dual inputs (for two 370 W max PV modules) and two PV Wire interconnection whips (MC4) for connecting the MLRSD’s together on the roof. The enclosure is rated NEMA 4X with an IP68 ingress rating. The enclosure is non-metallic and does not require grounding. An integrated mounting plate can be used to secure the unit to the PV modules or support rack. The MLRSD features a self-test, fault detection LED indicator. Solis residential PV inverters include an integrated, multi-channel PLC signal generator that can control as many as four (4) separate PV strings equipped with Solis MLRSDs.

Install advice: The Solis MLRSD utilizes MC4 connectors. An installer must make sure the connectors are fully inserted. Full, complete connection will ensure that the inverter does not detect a partial connection and post an Arc Fault Alarm message (series fault).

Monitoring: Solis Inverters can be connected to the Ginlong Solis web-based monitoring solution called Ginlong Monitoring. Solis inverters can be connected to a local router using the Solis Wi-Fi stick or connected to a local mobile phone tower using the Solis Cellular Stick. The owner/operator can get most information off the LCD screen at the inverter but data from each MPPT and all AC and DC production data is available on a friendly dashboard where owners can check current conditions and maintenance techs can review history performance and alarm code histories.


Full spec document

SolarEdge | EV Charging Inverter

Six times faster than a Level 1 EV charger, using grid and PV simultaneously

solaredge ev charger

SolarEdge’s EV charging single-phase inverter is the world’s first EV charger with an integrated PV inverter. It enables homeowners to charge electric vehicles up to six times faster than a standard Level 1 charger through its innovative solar boost mode that utilizes grid and PV charging simultaneously. Reducing the hassle of separately installing a standalone EV charger and a PV inverter also means eliminating the need for additional wiring and conduit. By installing an EV charger that is integrated with an inverter, no additional dedicated circuit breaker is needed, saving space and ruling out a potential upgrade to the main distribution panel.

Install advice: When installing a PV system that will serve as a source of EV charging either immediately or in the future, be sure to factor in the additional power that will be required. In order to offset the increased electricity consumption by the EV, recommend a system size that is 3-4 kWp larger than a PV system that will not be used to charge an EV. By installing a larger system in advance, the homeowner saves on future installation costs, while the installer improves its ASP.

Monitoring: SolarEdge’s monitoring platform is free for 25 years. From a computer or a phone, homeowners are able to can smart-schedule for use with Time of Use (TOU) rates; track PV, EV, and grid consumption; control household energy usage; remotely control charging; view charging duration, charge energy, and percent charge from PV.


Full spec document

Enphase | Panasonic N330E HIT with Enphase IQ 7X

All-in-one smart panel for easier installations

panasonic enphase

Enphase seems to be in every AC module you find. Its most recent partnership with Panasonic on the HIT AC Series Module combines the efficiency of HIT solar panels with the intelligence of Enphase microinverters. An Enphase IQ 7X microinverter with Individual MPPT tracking (Module-level Power Point Tracker) is integrated with HIT high efficiency solar technology to deliver maximum power production. The AC Series alternative energy source offers extreme efficiency and high power output for residential solar systems. Panasonic solar panels are backed by a performance warranty that guarantees minimum power output of 90.76% after 25 years.

Install advice: The Enphase IQ 7X recesses into the frame of the AC Series Module, saving storage space, reducing trips up the ladder, and simplifying the purchasing process.

Monitoring: With the Enphase Enlighten mobile app, you can check your system’s status at-a-glance without scrolling and still dive into the details of your system’s health and performance, all while on-the-go. One tap takes you to energy production graphs and overviews of your energy consumption and storage (if applicable).

Full spec document

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Solar+Storage inverters

CPS America | 60-KW ESS storage solution

 Full ESS solution with full warranty and bankable performance guarantee

CPS turnkey energy storage


The Energy Storage Systems (ESS) for the North American market is designed for demand charge reduction, peak shaving and time of use shifting applications. These turn-key grid connected systems are a perfect fit for smaller commercial storage needs. ESS SW solution from its partner Pason Power, including upfront cash flow analysis from the Storage Architect platform and ongoing performance management, forecasting and control via the Intelligent Energy Management System (iEMS). It is UL 9540 listed for plug and play operation and Rule 21 certified for use in California with SGIP applications. Outdoor rated with complete climate control.

Monitoring: All CPS inverters, 3 phase or 1 phase, ship standard with Modbus RS485 communications. Our communication equipment uses industry standard Modbus protocol. The CPS Flex Gateway is a data communications and controls solution for the CPS inverter line. The gateway acts as a Modbus master data logger and gateway solution for communications and controlling commercial and utility scale inverter applications. This enables three parallel outbound communications options:

(1) Local pass-through Modbus data to 3rd party solutions,
(2) Ethernet based communications to CPS Service for remote diagnostics and updates,
(3) and a programmable Ethernet XML SunSpec Data Exchange connection for customers who want to manage their data directly.


Full spec document

Morningstar | Multiwave

The benefits of both low- and high-frequency topology

Morningstar Multiwave

With no transformer or cooling fans and fewer magnetics, the Multiwave is less cramped on the inside, making O&M simple.

Morningstar’s new MultiWave 4-kW inverter/chargers combine high-frequency (HF) power conversion with advanced, two-step voltage transformation circuitry, reducing circuit complexity while maintaining high surge capacity. It surpasses low-frequency (LF) performance with the advantage of being a HF inverter design. Precise cycle-by-cycle software controls for a pure sine wave AC, maximizing load starting capability and minimizing component stresses. It is truly bi-directional topology — its rated continuous inverter power equals its rated charger power and equivalent charging efficiency. LF designs often have different power paths for inverting and charging with much lower efficiency for charging. Morningstar over-spec’d components to achieve a hardware failure rate of less than 0.4%. And like all Morningstar products, it has superior thermal design. Morningstar has never used fans to cool high-power electronics.

Install advice: For the North American market, the pre-wired BOS models can cost less than comparable pre-wired inverter/charger electric panel systems that are often offered by dealers. The pre-wiring is designed to make an NEC code compliant installation quick and easy for up to two MultiWave Inverters combining the BOS model with a standard model.

Monitoring: Morningstar’s new Envision Cloud Service allows you to remotely collect data from all the sites you need to manage. Set up with Morningstar’s Ethernet MeterBus Converter (EMC-1), it is completely scalable for large mesh networks or site clusters.


Full spec document

Outback Power | SkyBox True Hybrid Energy System

Can manage non-export, demand charge and TOU functions, regardless of which loads need backed up

Outback Skybox

The SkyBox True Hybrid Energy System provides the latest battery backup and energy management features in an easy-to-install, fully automated package that makes homes more resilient in the face of an unpredictable grid. SkyBox works with virtually any 48 VDC battery from traditional lead acid to lithium-ion and other advanced chemistries. Since the PV input is rated for 600 VDC, string sizing is similar to common grid-tie inverters – making retrofits easy. Designed for high-volume grid-tied solar PV installers who are new to energy storage, SkyBox provides simple integration with easy-to-identify terminals for Grid, Protected Loads, Battery, PV and Generator. The full-color touch screen walks users through set up for backup, non-export, time-of-use, demand-charge mitigation or all of the above.

Install advice: Popular batteries can be selected from a drop-down to streamline setup or custom settings can be used to accommodate others. SkyBox can even be installed without a battery and additional inverters and batteries can be added later.

Monitoring: SkyBox is integrated with OutBack’s OPTICS RE telemetry system for remote monitoring and full control. OPTICS allows installers and owners to keep an eye on system performance across their fleet and adjust settings remotely via the Internet.


Full spec document

Pika Energy | X7602  and X11402 Islanding Inverters

Easily integrates storage in light commercial settings with 208 V three-phase service

Pika’s Islanding Inverters use a patented DC bus technology called REbus to seamlessly control solar and storage on the same inverter. With REbus, bus voltage and powerline communications synchronize the activities of connected PV Link substring optimizers and DC-coupled smart batteries with the inverter for resilience, self supply and arbitrage applications. The Pika Energy Island is a platform designed from the ground up. Hardware and software work together to deliver more power throughput, more energy capacity and more application flexibility than any other system on the market. Pika Islanding Inverters are able to deliver up to 50A of backup power to protected loads during power outages and control up to 68.4 kWh of Li-ion smart battery storage capacity.

Install advice: We expect to see our relationship to energy and the grid go through unprecedented change over the next decade. Anybody buying solar today will likely want a battery before too long, so plan in advance. With a Pika system that just means that you should leave some wall space clear near the inverter.

Monitoring: Every system ships with REview, a free system monitoring platform.


Full spec document

SMA | DC coupled storage solution

Can offer significant operating cost and efficiency advantages over AC coupled systems


SMA’s DC coupled storage solution is built for new PV plants, and can be used to retrofit existing plants for operators who want the benefits of solar-plus-storage. The solution consists of SMA’s Sunny Central EV-US inverters with a DC coupling ready option and up to six 500 kW DC-DC Converters.

Install advice: SMA’s Application Engineering team can help determine the appropriate battery size and number of DC-DC converters for a particular array in a specific location.

Monitoring: SMA’s Sunny Centrals have many options for connecting to a PV plant SCADA system via copper or fiber connections through an embedded communications device or additional managed switch.


Full spec document

Sol-Ark | 8K Hybrid Inverter

Built to survive EMP, solar flares, and cyber-attacks

sol ark hybrid

The DC Transformerless Sol-Ark 8K Hybrid Inverter is the most efficient battery inverter in the market, requiring 5-15% fewer solar panels, 5-20% less battery capacity and 25% lower cost electronics. Customers can expand as budgets allow. Built in 500 V MPPTs support five to 36 Solar panels (11 kW) DC coupled and also supports 7 KW AC coupling. Any type and size 48 V batteries can be used, even added later. Because it has 8 KW On Grid and 20 KW Off Grid peak power, home owners need only one. Install costs are reduced with a user wiring area and intuitive color touchscreen display. Sol-Ark 8K has many automatic modes: On Grid, Off Grid, Grid Tie/Sell, Home zero export, Battery Time of Use, Smart Load Time of Use, Peak Shaving, and auto gen start.

Install advice: Batteries can be an expensive investment. We are battery agnostic, but ask us for recommendations or use our online tools for sizing to a client’s needs. In 5+ years of business, we have never had a customer return because affordability and satisfaction are top priority to us.

Monitoring: In addition to the systems GUI graphical screens, free monitoring is offered on Android, Apple, and via web browser to understand and track solar generation, consumption, battery state of charge, and grid usage in 5-minute increments.


Full spec document

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Commercial & Industrial solar inverters

CPS America | 50- and 60-kW 1,000 Vdc string inverters

Remote service diagnostics and remote firmware updates

CPS 50 60 kw

The 50- and 60-kW (55 and 66k VA) medium power CPS three phase string inverters are designed for ground mount, large rooftop and carport applications, specifically for the North American environment and grid. High efficiency at 98.8% peak and 98.5% CEC, wide operating voltages, broad temperature ranges and a NEMA Type 4X enclosure enable this inverter platform to operate at high performance across many applications. The CPS 50/60-kW products ship with either the standard wire-box or the H4 style wire-box, each fully integrated and separable with touch safe fusing, monitoring and AC and DC disconnect switches. Smart-Grid Rule 21 & UL1741SA Certified, plus capable of 0-90° mounting orientation (vertical, angled, or lay flat).

Install advice: Integrate the Flex Gateway in the DAS enclosure to simplify commissioning and streamline service operations for the life of the system (one card per 70 inverters).

Monitoring: All CPS inverters, 3 phase or 1 phase, ship standard with Modbus RS485 communications. Our communication equipment uses industry standard Modbus protocol. The CPS Flex Gateway is a data communications and controls solution for the CPS inverter line. The gateway acts as a Modbus master data logger and gateway solution for communications and controlling commercial and utility scale inverter applications. This enables three parallel outbound communications options:

(1) Local pass-through Modbus data to 3rd party solutions,
(2) Ethernet based communications to CPS Service for remote diagnostics and updates,
(3) and a programmable Ethernet XML SunSpec Data Exchange connection for customers who want to manage their data directly.


Full spec document

Fronius | SnapINverter: Symo

Integrated SunSpec PLC transmitter for module level shutdown and field-serviceability

Fronius symo

The three-phase inverter line Fronius Symo features 10 models ranging from 10 kW to 24 kW, with the 208 V rated versions going up to 15 kW. The new Advanced versions combine the benefits of the Fronius Symo with additional value for states with Module Level Shutdown requirements, including integrated PLC transmitter for SunSpec Rapid Shutdown communication standard, compliance with NEC pre-2014, 2014 and 2017, zero tilt mounting, light weight and field serviceability. The Fronius SnapINverter line offers integrated Wi-Fi and SunSpec Modbus interfaces, NEMA 4X rating, wide voltage windows, multiple MPP trackers and easy installation in 15 minutes or less.

Install advice: Few tools are needed to complete a Fronius inverter installation, but the most important tool in our opinion is a torque screwdriver. Using this tool and paying attention to the provided torque specifications of the inverter will always ensure a safe and optimal installation.

Monitoring: Free lifetime monitoring comes standard with Fronius and Solar.Web. In it, you can check the performance of a system in addition to performing remote updates.


Full spec document

Outback Power | ProHarvest XL 480 VAC

A compact form factor ideal for rooftop and carport installations because it can be mounted out of sight

The ProHarvest XL might be the most power dense inverter available today. This new 10 kW version is Rule-21 compliant and weighs just over 30 pounds. The waterproof NEMA6 enclosure and fanless convection cooling at up to 65 °C ambient temperatures allow it to be mounted in any orientation under the array, on the wall, or attached to a carport purlin. The compact size and integrated connectors eliminate the need for DC combiners and associated hardware, which reduces labor and BOS costs. With dual MPPT inputs and a 200 to 850 VDC range, the PHXL480-10k can be used in 600 VDC or 1,000 VDC nominal installations, reducing SKUs and simplifying design as well as installation. AC output is configured in a 480 VAC wye configuration, uniquely suitable for many commercial projects.

Install advice: The ProHarvest series inverters allow for modular and flexible building blocks that can be deployed in almost any size of project.

Monitoring: The ProHarvest Communications Gateway adds monitoring and control communication with local inverters over the power line. Once connected, it will log data and store it on an internal memory card. Information may be accessed through the touch screen, or over an Ethernet network. Power line communications (PLC) means there is no need to run separate wires.


Full spec document

SMA | Commercial: Sunny Tripower CORE1

Enhanced safety features and 2017 NEC compliance via the new SunSpec PLC signal


The Sunny Tripower CORE1 inverter has been upgraded to new power classes. In addition to the 50 kW CORE1 model, a new higher power 62.5 kW model is available for large projects utilizing higher efficiency modules, and a 33-kW model is now available for projects with smaller or highly segmented arrays as well as 600 V repowering projects. The new CORE1 series will include advanced smart inverter capabilities to fulfill utility grid support interconnection requirements, as well as SMA’s next-generation DC AFCI technology for compliance to the new UL 1699B standard for arc-fault protection.

Install advice: String monitoring is a CORE1 feature that allows similarly strung inputs of the inverter to be benchmarked against each other, allowing for automated warnings if production of an input drops significantly. It’s a built-in O&M watchdog for the six inputs.

Monitoring: The SMA Data Manager M unlocks the updated Sunny Portal, powered by ennexOS. This updated portal allows for easy historical graphing of all data in the Analysis Pro section and provides improved fleet management. The classic Sunny Portal is available for internet connected CORE1 inverters, and either portal allows for signing up for SMA’s free Smart Connected.


Full spec document

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Utility-scale solar inverters

CPS America | 100- and 125-kW, 1500 Vdc String Inverters

No DC combiner box needed. A full featured 20 string input wirebox is integrated (and separable)

CPS 100 and 120

The 100- and 125-kW (111 and 132 kVA) medium power CPS three phase string inverters are designed for ground mount and carport applications at 1,500 Vdc, specifically for the North American environment and grid. High efficiency at 99.1% peak and 98.5% CEC, wide operating voltages, broad temperature ranges and a NEMA Type 4X enclosure enable this inverter platform to operate at high performance across many applications. The CPS 100/125 kW inverters ship with either the standard or “centralized” wire-box. The standard wire-box includes touch safe fusing, surge protection, AC and DC disconnect switches. The new centralized wire-box is designed for sites benefitting from DC combining near the array and locating the inverters closer to the point of interconnection. Both wire-box versions employ the CPS separable, “quick connect” wire-box design saving time installing and servicing the product.

Install advice: Install the Flex Gateway in the DAS box before commissioning the inverters in order to save time by commissioning the site at once, rather than each individual inverter.

Monitoring: The CPS Flex Gateway – normally one communications card per site – for remote service and product updates (to save service cost, increase diagnosis speed and uptime).


Full spec document

KACO | blueplanet 125 TL3

Silicon carbide semiconductors for a higher switching frequency, less conduction losses and a lightweight device

The blueplanet 125 TL3 is a string inverter for decentralized, large-scale solar power plants. It is KACO new energy’s first inverter designed for 1,500 volt modules. It is also the first inverter to consistently incorporate silicon carbide (SiC) semiconductors, which means the blueplanet 125 TL3 weighs less than 80 kilograms at a rated output of 125 kVA. This allows for a high power density, especially since the inverter allows for an oversizing of its AC power by 1.5 times while providing a reactive power reserve. The efficiency of 99.2 percent and the wide MPP range of 875 to 1,300 volts underline this high performance. There are a host of optional features available to adapt the inverter to one’s requirements: PID set, surge protection for AC connections and the communication interfaces, XL version with DC switch, WiFi. A standard feature is the protection against corrosion by salty air near the sea, which makes it possible to reduce the minimum distance to the coast from 2,000 meters to 500 meters.

Install advice: Use Ethernet communication for safety reasons. With the blueplanet 125 TL3, you’ll still be able to commission up to 100 inverters simultaneously. An Installation Wizard guides you through the configuration process. Later on, monitoring and maintenance can also be achieved remotely.

Monitoring: Monitoring data can be accessed via the integrated webserver, preferably using Ethernet or WiFi, or your chosen monitoring portal.


Full spec document

Sungrow | SG3150U-MV

Containerized design and pre-defined lifting points make it easy and quick to set

sungrow 2500U_SG3150UThis allows installers to use bigger block sizes and eventually reduce costs. The MPPT window for this product is 915 Vdc-1300 Vdc, which allows it to be used on almost all the PV modules manufacturers and technologies available in the market today. It is NEC 2017 compliant with insulation monitoring and ground fault monitoring functions. It can also be used to produce reactive power at night to support the grid. This inverter is coupled with a medium voltage transformer on the LV side which then steps up the voltage from low voltage to medium voltage. All the monitoring sensors/gauges of the transformer are accessible from outside which allows ease operation. The transformer also comes standard with FR3 oil, which is environmentally friendly. Like Sungrow’s previous central inverter, this inverter also has the modular feature to provides higher availability. The inverter has grid support features likes LVRT, HVRT, FRT, etc., and is compliant with UL and other regional standards. It has a peak efficiency of 98.8% and CEC efficiency of 98.5%.

Install advice: Every inverter comes with a maintenance schedule, and SG3150U has the minimum required maintenance schedule. It is advised to follow the specific installation and maintenance schedules as outlined in the product’s user manual.

Monitoring: The inverter has a Smart Control Unit (SCU), which collects data from the internal power electronic components and it also collects data from the transformer sensors. These transformer sensors are pre-wired from factory which eliminates the need of running more wires from transformer to customer Data Acquisition System (DAS).


Full spec document

Ginlong Solis | Solis 1,500 V 125 kW string inverter

All DC array connectors integrated into the enclosure for fast wiring and commissioning

Ginlong Solar inverters

The first thing an installer notices is how compact and lightweight the NEMA 4X 125 kW Solis 3-phase 1500V inverter is. The inverter is enclosed in a new, thin rectangular case that can be rack-stacked to MW levels. The new 3-phase product features intelligent redundant cooling for maximum performance in hot climates. A two-way communicating inverter (MODBUS / SunSpec), the Solis 125 kW can be remote controlled using SunSpec complaint hardware. This new inverter encourages installers to avoid installing combiner boxes and instead bring all strings back to the inverter and connect directly to the pre-installed MC4 bulkhead connectors. Inside the wiring box of the Solis 125KW, the installer will find 20 integrated fuse holders, load-rated AC/DC disconnect switches and integrated Class II overvoltage protection.

Install advice: Take your time during commissioning. The Solis inverters are particularly easy to commission so there is extra time for the installer to check all electrical connections and make sure that all the settings are correct in the internal menus. This extra few minutes at commissioning time will save time, money and headaches in the future.


Full spec document

SMA | Sunny Highpower PEAK3

Maximizes the benefits of distributed PV plant design


SMA’s PEAK3 inverter fulfills the need for flexibility, simplicity and performance in large-scale ground mount solar projects. The 1,500 VDC solution offers developers a cost-effective, modular building block that provides scalability while reducing balance-of-system and installation costs. Array combiners send one long pair of high-voltage DC conductors to each PEAK3 in the inverter station, with short AC runs to a collection panel and transformer, minimizing energy losses. Centralizing the inverters reduces communications cabling and inverter O&M time and effort. It is available in two models: 125 kW/480 VAC and 150 kW/600 VAC.

Install advice: Both AC and DC terminals are approved for copper or aluminum conductors, and no neutral is run to the PEAK3.

Monitoring: Sunny Highpower PEAK3 inverters are eligible for the SMA Smart Connected service, which offers proactive monitoring and O&M support that reduces plant servicing time and costs while maximizing system uptime, energy yield and ROI. Plant communications with the inverter are supported by the SMA Data Manager powered by ennexOS, SMA’s cross-sector energy management platform, providing an optimized interface for plant commissioning as well as intelligent monitoring and controls required in large-scale PV systems.


Full spec document

Yaskawa Solectria Solar |  SOLECTRIA XGI 1500

Access every inverter at once from a single location


yaskawa solectria xgi

Yaskawa Solectria Solar’s SOLECTRIA XGI 1500 inverters are powerful 1500V string inverters, with models rated at 125, 150 and 166 kW that boast a 99% peak efficiency rating. The SOLECTRIA XGI 1500 inverters use standardized communication protocols to ease connection to any network. This allows system owners to access all inverters on site from a single location using a secured WiFi and provides convenience for remote diagnostics and firmware upgrades. This new level of capability will lower system costs and improve the efficiency of operations.

Install Advice: Yaskawa Solectria Solar provides two lines of 1500V string combiners to accompany the XGI 1500 inverter. The 1500V Attachable Combiner is designed to mate with the XGI 1500 inverter, for distributed PV systems where the combiner and inverter are located together. For a centralized system configuration, we provide the 1500V Remote Combiner, for use when multiple XGI 1500 inverters are located in a central area and the combiners are spread throughout the PV array.


Full spec document

roof top reportDownload the new Residential Rooftop Report to heat up your solar sales

The Residential Rooftop Report for the first quarter of 2019 is now available for download. The theme is “Heating Up Sales,” and we’ve teamed up with report sponsor Aurora Solar to examine ways for residential solar installation companies to lower customer acquisition costs, close more leads and overall run a more streamlined, efficient local solar business. Just fill out the form below to access your free report.

— Solar Builder magazine

Riding the Wave: How Morningstar designed its software-first solar inverter for the lithium battery age

Morningstar Multiwave

Solar inverters have improved so much over the years that they are all starting to seem comparable in power and performance these days, but a new entry hitting the market from Morningstar stands out because it wasn’t being built for “these days.”

For starters, Morningstar isn’t a solar inverter company. It is an employee-owned business that has specialized in passively cooled charge controllers for 25 years. When it finally decided to develop its own solar inverter, the team started with a different goal in mind: Build the ultimate off-grid solar inverter for the lithium battery storage era. The tangible result, the 4-kW Multiwave solar+storage inverter, will be ready to ship this summer.

The Multiwave is best suited for markets where there is no grid or sell back is discouraged or not incentivized and operates in one of three ways: off-grid solar with generator backup (its primary segment right now); solar priority with grid support (a.k.a. self-consumption operation); and backup and uninterrupted power supply (UPS). Let’s look into how it works.

High(brid) frequency

At a base level, what makes Multiwave ideal for lithium batteries is (surprise) its charging capabilities. What goes into the battery is what comes out, with nary a conversion loss. To hit that level of efficiency, the inverter needed to use high-frequency topology.

“We came at this analytically: How can we design the next gen inverters for the post-lead-acid age?” says Mark Cerasuolo, marketing director for Morningstar. “We looked at where wanted to go and realized high frequency was the way to get there.”

Solar inverters are usually low frequency because it is a great way to generate grid-quality electricity while providing adequate protection for sensitive internal circuitry. This is all due to using/needing large transformers. High-frequency topology on the other hand can achieve switching at much faster rates and remove the need for large transformers and magnetics, but for years the componentry just wasn’t reliable enough to protect sensitivity circuitry.

Morningstar says they were able to smoosh together the advantages of high and low frequency by choosing hardware components for their performance instead of economics (over-specing in some cases), by relying on their thermal engineering expertise and by building it around the platform’s software capabilities.

The cool factor

OK, so I lied earlier, Morningstar built a solar inverter previously. They were involved in a big rural electrification project in Brazil that called for 20,000 300-W solar inverters that all had to be quiet, sealed and tamper proof. This led to the development of the SureSine.

“It will keep its cool all day at full tilt and surge up to 600 watts,” Cerasulo says. “They were even designed to take a dead short. You can’t hurt them. We cut our teeth on that.”

The Multiwave borrows from the SureSine template, mainly its quiet ruggedness and power. Like every product in the Morningstar lineup, the Multiwave doesn’t need a cooling fan, which is a common point of failure for chargers and inverters. They are also parasitic, noisey and capable of sucking in debris. They can burn out and are often warrantied for fewer years than the rest of the inverter. Morningstar prides itself on its thermal engineering, and Cerasuolo says the Multiwave is the only inverter in its power class that is passively cooled.

Software-driven results

As solar system installations increase, more PV systems will be installed by less skilled people and will require more of a focus on ongoing customer service and serviceability. This is why Morningstar spent more time on the software and interface than is typical.

“We used a bit of reverse thinking,” Cerasulo says. “The majority of inverters are hardware-focused first with the control software adapted to that. In this case, we wanted a solution that was more software driven and then a hardware platform that makes it possible.”

Morningstar Multiwave

With no transformer or cooling fans and fewer magnetics, the Multiwave is less cramped on the inside, making O&M simple.

The added design complexity on their end leaves less complexity on the installer and user’s end. Plus, with no transformer, no cooling fans, fewer magnetics and a software-first design, the Multiwave is lightweight and less cramped on the inside, making O&M (stuff like switching out the control board) simple for people with regular human hands. To me, this simplicity is another “future-proof” element of the Multiwave. Some examples:

  • It comes pre-programmed
  • One person can lift it and put it on a wall.
  • Much of the main circuitry is in one large board. So if there is a failure, you can swap it out pretty easily.
  • It is expandable. A built-in DIN “Ready Rail” allows you to add on and sync up generator control, system monitoring alert capabilities and battery management systems as simply as inserting a USB drive in a laptop.
  • To help achieve its No. 1 design goal — building it for the lithium battery era — the company can also provide specific programming instructions for any battery submitted to its lithium battery Partner Program.

Energy Storage Partner Program explained

Lithium batteries, specifically the safer lithium-iron phosphate (LiFePo) types, have a lot of potential, but they are higher priced than lead-acid and require different usage strategies and settings. The Energy Storage Partner program is purpose-built to address these nuances.

“It’s not as easy as just dropping this stuff in, so we said, well, let’s make it as easy as just dropping this stuff in,” Cerasuolo says.

On the product side, the MultiWave inverter/charger and selected Morningstar charge controllers have a lithium “foldback” feature. Lithium batteries can be damaged when charged under cold conditions. So, if it drops below freezing, the system will cut back on charging and even turn it off.

As for battery specific set points, that’s where the Energy Storage Partner Program comes in.

“Increasingly, we have installers asking for complete instructions on how to set them up with certain lithium batteries,” Cerasuolo notes. “So, for batteries in our Partner Program, we make sure they’re compatible and then we come up with the guide to use that battery with our product. Basically, what we’ve done is demonstrate our compatibility with the leading brands of advanced battery chemistries (mostly LiFePO4) to provide new and existing customers peace of mind that Morningstar products are able to adapt to the requirements of new battery technologies.”

“Through direct cooperation with each manufacturer, we have derived the appropriate setting values required for successful integration with each compatible Morningstar product,” says Jacob Sherry, applications engineer for Morningstar. “These settings correspond with industry-standard terminology and conventional charging algorithms found in battery-based power electronics.”

For example, many of the critical settings detailed in each document pertain to adaptation of the standard multi-stage charging profile used to charge lead-acid and other battery chemistries. Therefore, it is required that each brand provide specific recommendations for absorption voltage, absorption time and float voltage (if needed). Battery High Voltage Disconnect (HVD) and Load Low Voltage Disconnect (LVD) are also important settings to consider, since many controllers can be damaged due to a battery overvoltage disconnect during charging. Similarly, many lithium batteries may require manual site intervention at uncontrolled low Depth of Discharge (DoD).

“All of these values can vary quite significantly between manufacturers, depending on their specific cell characteristics and the tolerances of their particular Battery Management System,” Sherry says. “Having these settings and information properly documented provides a wonderful convenience for our customers who may be interested in exploring the benefits of newer battery technologies, without losing the quality and reliability of their favorite charging solution.”

The Multiwave isn’t shipping yet, but you can check it out at the NABCEP Continuing Education Conference March 26-27. If you’re interested in adding lithium batteries to a new or existing system, check out Morningstar’s Energy Partner Program here.

— Solar Builder magazine

Koolbridge Solar gets UL approval for Renewable Energy Smart Load Center


Koolbridge Solar‘s renewable energy product, the SMART LOAD CENTER (SLC), has been awarded UL (Underwriters Laboratories) approval. UL is the world leader in advancing safety sciences and achieving the UL 67 and UL 60730-1 listing marks a breakthrough for the young North Carolina company.

The SMART LOAD CENTER provides data collection, reporting, monitoring, and engagement by integrating today’s state of the art technology into a traditional breaker box format resulting in a solution that seamlessly provides a residential distributed energy software management solution for both solar and grid-based electricity throughout the home on a branch circuit-by-circuit basis.
Even when solar and grid power are both available, the intelligence built into the SLC gives preference for using someone’s own, free solar power by switching as many breaker circuits to solar as it can at that time.

Once full production begins, the SMART LOAD CENTER will be made available initially through U.S. solar installers, dealers and resellers.

Smart Load Features

  • Preset User Priorities – prioritizing loads to match available solar power to home power demand
  • Minimize reliance on the electrical grid
  • Maximizes use of your own free solar power
  • Communicates with PCs or laptops
  • Displays current and historical power usage by time, per circuit and per energy source
  • Time-of-day dependent operations may be programmed
  • Peak Demand Control
  • Real-time appliance power usage
  • Battery technology agnostic
  • Inverter agnostic (inverter must be a load-supporting inverter and inverter and battery must be compatible)
  • Integrated tracking of energy utilization independently for each branch circuit
  • Coordination of total load on inverter and grid to avoid falling foul of time-of-use tariffs
  • Dynamically adjusts loads to match the power available
  • Fits flush between 16” spaced wall studs in standard US wood frame construction

— Solar Builder magazine