Swapping the inverters on a commercial solar system means the worn units come out and new ones go in while the panels stay where they are. At Elsoms Seeds in Spalding we replaced the Power One/ABB inverters on a 177kW array fitted in 2013 with six Solis 25kW string inverters. The work took five days, added remote monitoring and kept the Feed-in Tariff generation meter separate from a new 100kW array.
Are Your Solar Inverters Due for Replacement?
- Inverter health assessment
- FiT-compliant upgrade solutions
- Modern monitoring & improved efficiency
Replacing Power One/ABB inverters on a 177kW array
Spectrum Energy Systems installed the original 177kWp solar PV system for Elsoms Seeds back in 2013. After more than a decade of service, the original Power One/ABB 27.5kW inverters had reached the end of their working life. That is common: inverters typically begin deteriorating after 7 to 8 years and rarely last beyond 10. Our guide to how long solar inverters last covers the detail.
As the original installers, with a relationship going back more than 12 years, we were asked to handle the replacement. It was not a simple swap. Alongside the ageing inverters, we had to tie the system in with a new 100kW array being installed in early 2025, while preserving the original system's Feed-in Tariff eligibility.
We designed the replacement around 6 Solis 25kW string inverters, chosen for their reliability and monitoring. The result is a modernised system with remote visibility of both arrays combined, something the 2013 technology could not provide. We have been installing solar since 2011 and are NICEIC approved (Reg. 3182878) and a RECC member (00080159).
A 12-Year Partnership
This Project Is Ideal If You Have:
A commercial solar system over 7 years old with original inverters
Feed-in Tariff eligibility you need to protect during upgrades
A desire for remote monitoring and real-time system visibility
Plans to expand your existing array with additional capacity
The challenge: new inverters, a new array and a Feed-in Tariff to protect
Swapping old inverters for new was the easy part. The hard part was integrating the replacement inverters with an entirely new 100kW array that Elsoms had commissioned us to install at the same time.
The original 177kW array benefits from Feed-in Tariff (FiT) payments, which provide income based on the energy generated. The new 100kW array does not qualify, because the scheme closed to new applicants from 1 April 2019 (Ofgem). That set a firm requirement: the new array's generation couldn't "go through" the existing array's generation meter, as this would falsely boost the kWh total and potentially breach FiT regulations. We explain the rules in our article on adding panels and keeping your Feed-in Tariff.
Elsoms also wanted remote visibility of both arrays combined, allowing them to monitor total site generation and consumption from anywhere with internet access. Doing that while keeping the metering separate made the design harder still.
On top of the electrical design, we had to route lengthy communication cables both externally and internally through a busy commercial warehouse, working around strict health and safety protocols and ongoing operations. The layout of the buildings called for some careful cable containment to keep the installation tidy.
The solution: six Solis 25kW inverters and an Export Power Manager
The replacement uses 6 Solis 25kW string inverters, chosen for their reliability on commercial sites and their monitoring. Our Solis inverter review sets out why we fit them.
Keeping the FiT compliant while monitoring both arrays together came down to the system architecture. We installed a Solis Export Power Manager (EPM) that allows both arrays to work together to reduce grid consumption, but keeps the generation metering separate. The new array's output doesn't affect the original system's recorded generation figures.
To provide the site-wide visibility Elsoms required, we designed a new metering arrangement connected to an externally located sub-station that supplies power to the entire site. This captures true load and export data across both arrays, feeding into the Solis monitoring platform for real-time remote access.
The Solis daisy chain cable configuration links all six inverters, so their data arrives through a single monitoring interface. The original 2013 system had no remote monitoring at all. Elsoms can now track performance, spot faults and verify generation from anywhere with internet access.
Technical Specifications
Need to Protect Your FiT During an Upgrade?
We carry out inverter replacements and system expansions that preserve your Feed-in Tariff eligibility.
How the inverter swap ran: five days on site
The inverter replacement was completed in five days, coordinated around Elsoms' operations. Working in an active industrial warehouse meant strict health and safety protocols throughout.
The installation involved mounting all six Solis 25kW inverters on the plant room wall, creating a clean, accessible lineup that allows for easy maintenance and monitoring. Each inverter was connected to its respective panel strings, with the daisy chain communication cable linking all units together.
One of the more challenging aspects was routing the communication and metering cables. These needed to travel from the inverter room to the external sub-station, passing through both internal warehouse spaces and external areas. We designed a containment route that kept the cables protected and the installation tidy, which is not easy on a working site.
The Solis EPM was configured to manage power flow between both the original FiT array and the new 100kW system, with the new metering equipment installed at the sub-station to capture accurate site-wide data. Final commissioning included thorough testing of all monitoring systems and verification that the FiT generation meter remained correctly isolated from the new array's output.
Throughout the process, our team maintained close communication with Elsoms' facilities management, coordinating access and working hours to minimise impact on their operations. Our commercial solar maintenance services keep systems like this performing for years to come.
The result: modern inverters, remote monitoring and the FiT intact
Elsoms Seeds now has modern inverters that should serve for another decade, in place of ageing Power One units that had reached the end of their working life.
Key Outcomes
The new Solis inverters provide substantially improved efficiency compared to the 12-year-old units they replaced. Modern inverters feature better Maximum Power Point Tracking (MPPT), lower conversion losses and better power management, all of which mean more usable energy from the same panels.
The biggest change is remote monitoring. Where the original system required on-site checks to verify performance, Elsoms can now monitor both their 177kW FiT array and their new 100kW system from anywhere with internet access. Real-time generation data, fault alerts, and historical performance records are all available through the Solis monitoring platform.
The EPM lets both arrays work together to offset site consumption while keeping the separation that FiT compliance requires. This was the hardest part of the project, and it works as designed.
For businesses with aging solar systems, our guide to smart solar investment explains how proactive maintenance and timely upgrades protect your returns over the system's lifetime.
How Old Are Your Solar Inverters?
If your inverters are approaching 7 to 10 years old, now is the time to plan for replacement, before an unexpected failure costs you generation.
A Partnership Built on Trust
Elsoms trust Spectrum implicitly. Our working relationship is very robust. They knew that we would complete an exceptional job and do exactly what we set out to achieve.Elsoms Seeds
Our relationship with Elsoms Seeds spans over 12 years, from the original 177kW installation in 2013 through to this comprehensive upgrade project. A client who comes back again and again is the best endorsement our work can have.
Forging strong working relationships that span many years is, as we see it, the best business of all. It's why we maintain detailed records of every system we install and why our commercial solar clients know they can rely on us for ongoing support throughout their system's lifetime.
Project Gallery
Common Questions About Inverter Replacement
"My inverters still seem to be working. Do I really need to replace them?"
Inverters often deteriorate gradually before failing completely. Reduced efficiency, more frequent faults, and declining generation can cost you money without obvious symptoms. A professional assessment can identify whether replacement now prevents costly downtime later.
"Will replacing inverters affect my Feed-in Tariff?"
No. Inverter replacement doesn't affect FiT eligibility. However, if you're also expanding your system, careful design is essential to keep generation metering separate. We've handled many FiT-compliant upgrades, including this complex dual-array integration. Full details of what's included are on our inverter replacement service page.
"Why Solis inverters rather than other brands?"
We chose Solis for Elsoms for their reliability on commercial sites, their monitoring and the manufacturer support behind them. We work with multiple inverter brands and recommend the best fit for each specific project.
"Can you work around our business operations?"
Yes. We completed this project in a busy industrial warehouse with strict health and safety protocols, coordinating access and timing to minimise disruption. We know that downtime costs money.
We support commercial systems across Lincolnshire. See our solar panel installers in Spalding page for local work, and our solar installation in Lincoln team covers every LN postcode.
Frequently Asked Questions
Most commercial inverter replacements take 3 to 5 days, depending on the number of inverters, system complexity and site access. At Elsoms Seeds we replaced six inverters and integrated a new 100kW array in five days. We prepare all the equipment before the switchover so the system is offline for as short a time as possible.
Yes. At Elsoms Seeds the original Power One/ABB inverters, fitted in 2013, were replaced with six Solis 25kW string inverters connected to the existing panel strings. The panels stayed where they were. The new inverters also brought remote monitoring, which the 2013 system did not have.
Replacing inverters does not affect Feed-in Tariff eligibility as long as the system capacity stays the same. If new panels are added at the same time, their generation must be kept off the FiT generation meter. At Elsoms Seeds we used a Solis Export Power Manager and separate metering to do exactly that.
Warning signs include generation falling compared with previous years, frequent error codes or faults, an inverter running hotter than usual, or complete failure. If your inverters are over 7 years old it is worth having them assessed, so a replacement can be planned at a time that suits you and not forced by a breakdown.
The Power One/ABB inverters were installed in 2013 and replaced in 2025, so they gave about 12 years of service. The solar panels they served are still in use. Panels outlast inverters, which is why most commercial solar systems need at least one inverter replacement during their lifetime.
Modern inverters are more efficient than those from 10 or more years ago, with better MPPT (Maximum Power Point Tracking) and lower conversion losses. They also offer remote monitoring that older inverters lack. At Elsoms Seeds, both the 177kW array and the new 100kW array can now be checked from anywhere with internet access.
Is Your Solar System Due for an Inverter Upgrade?
If your commercial inverters are approaching 7 to 10 years old, now is the time to plan ahead. Get an assessment and see how modern inverters can restore, and improve, your system's performance.
Learn More About Commercial Solar Maintenance
Regular maintenance and timely component upgrades protect the return on a commercial solar system. Our complete business solar guide covers everything from system sizing to ongoing maintenance.
Browse more examples of our commercial work in our solar installation case studies, or learn about our comprehensive solar panel maintenance and support services that keep systems performing at their best throughout their 25+ year lifespan.
