What the product is and who it suits

Fox ESS R110 is a 110kW three-phase commercial string inverter from the Fox R Series. It is intended for large grid-connected solar PV installations where the array size, building scale and string layout are beyond the natural scope of smaller commercial products. Typical sites include factories, distribution units, large agricultural facilities, business parks, schools and major warehouse roofs where there may be several distinct array groups feeding one inverter.

The reason to choose the R110 over smaller options is not just higher output. Fox lists the unit with ten independent MPPTs and two strings per MPPT, giving a total of twenty string inputs. That changes the design options materially on large roofs because it allows more roof sections to be separated properly. On a site with many roof faces, changes in pitch or interruptions from plant and parapets, that string-level flexibility can be as valuable as the 110kW power rating itself.

Within the Fox range, the R110 sits above the R75. It is the better fit where the project needs more output and more MPPT count from a single inverter. On the LAMPS site it also belongs naturally within the wider three-phase solar inverter category and the broader Fox ESS product family.

Key features and practical benefits

Fox lists the R110 with 1100V maximum input voltage, 250V start-up voltage, 200 to 1000V MPPT operating range and 550 to 850V full-load MPPT range. Maximum input current is 26A for each MPPT and maximum short-circuit current is 40A for each MPPT. Maximum efficiency is listed as 98.6% and European efficiency as 98.2%.

Those figures support large commercial string design in a practical way. Ten independent MPPTs allow the inverter to manage many more separate string groups than a standard commercial product. That reduces the need to merge electrically different roof sections into the same tracker and gives designers better control over how the PV field is structured. For buildings with long roof lines, multiple blocks or several aspect changes, that is a major advantage.

The voltage and current figures matter as well. A broad 200 to 1000V MPPT operating window supports flexible string design, while the 26A current allowance per MPPT is important with modern higher-current modules. The 550 to 850V full-load range is also a useful design reference because it tells specifiers where the inverter is intended to deliver strong continuous performance.

• 110,000W rated AC output for large commercial PV systems
• Ten independent MPPTs with two strings per MPPT
• 200 to 1000V MPPT range and 1100V maximum DC input voltage
• 26A maximum input current and 40A maximum short-circuit current per MPPT
• 98.6% maximum efficiency and 98.2% European efficiency

Technical detail that matters in practice

Fox lists the R110 with 400V three-phase grid connection, a 320 to 460VAC grid voltage range, 45 to 55Hz or 55 to 65Hz grid frequency ranges, power factor adjustment from 0.8 leading to 0.8 lagging and total harmonic distortion below 3%. Maximum apparent power is listed as 121kVA and maximum output current as 175.3A. Those figures underline the fact that this is a serious commercial inverter intended for large-scale three-phase operation, not a stretched domestic format.

Connections are listed as MC4 on the DC side and OT terminal on the AC side. Physical dimensions are 975 × 630 × 360mm, with a listed weight of 90kg. That keeps the product within wall-mounted commercial inverter territory, but the size and cabling demands still place it firmly in the professional installation category.

Cooling is listed as smart air cooling. Fox also lists operating temperature from -30°C to 60°C, humidity from 0 to 100% without condensation and altitude up to 4000m. For large external commercial sites, those are meaningful practical figures rather than background data. They help explain why the R110 is suitable for open plant areas, external walls and other demanding service environments when installed correctly.

Installation, monitoring and control

The enclosure is rated IP66, which supports outdoor installation where project layout makes that the most practical option. On large roofs and commercial compounds, that can be a major advantage because the inverter can be placed closer to the PV field or distribution equipment. In a full system it will normally operate alongside suitable solar panels and other commercial balance-of-system hardware.

Fox lists a strong set of communication options, including RS485, USB, WiFi plus LAN and optional 4G. Monitoring is supported through LED indication, app visibility and wider communication interfaces. For installers, O&M teams and system owners, that means the R110 can be integrated into a monitoring regime where performance review and remote diagnosis matter across large assets.

Meter-linked and communication-based control functions are also relevant on projects with export management or wider building-energy oversight. That is why buyers specifying a system at this level often review associated optimisers and meters and control hardware as part of the same project rather than treating the inverter as an isolated component.

Protection, standards and warranty

Fox lists a substantial protection package for the R110, including a DC switch, DC reverse polarity protection, AC overcurrent protection, AC short-circuit protection, DC Type II surge protection, AC Type II surge protection, PID recovery, insulation monitoring and residual current monitoring. AFCI and PV string current monitoring are listed as optional. Those features matter because fault response, commissioning clarity and long-term reliability expectations are higher on large commercial systems.

Standards listed in the official documentation include IEC 62109, IEC 61727, IEC 62116, IEC 60068, IEC 61683, IEC 61000-6-3 and EN 50549. That provides a grounded technical basis for the product page and is more useful than generalised claims about performance or quality.

Warranty follows the current Fox UK and Ireland inverter policy. The standard term is sixty months from the date of installation, capped at sixty-five months from the date of manufacture, whichever comes first. Fox also states that R Series units can receive an additional sixty months where the product is registered within the stated timeframe and registered to Fox Cloud using a Fox datalogger for remote monitoring. On larger commercial sites, that registration step is worth managing properly because it affects the available cover.

Why this variant may be the better fit

The R110 is the better choice where a project needs a higher-output single inverter and a higher MPPT count than the R75 can offer. That may be because the roof area is larger, because there are more array zones to manage, or because site demand and project economics support a bigger inverter platform. The move from nine MPPTs on the R75 to ten on the R110 may sound modest, but on a complicated roof it can be enough to keep another section electrically separate rather than combining unlike strings.

That is the buying logic behind the model. It exists for sites where roof complexity and project scale are both high. Buyers who need slightly less capacity can compare it with the Fox ESS R75, while the R110 is the stronger choice for larger commercial arrays that still suit a string-inverter architecture.

Frequently asked questions

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