Short answer: workshops, warehouses and factories need a different solar design from homes because motors, compressors, welders, pumps, machinery and three-phase loads can create large starting currents, uneven phase loading and short-duration peaks. Commercial design must separate what solar should offset from what batteries should actually back up.
Start with a load study, not the monthly bill
A factory can have the same monthly kWh as another site but a completely different maximum demand. Record the largest simultaneous loads, motor start events, operating shifts and phase currents. Where possible, use interval or power-logging data.
Three-phase questions to answer
- Is the supply three-phase four-wire or another arrangement?
- Are major loads single-phase or three-phase?
- How balanced are the phases?
- What machinery has high starting current?
- Which loads need UPS-like continuity and which can stop safely?
- Can heavy loads be scheduled into solar hours?
Why motors change inverter sizing
A motor may draw several times its normal current during startup. Inverters have different surge ratings and motor-start behaviour. Simply adding nameplate running watts may underestimate the required power capability.
When batteries should not carry everything
It can be uneconomic to back up every high-power process for hours. A more practical design may keep controls, IT, lighting, security and selected production lines alive while a generator or grid handles the largest machinery. Solar can still offset daytime energy used by heavy equipment.
Parallel inverters and larger systems
Some inverter platforms permit parallel operation, but only under specific manufacturer rules. Victron's documentation, for example, requires identical parallel units, equal DC cable length/cross-section and configuration as one system. These principles show why commercial parallel systems should be engineered rather than assembled ad hoc. See Victron's parallel installation guidance.
Protection and distribution
Commercial sites can require larger switchgear, surge protection, isolators, distribution-board modifications, fire/safety controls and metering. The final design may also need professional engineering and distributor approval depending on capacity and grid connection.
Whitehouse commercial project approach
We can develop tailored requirements for workshops, warehouses and factories and source around the project rather than limiting the design to the small set of residential products listed online. This is especially important for three-phase systems, larger battery banks and specialised protection.
Factory quote checklist
| Data | Why it matters |
|---|---|
| Three-phase supply details | Defines architecture |
| Maximum demand / interval data | Shows peaks |
| Motor and compressor ratings | Surge sizing |
| Operating shifts | Energy timing |
| Critical production loads | Backup priority |
| Roof/yard space | PV potential |
| Generator details | Hybrid strategy |
| Tariff structure | Savings model |
| Expansion plans | Future capacity |
Phase balance can make or break a three-phase design
A three-phase site may have large single-phase loads unevenly distributed across phases. A total building load of 15kW does not mean each phase carries 5kW. Measure the actual phase currents and understand which equipment is connected where before choosing the inverter architecture.
Power quality and control loads
Some machinery depends on PLCs, contactors, variable-speed drives or sensitive controls even when the mechanical load itself is too large to back up. Keeping control circuits, network equipment and safety systems alive can allow faster recovery or controlled shutdown without sizing batteries for the entire factory.
Commercial solar is often two projects in one
The first project is energy offset: use PV to reduce purchased daytime kWh. The second is resilience: decide which loads must remain powered during supply failure. Separating these objectives can produce a more cost-effective design than trying to put every machine on batteries.
Whitehouse currently lists scalable residential/light-commercial platforms such as the Deye 8kW Hybrid Inverter and Luxpower SNA6000 Hybrid Inverter + CT. A workshop or factory may need substantially larger or three-phase equipment sourced specifically for the project.
FAQ
Can a factory go completely off-grid?
Technically possible for some sites, but generation, storage, redundancy and worst-case weather requirements can make a grid-connected hybrid or generator-supported design more practical.
Can solar reduce a factory bill without batteries?
Yes. If loads are concentrated in daylight, PV can offset energy directly. Batteries add resilience and time-shifting but are not mandatory for every savings case.
Can Whitehouse arrange larger systems outside the online catalogue?
Yes. Commercial projects can be sourced and quoted to the specific site requirement.
Get a tailored Whitehouse solar or backup-power quote
Whitehouse Lighting & Electrical can help you build a solution around your actual loads, budget, property and expansion plans. We do not rely only on the products shown online; where a project needs a different inverter size, battery bank, protection arrangement or commercial configuration, we can source around the brief.
We arrange solar and backup-power solutions for homes and businesses across South Africa, including Secunda, Ermelo, Mpumalanga, Mbombela/Nelspruit, Johannesburg, the East Rand, Pretoria, North West and Bloemfontein. Panels, batteries and other bulky equipment may need a dedicated delivery quotation depending on route and handling.
Important: this guide is for planning and buying decisions. Cable sizes, protection ratings, earthing, DB alterations, PV strings and final system settings must be confirmed for the actual installation by appropriately qualified persons and the relevant manufacturer documentation.
