# Off-Grid Microgrid Customization off-grid microgrid engineering for sites without reliable mains for islands, mining sites, oilfields, pastoral regions and telecom bases. **Fig. 1｜**A typical island off-grid microgrid: rooftop and ground PV, wind turbines, containerised storage and a genset, all dispatched by one EMS — renewables carry the load and charge storage by day, storage and the genset take over at night or during prolonged bad weather. Off-grid microgrid customization · dependable power where there is no utility Off-grid customization: turning the genset back into a backup plant The hard part of an off-grid system is not generating power — it is surviving **the worst few days**: consecutive overcast weeks, storm season, a winter peak at a remote wellhead. We size against the worst month rather than the annual average, define sub-cycle transfer and load shedding by priority, and let the genset run only when it truly has to. Islands, mines, oilfields, farms and telecom sites each have a proven path with us. **8–72 h**Autonomy configurable per project **60%–90%**Diesel displacement typically achieved **below 10 ms**Uninterrupted transfer on internal-STS models **3–7 days**Usual renewable self-sufficiency design window 1. Where it fits Three numbers decide whether off-grid storage makes sense: annual consumption, landed diesel price and resupply interval. The more remote and expensive the logistics, the stronger the case. Islands and coastal villages Desalination, cold chain, guesthouses and community loads, with salt-mist corrosion and low storm-season irradiation to manage. Mining and construction camps Crushers and hoists create three- to sevenfold inrush; the camp load is strongly day/night, ideal for storage. Oilfields and pipeline nodes Pump jacks are cyclic impact loads; sites are scattered, unmanned and need remote supervision. Farms and ranches Irrigation and milking cluster in the morning and evening; land is available for ground-mount PV plus containerised storage. Telecom and repeater sites Small load, zero tolerance for outage; IP65 wall-mounted units with remote battery health management. Border posts and emergency supply Silent operation, low thermal signature and fast deployment, optionally supplemented by mobile storage units. 2. First fork: DC-coupled or AC-coupled This decision shapes the equipment list, the round-trip efficiency and every future expansion. DC coupling PV joins a DC bus before a single inversion. Solar only needs one DC/DC and one DC/AC stage, so round-trip losses are lower and gensets can stay stopped for long stretches. The trade-off is that the PV controller participates in system control and AC-side expansion is less flexible. Fit: high renewable share, genset purely standby Fit: PV and storage built together in one phase AC coupling Each subsystem stands on the same AC bus. You can start from a genset with modest storage and add PV capacity later. Several of our platforms support both coupling modes, so a mixed first phase can grow in either direction. Fit: staged build or an existing genset already on site Fit: sites where the load may grow substantially 3. Five things that decide success 01 Size to the worst month, not the annual mean Take the worst consecutive three to seven days of historic irradiation or wind as your floor, then derive how long storage must carry and how much the genset must cover. Systems sized on annual averages come out visibly too small. 02 Check inrush as a separate item Motor starting current reaches three to seven times rating. Either the PCS carries defined short-term overload or you add soft starters and variable-speed drives; otherwise the converter has to be sized for the peak and costs climb. 03 Write down the start/stop rules Start the genset at a low SOC threshold, stop it at an upper one, and enforce minimum run time and minimum loading to avoid short cycling and wet stacking. 04 Classify loads and practise shedding Split the load into critical, important and sheddable. When SOC bottoms out or a unit trips, the EMS sheds upwards from the bottom so communications, lighting and medical loads survive. 05 Do not compromise on environment Coastal sites need salt-mist protection and heavy-duty corrosion class; plateau sites need altitude derating; desert sites dust-proofing and thermal management; cold sites a heated and insulated battery enclosure. 4. Three lines for a first estimate Usable storage kWh = Paverage load × Tdark hours to cover ÷ (DOD × η); _plan one to three self-sufficiency days_ PV kWp = Edaily consumption ÷ (worst-month peak sun hours × system efficiency); _then check 1.2–1.6× PCS oversizing_ Genset kW ≥ max(base load ÷ 0.75, battery charge power + critical load) **Two classic mistakes** — sizing from annual yield only, which leaves you short in winter; and saving money on converter overload capability. Both surface during the first year of operation. 5. Configuration reference Typical configurations by site size (final values from simulation) Site typeDaily consumptionPCS powerStorage capacityPV array Telecom / repeater30–120 kWh10–30 kW60–200 kWh20–60 kWp Farm / ranch200–600 kWh50–125 kW300–800 kWh150–400 kWp Village / community1–3 MWh300 kW–1 MW2–6 MWh800 kWp–3 MWp Mining camp / oilfield5–20 MWh1–5 MW4–20 MWh3–12 MWp 6. A working equipment set Four platforms cover most off-grid designs: the main unit establishes the AC bus and performs transfer, MPPT harvests each string, DC/DC integrates different battery voltages, and the wall-mounted unit serves small outdoor sites. [SP375 / SP500HAG2 All-in-one hybrid inverter Integration PCS + MPPT + EMS + transfer + distribution Battery side 680–950 V, max 600/800 A PV input 120 kW × 3 / × 4 Enclosure IP54, plug-and-play View details →](/en/product/sp375-500hag2) [SP200HAPV / SP150HAPV PV MPPT controller (buck-boost) Rated power 200 kW / 150 kW MPPT range 200–900 V Peak efficiency 99.26% Mounting IP65 wall-mount View details →](/en/product/sp200-150hapv) [SP210HCDC Bidirectional DC/DC controller Rated power 210 kW Voltage range 200–950 V Peak efficiency 99.2% Feature Bidirectional buck-boost, parallelable View details →](/en/product/sp210hcdc) [SP135HAPSS Wall-mounted storage converter Protection IP65 Mounting Wall-mounted Input Dual AC input with ATS Feature Internal transfer plus genset hybrid operation View details →](/en/product/sp135hapss) 7. Delivery sequence Data collection Load list, daily curve, coordinates and climate data, existing genset model and fuel records. First sizing Two or three power/capacity options with capex and fuel saving compared. Simulation check Hour-by-hour SOC, curtailment, genset hours and autonomy verification. Engineering and quotation Single-line diagram, layout, earthing and surge protection, supply list and lead time. Build and FAT Cabinet manufacture, full integration test, load and transfer tests, burn-in. Commissioning and training Installation guidance, SAT retest, O&M training and spare parts handover. 8. Sites in service Island project: most diesel displaced, quiet nights 200 kW class site: replacing gensets for a community Off-grid areas: stable power for schools, clinics and homes Farm scenario: irrigation and processing loads covered 9. Frequently asked Can we drop the genset entirely? Technically yes, but covering the worst seven to ten consecutive days demands very large storage and PV. Most projects keep one genset as insurance and push its annual running hours down to a few hundred. Will cloud cover cause sudden blackouts? Not with SOC-linked genset start. The EMS starts the engine before SOC reaches the floor and sheds non-critical load first if the deficit persists. How is maintenance handled remotely? The system reports telemetry so cell imbalance, fan faults and similar issues surface early. We also hand over a wear-parts list and train local staff, keeping on-site interventions short. Can we keep our existing genset? Usually yes. We adapt its interface and control so it runs only inside its efficient loading band — which is exactly what a diesel-storage hybrid is for. Tell us where the site is and what it needs Send the daily load curve, longest acceptable outage and existing genset details — we return a configuration validated against your worst month. [Request an off-grid proposal](/en/contact)