How accurate is the mounting support spacing output?

The spacing is a preliminary estimate rounded to 50 mm and capped at 1600 mm. It uses simplified beam and clamp uplift capacity assumptions from the selected wind standard (AS/NZS 1170.2, ASCE 7-22, or EN 1991-1-4). Final certified spacing must be confirmed by the mounting manufacturer's span table or a licensed structural engineer using project-specific load inputs.

What markets and wind standards does this BOS calculator support?

The calculator supports Australia/NZ (AS/NZS 1170.2 wind regions A–D), USA/Canada (ASCE 7-22 Vult with exposure categories B/C/D), Europe and global markets (EN 1991-1-4 with 13 country vb values including Germany, UK, France, Netherlands, Spain, Italy, Poland, Sweden, South Africa, UAE, Philippines, India, Japan), South-East Asia and Middle East/Africa via the EU standard with regional defaults, and a manual input for any other standard.

What does the battery storage sizing tab calculate?

The storage tab calculates gross battery capacity in kWh and Ah for LFP, NMC, and VRLA chemistries. Inputs are daily load kWh, autonomy days, battery system voltage, and minimum temperature zone. The calculator applies depth-of-discharge (LFP 90%, NMC 85%, VRLA 50%), a 90% system delivery efficiency (battery discharge + inverter losses), and per-chemistry temperature derating (LFP: 0.75–1.0, NMC: 0.65–1.0, VRLA: 0.50–1.0).

How do I send the BOM to OmniSol for a factory quote?

Use the "Send BOM on WhatsApp" button on the Full BOM & Quote tab to send a project summary directly to OmniSol's sales team. Alternatively, use "Copy Full BOM" and paste the complete SKU list into an email or spreadsheet. OmniSol will map each SKU to available product families, confirm variants, and return a factory-direct quotation with lead time and consolidated freight options.

How is the DC SPD Ucpv voltage rating calculated?

The SPD Ucpv is calculated using the open-circuit voltage at the minimum site temperature, not at STC. Voc increases as temperature drops — typically by about 0.28%/°C for crystalline silicon modules. The formula is: Voc_max = Voc_STC × (1 + tempCoeff × (T_min − 25)). For example, at −10°C with a −0.28%/°C coefficient, Voc is approximately 9.8% higher than STC. The SPD Ucpv is then selected as the next standard value above 1.2 × Voc_max × panels per string.

What is the correct string fuse sizing method?

Per IEC 60364-7-712, the minimum string fuse rating is 1.25 × Isc of the string. The selected fuse must also not exceed the module's maximum series fuse rating specified on the module datasheet. A common mistake is applying a 1.25² (1.56×) factor, which is incorrect and results in oversized fuses that provide inadequate protection. Enter your module's max series fuse in the Protection tab to check compatibility.

Can I enter actual module datasheet values instead of auto-estimated ones?

Yes. In the Cable & Connectors tab, enter actual Voc and Isc from your module datasheet. Setting either field to 0 reverts to the auto-estimate from wattage. Providing actual values improves cable sizing, combiner fuse selection, SPD Ucpv calculation, and DC isolator rating — particularly important for high-efficiency or bifacial modules where the datasheet values may differ significantly from the wattage-based estimate.

What does "Market Restriction" mean in the BOM?

Items marked "Market Restriction" (shown in orange) are products that OmniSol supplies but may require market-specific certification variants. For example, US projects require UL-listed protection components (UL 1077, UL 508) rather than IEC-certified ones. OmniSol can source or recommend UL-listed alternatives — confirm the specific variant required at RFQ stage.

How is the DC isolator rating calculated when there are multiple combiner boxes?

Each combiner box output has its own DC isolator, so the isolator is sized for the strings routed through that particular box, not the total array current. For example, with 16 strings split across 2 combiner boxes, each isolator is rated for 8 strings × Isc × 1.25 — not 16 strings × Isc × 1.25. This prevents significant oversizing and avoids false "isolator range exceeded" warnings. The BOM quantity reflects one isolator per combiner box (or one for direct-to-inverter layouts).

What if my RFQ only has brand names or incomplete specifications?

Use the Distributor RFQ mode and add each line with whatever information you have — brand name, model family, approximate spec, or just a product category. OmniSol will attempt to match each line to an available SKU and flag any items that need further technical clarification. Lines that cannot be matched immediately are marked "Not Yet Sourced" and the procurement team will follow up with sourcing options.

What does "Budget FOB" or "Preliminary FOB" mean on a solar hardware quote?

Budget FOB is an indicative ex-factory price at the time of inquiry. It is not a firm offer. Final pricing depends on confirmed order quantity, production schedule and currency at the time of purchase order placement. OmniSol reconfirms all prices before issuing a formal Proforma Invoice (PI). Lines marked "Preliminary Budgetary Subtotal" in the RFQ tool should be treated as planning estimates only.

Solar BOS Calculator

Solar BOS Calculator & Preliminary BOM Builder

Estimate BOS requirements from your array layout, configure a hybrid solar kit, or organize an existing procurement list for preliminary sourcing and quotation.

Preliminary estimation tool — not a certified engineering design. Confirm all sizing with project datasheet, manufacturer span tables, and a licensed local professional before ordering.

How would you like to start?

Already have an incomplete procurement list? OmniSol can help structure it into a preliminary BOS supply list and quotation.

🌍

Africa / Middle East / Off-grid project? For hybrid inverter + LiFePO4 battery + BOS kits — use to size inverter, battery cable, fuses and AC protection automatically.

Target market

AU/NZ projects: RCM mark required for electrical BOS. Comply with AS/NZS 1170.2 wind zones and AS/NZS 5033 DC wiring. CEC accreditation required for grid-connect.

Array configuration

Rows

Columns

Panel wattageModule orientationSystem DC voltage

Wind standard

Wind region

Terrain category

Roof / mounting type

Panel tilt15°Ground snow load (kN/m²) — 0 if none

System summary

System size

4.8 kWp

12 panels

DC strings

12 panels / string

Est. string current

11.3 A Isc

10.7 A Imp

String open-circuit V

528 V

12 × 44V Voc at STC

Isc and Voc are estimated from panel wattage. Enter actual datasheet values in the Cable and Protection tabs for engineering-grade output.

Wind load preview

Design wind speed

33.8 m/s

75 mph

Governing spacing

1600 mm

Wind governs

Wind uplift pressure

0.888 kPa

Roof factor 1.30

Max cantilever

480 mm

Preliminary estimate

BOM scope

mountingcableprotection

Include battery storage (ESS)

Ready to generate your BOM?

Fill in the tabs for each section, then visit Full BOM & Quote to copy or send to OmniSol via WhatsApp.

Three ways to use this tool

Choose your starting point

Project BOM from Layout

You have array rows, columns, wattage and roof type. Input once and get mounting rails, clamps, DC cables, connectors, combiner boxes, protection and grounding quantities — ready to copy or send via WhatsApp for factory quotation.

Hybrid Solar Kit Quote

You have inverter kVA, battery voltage and string configuration. The kit builder auto-calculates PV cable sizing, fuse ratings, SPD Ucpv and AC breaker — then pushes the combined BOM to the RFQ for consolidated pricing.

Distributor / Stock RFQ

You have a customer inquiry or stock requirement with brand names, model numbers or general specs. Add each line, set quantities, and OmniSol maps to available SKUs, flags MOQ restrictions, proposes alternatives and returns a budgetary FOB price list.

Procurement status legend

What each supply status means in your RFQ

Budget Price Available

Indicative FOB price on hand. Subject to supplier reconfirmation and final order quantity.

Alternative Proposed

Requested item unavailable or out of spec. OmniSol has proposed a compatible substitute — technical confirmation required before order.

MOQ Restricted

Your quantity falls below minimum order quantity. Price is indicative only; surcharge or combined order required to proceed.

Technical Confirmation Required

Spec or certification must be confirmed before pricing. Send datasheet or project standard and OmniSol will verify.

Documentation Pending

OmniSol product is available but a specific certification document (IEC test report, TÜV, UL listing) needs to be forwarded to you.

Not Yet Sourced

Item not yet matched to an OmniSol product family. Submit the RFQ and the procurement team will research availability.

How This Calculator Works

Wind & Snow Load

Design wind speed derived from AS/NZS 1170.2, ASCE 7-22 or EN 1991-1-4. Dynamic pressure q = 0.5 × ρ × V² × roof factor. Snow spacing from rail bending capacity with pitch-adjusted shape factor μ. Governing = min(wind, snow) spacing.

DC/AC Sizing

String count from array layout and system voltage. DC cable selected by estimated Imp, with temperature-corrected resistance (α = 0.00393/°C copper). Combiner selected by string count. Fuse sizing from 1.25 × Isc (IEC 60364-7-712). AC MCB from inverter output current.

BOM & Quote

All hardware quantities assembled into a single BOM with OmniSol SKUs. Copy to clipboard or send directly via WhatsApp to OmniSol's factory team for consolidated export quotation — mounting, cables, protection and storage in one shipment.

PV Cable Voltage Drop →Combiner Box Configurator →DC Protection Coordinator →Battery Capacity Calculator →Wind & Snow Load Calculator →

Solar BOS calculator FAQ

Common RFQ and calculation questions

What is a solar BOS calculator?

A solar BOS calculator generates a preliminary bill of materials for the non-panel parts of a PV project, including mounting hardware, PV cable, connectors, combiner boxes, protection devices, grounding and optional battery storage.

How accurate is the mounting support spacing?

The spacing is a preliminary estimate rounded to 50 mm and capped at 1600 mm. Final certified spacing must be checked against the mounting manufacturer span table or by a licensed structural engineer.

Which markets and wind standards are supported?

The tool includes Australia/NZ with AS/NZS 1170.2, USA/Canada with ASCE 7-22, Europe and global projects with EN 1991-1-4, plus SEA, Middle East/Africa and manual input options.

Can I enter actual module datasheet values?

Yes. Use actual module Voc, Isc and maximum series fuse rating when available. Datasheet values improve string voltage, fuse, SPD, isolator and cable recommendations.

How is string fuse sizing handled?

The preliminary fuse recommendation uses 1.25 x string Isc and checks against the module maximum series fuse rating. Final fuse coordination still needs project-specific electrical review.

How is DC SPD Ucpv selected?

SPD Ucpv is selected from the calculated maximum open-circuit string voltage at the minimum site temperature, then rounded up to the next common SPD voltage class.

What does Market Restriction mean?

Market Restriction marks products that may need a special certified variant, such as UL-listed electrical protection for US projects. OmniSol can help identify or source the correct option during RFQ.

How do I send the BOM to OmniSol?

Open the Full BOM & Quote tab, copy the BOM, or send the project summary through WhatsApp. OmniSol will confirm variants, availability, lead time, packing and freight options.

What if my RFQ only has brand names or incomplete specs?

Use the Distributor RFQ mode and add each line with whatever information you have — brand, model family, approximate spec or just a product category. OmniSol will attempt to match each line to an available SKU and flag any that need further technical clarification before pricing.

Can OmniSol propose an alternative if the exact model is discontinued or out of stock?

Yes. When a requested model is unavailable, OmniSol will mark the line as "Alternative Proposed" and suggest a technically compatible substitute — typically the same product family at a different wattage, voltage or capacity. You review and confirm before the order is placed.

What does "Budget FOB" or "Preliminary FOB" mean on the quote?

Budget FOB is an indicative ex-factory price at the time of inquiry. It is not a firm offer. Final pricing depends on confirmed order quantity, production schedule and currency at the time of purchase order. OmniSol will reconfirm all prices before issuing a formal PI (Proforma Invoice).

What happens when my order quantity is below the manufacturer's MOQ?

Lines that fall below MOQ are flagged as "MOQ Restricted." OmniSol can suggest combining that line with other orders to reach MOQ, applying a small-order surcharge, or substituting with a product that has a lower MOQ. The indicated price at sub-MOQ quantity is indicative only.

Can I get one consolidated quote for inverters, batteries and all BOS hardware together?

Yes. Use the Hybrid Kit mode to build the inverter and battery BOM, then push it to the Distributor RFQ. Add any additional BOS or accessory lines manually. OmniSol consolidates all sourced items into one export shipment with a single set of freight and packing costs.

Technical Guides

PV Cable Sizing & Voltage Drop Guide DC Protection Selection Guide MC4 Connector Compatibility Guide BOS 1500V Selection Guide Wind Load Calculation Guide Solar Panel Tilt Angle Guide

Products & Systems

Mounting Systems PV Cables DC Connectors DC Protection Combiner Boxes Energy Storage

Markets & Services

Need project-specific engineering support?

Free CAD layout, wind/snow load calculations, and BOM review included with project orders.

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