A solar bill of materials (BOM) has 12 core component groups: modules, cells, wafers, inverters, batteries, glass, aluminium frames, mounting structures, cables and connectors, junction boxes, backsheets, and EVA encapsulants. For each, verify the technical spec and the required certification (ALMM, BIS, IEC or MNRE) before ordering, because a single non-compliant line can hold up the entire shipment at customs.
”- The BOM splits into three layers: generation (modules, cells, wafers, inverters, batteries), structural (glass, frames, mounting), and connection (cables, junction boxes, backsheets, encapsulants).
- Balance-of-system parts cause most customs and quality failures because their specs are the least scrutinised.
- Certification requirements differ by component: modules need ALMM + IEC, inverters need MNRE, most BOS parts need IEC/BIS.
- Sourcing the full BOM as a single RFQ, rather than component by component, cuts lead time and lets you finance the whole order at once.
What is a solar BOM?
A solar bill of materials is the complete list of physical components required to build and connect a solar installation. It runs from the parts everyone knows, the modules and inverters, down to the parts nobody talks about until one fails inspection: the junction boxes, backsheets and encapsulants.
For an EPC or importer, the BOM is not a shopping list, it is a risk map. Every line has a technical specification and, for imports into India, a certification requirement. Get the spec wrong and the component underperforms on site. Get the certification wrong and the shipment can be refused at the border or disqualified from a tender. This checklist walks all 12 component groups, organised into the three layers of a working system.
Layer 1: The generation components
These convert sunlight into usable power. They are the highest-value lines and the most scrutinised on certification.
Solar modules
Solar modules are the headline line item. Verify the wattage class, the cell technology (TOPCon, PERC or HJT), the bifaciality if relevant, and, critically, the ALMM listing. For any government-linked or scheme project in India, an unlisted module is not eligible, no matter how good the price.
Solar cells and wafers
If you are buying upstream, solar cells and wafers carry their own checks: M10 versus G12 wafer format, efficiency bin, and defect grade. Format mismatches cascade into module assembly problems, so lock these early.
Inverters
Inverters must match your plant topology, string inverters for distributed rooftop and C&I layouts, central inverters for utility scale. For India, MNRE approval is the gate. Also confirm the MPPT count, IP rating and grid-code compliance for your state.
Battery and storage
For hybrid or storage projects, battery and storage systems need a chemistry decision (LFP for safety and cycle life, NMC for density), plus IEC certification and a matched BMS. Undersized or mismatched storage is a common and expensive site-level mistake.
Layer 2: The structural components
These hold the system together and to the ground. Under-specifying here is what causes field failures years later.
- Solar glass: verify AR (anti-reflective) coating, thickness (typically 3.2mm), and tempering. Low-quality glass drags down yield across the whole array.
- Aluminium frames: check the anodising thickness and the profile. Under-anodised frames corrode in coastal and high-humidity sites.
- Mounting structures: confirm galvanisation (hot-dip vs pre-galvanised) and the wind-load and seismic rating for your location. This is a structural safety item, not a commodity.
Layer 3: The connection components
The cheapest parts on the BOM, and the ones that cause the most rejected shipments, because their specs are easy to overlook.
- Cables and connectors: TUV-rated DC cable, correct cross-section for the current and run length, and matched connectors (mismatched connectors are a fire risk and a warranty void).
- Junction boxes: IP68 rating, correct diode configuration, and thermal tolerance.
- Backsheets: PVDF or equivalent, verified for UV and hydrolysis resistance. Cheap backsheets are the single biggest cause of premature module degradation.
- EVA and encapsulants: standard EVA for monofacial, POE for bifacial and high-humidity environments to prevent PID (potential-induced degradation).
The certification quick-reference
Rather than memorise which mark applies where, use this table when vetting any quote. If a supplier cannot produce the relevant certificate, treat the line as unverified.
| Component | Primary certification | What it proves |
|---|---|---|
| Modules | ALMM + IEC | Eligibility + performance standard |
| Inverters | MNRE + IEC | Scheme eligibility + safety |
| Cells / Wafers | IEC | Performance standard |
| Glass / Frames / Mounting | BIS / IEC | Safety + conformance |
| Cables / Junction boxes | TUV / IEC / BIS | Safety + fire rating |
| Backsheets / Encapsulants | IEC | Durability standard |
How to source the full BOM without the chaos
The traditional method, emailing a dozen suppliers per component and reconciling quotes in a spreadsheet, is where weeks disappear and specs slip. The modern method is to post one RFQ for the entire BOM, receive verified quotes in 24-48 hours, and compare like-for-like on price, lead time, spec and certification in one view.
Where you buy matters as much as what you buy. Duty and lead time differ by corridor, China, Vietnam, Thailand, Malaysia and Indonesia each land at different landed costs once duty and freight are added. And because the whole BOM sits in one order, you can attach financing to it: PO Finance funds up to 100% of the order value with a 48-hour decision, so the shipment moves without draining your working capital.
- One RFQ creates competition across every line at once
- Freight consolidated, duty and financing optimised once
- Certification checked per component before you accept
- Lead time compresses to a single 24-48h quote cycle
- A dozen supplier threads to chase and reconcile
- Freight and duty paid piecemeal, rarely optimised
- Specs slip on the lines nobody double-checks
- Weeks lost, and the quoted price often moves before you buy
Source and finance the entire BOM from one RFQ
VyaparCred turns the 12-component checklist above into a single sourcing action. Post one RFQ and reach verified suppliers across every component group and corridor at once, with certification and landed cost shown on every quote.
One RFQ covers the full BOM, modules to encapsulants, so nothing is sourced in isolation or missed.
Every quote shows the certification status (ALMM, IEC, MNRE) and the landed cost, not just the sticker price.
Attach financing to the accepted order and fund up to 100% of the BOM with a 48-hour decision.