Making Solar Street Light Quotes Comparable
Quotations are only comparable when the technical basis is identical and the cost basis is the same. Normalise pole height, spacing, autonomy days, dimming profile, battery chemistry and usable capacity, warranty terms and documentation, then convert every price to a landed cost at the same delivery point. Only then does the cheapest quote stop being a question of who wrote the shortest scope.
Why two quotes rarely answer the same question
A solar street light is a system, and a system can be built to many different performance points for the same headline description. One supplier quotes an 8 m pole with a 100 W luminaire and three days of autonomy; another quotes the same pole with 60 W and two days, but adds a tiltable bracket and a five-year battery. Both are “8 m solar street lights, 120 units”. The totals may differ by 30% and neither is wrong — they are simply not the same product, and until the differences are written down side by side the comparison is guesswork. The discipline is to build a normalisation sheet before reading the prices.
Normalise the technical basis first
Take the requirement from the specification and force every bid onto it. The rows that most often differ:
- Pole height, wall thickness and galvanizing — a lighter pole is a real saving that shows up as a shorter service life.
- Mounting height and spacing, expressed as a spacing-to-height ratio, with the luminaire output needed to reach the lighting class at that ratio.
- Daily lighting hours and the dimming profile. Convert each profile into watt-hours per night so the bidders’ energy assumptions can be compared directly; a bid that runs 100% all night is a different product from one that dims.
- Autonomy days against a stated worst-month yield, not against an annual average.
- Battery chemistry, nominal voltage, usable capacity and permitted depth of discharge.
- Controller type, current rating and whether remote monitoring is included.
- Panel wattage, cell technology and mounting arrangement (fixed, tiltable, tracking).
Where a bidder has offered a different technical point, the useful response is not to reject it but to ask for a re-price at the specified point. That turns a comparison into a price comparison. Background on the underlying numbers is in battery autonomy for cloudy weeks and MPPT versus PWM controllers.
Move every quote to a landed cost
EXW, FOB, CIF and DDP are not variations in generosity; they are different points in a supply chain, and the price at each includes a different set of costs. Build one landed-cost column with the same components for every bidder:
| Cost element | Note |
|---|---|
| Ex-works price | The only figure all quotes share |
| Packing | Long poles need special packing; check whether it is included |
| Inland transport to port | Often quoted separately for heavy, bulky consignments |
| Export documentation | Customs, certificates of origin, inspection fees |
| Ocean freight and insurance | Volume-driven; poles dominate the measurement |
| Import duty, VAT and clearance | Rate depends on the HS code actually used |
| Inland transport to site | Frequently the largest single line for rural projects |
Price the warranty, not just the box
A five-year luminaire warranty and a two-year one are different products. Compare warranty term by component, the event that starts the clock, what is excluded, and — the line that is usually missing — who pays the freight for a replacement. On a rural project, returning a battery to the supplier can cost more than replacing it locally, so a fair warranty clause states the destination and the cost split. Also check whether the warranty survives a change of owner and whether spares will be available for the same term.
What a low quote usually leaves out
When a bid is far below the others and the technical rows look similar, the difference is normally in the scope rather than the margin. Recurring omissions:
- Packing suitable for long poles, or the cost of loading at the factory.
- Foundation design, anchor bolts or templates, and the separating arrangement between dissimilar metals.
- Battery enclosure, cabling, connectors, glands and earthing.
- Documentation — photometric files, calculations, as-built drawings — treated as a chargeable extra.
- Commissioning support or a factory test record.
- Spare parts and a recommended spares holding.
- A warranty that excludes transport or expires at delivery rather than at commissioning.
Comparing on cost of ownership
For a fleet of installations, the decisive number is rarely the invoice price. A worked comparison with stated assumptions makes the point. Take one pole with a nightly energy demand of 300 Wh, an autonomy requirement of three days and an allowable depth of discharge of 80% for lithium or 50% for lead-acid. Using the battery’s nominal voltage to turn usable energy into amp-hours, a 12.8 V lithium pack would need roughly 300 × 3 ÷ 0.8 ÷ 12.8 ≈ 88 Ah of usable nameplate capacity, while a 12 V lead-acid pack at the same duty would need about 300 × 3 ÷ 0.5 ÷ 12 ≈ 150 Ah. The lithium pack costs more per unit but delivers more usable energy, more cycles and less weight on the pole. Two quotes that look 25% apart on price can reverse once the battery replacement cycle, lifting equipment and pole loading are priced in.
A one-page comparison sheet
The practical tool is a single sheet with one column per bidder and one row per requirement: technical rows first in the specification’s own wording, then commercial rows for the cost build-up, then warranty and documentation. Any row where a bidder has written “included”, “standard” or left the cell blank should be converted into a written commitment before award. If a supplier will not commit in writing at tender stage, that is information in itself. When the sheet is complete, the cheapest compliant bid is usually obvious — and so is the bid that only looked cheap because it answered a smaller question.
How we can help
We are a China-based trading and project sourcing company, not a manufacturer. We review specifications and BOQs, match a product and configuration to your site conditions, source from qualified manufacturers, and manage quality through to pre-shipment inspection. If you are preparing a tender or specification and want a second opinion, contact us.