Spec Sheet vs RFQ — What's the Difference and Why Both Matter

Buyers often mix up two documents: the spec sheet and the RFQ. They are not the same thing. One tells a supplier what to build. The other tells them how to quote. Confusing the two is one of the most common reasons buyers get 10 different "same product" quotes that cannot be compared.

The spec sheet (technical document)

This is your product definition. It says: "This is what we want." It includes cell chemistry and capacity (for example LFP 280Ah or 314Ah), BMS voltage, current and SOC range, enclosure IP rating, dimensions and weight, operating temperature range, required certifications, connector types and cable lengths.

The spec sheet is engineering. It should be written by you or your engineer, not by the supplier. If the supplier writes your spec sheet, they will write it to match what they already make — and you will get back a quote for their product, not yours.

The RFQ (commercial document)

This is your request for price. It says: "This is how we want to buy." It includes quantity and target delivery date, delivery term (FOB, CIF or DAP), destination port, payment terms, required delivery schedule, and submission deadline.

The RFQ is procurement. It should be written by you, not by the supplier. If the supplier writes your RFQ, they will write it to make their quote look best — FOB their factory, 30-day lead time, 50% deposit — and you will not be able to compare.

Why both matter

Without a spec sheet, the supplier will quote whatever product they have in stock, and you will get 10 different products all called "100kWh." Without an RFQ, the supplier will quote on their own terms, and you cannot compare price, lead time or payment across suppliers.

The workflow

Write your spec sheet first (what you want). Then write your RFQ (how you want to buy). Send both to suppliers together. Compare apples to apples. If a supplier asks you to fill in the spec sheet for them, treat that as a red flag — they are not engineering your product, they are selling you what they already make.

Use this as a procurement framework, not as engineering, legal or tax advice. Always confirm spec, price and timing in writing.

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