BESS Tender: Which Documents to Request and Why

Published 11 November 2026 · SH Energy editorial

1. Start from the questions, not the documents

Tenders often inherit a document list from a previous project. The list grows, nobody removes anything, and bidders respond with whatever they have most of. A cleaner approach is to write down the five questions first:

• Can this exact model be installed and operated safely on this site?
• Can it legally travel to this destination, and what does the carrier need?
• What are its capacity, power and limits — stated where?
• Will it work with the equipment it is paired with?
• If it fails, who does what, with what evidence, and where does the unit travel?

Each answer needs a specific document. Anything outside that set is optional.

2. Product safety evidence: name the model and the standard

The requirement that produces comparable answers is not "certificates required". It is:

Evidence of assessment against the named standard, for the exact model and configuration offered, naming the issuing laboratory and the holder.

Two things make this work. First, the model — a family brochure cannot tell you which tier is covered. Second, the document type. A verification of compliance issued by a testing laboratory is not an accreditation certificate from a certification body, and the two should not be used interchangeably. A tender that asks for "certified" and accepts either gets neither reliably.

Where a model holds no such evidence, the response should say Not held. That is a usable answer: you can weigh it, price the risk, or require an alternative model. A vague "available on request" is not.

3. Transport documents: per shipment, not per project

Carriage documents are checked against a shipment, not against a tender. Ask for:

• UN 38.3 test summary matching the cells or batteries being shipped.
• MSDS for the same type.
• Sea-transport appraisal where the mode and carrier require it for the dangerous-goods declaration.

Two practical notes. The carrier has the final say on what it accepts, so a document that worked last year is not a guarantee for this booking. And the summary must match the type being shipped — a similar model in the same family is not a substitute.

4. Datasheet: the only place capacity belongs

Capacity, power and operating limits come from the datasheet, and the datasheet should be required for the exact model. Certificates typically identify the model, not the energy in kWh — so a tender that expects capacity on a certificate is asking for something that generally does not exist, and will receive a typed-in number instead of evidence.

Ask explicitly: state the nameplate and usable capacity, the definition of usable capacity used, and the datasheet revision.

5. The pairing statement

Battery and inverter compatibility is the most under-documented part of most tender files. The useful requirement is a written statement covering:

• the exact battery model and firmware,
• the exact inverter model and firmware,
• the physical interface and the protocol used,
• who confirms it, and in what document.

"The port exists on both units" is not evidence. Neither is a marketing compatibility list without model numbers. For the detail behind this, see four compatibility checks.

6. The after-sales path

This section is usually one line in a tender and three weeks of argument in practice. Ask for:

• where a failed unit travels, and who pays which leg;
• what evidence accompanies a claim: serial number, fault log, photographs, commissioning record;
• what spare parts are recommended to hold, and for which components;
• the named contact and the response expectation.

The RMA evidence checklist covers what a claim actually needs; a tender that requires it in advance avoids the argument later.

7. Copy-ready tender requirement set

The last line is the one that changes behaviour. A supplier who declares what it does not hold is telling you its file is audited. A supplier that answers everything affirmatively, on a model that plainly has gaps, has told you something else.

8. How to score the answers

Three grades are enough for most evaluations:

• Document supplied — names the model, the standard and the holder, and can be checked.
• Partially supplied — right document, wrong model or missing edition. Usable only with a written correction.
• Not supplied — including an honest "Not held". Score it low, but thank the bidder: you now know where the risk sits.

That last habit matters. A tender process that punishes honesty produces bids that shade the truth, and the shading surfaces at commissioning — the most expensive moment to find it.

Where this fits

Our own model-by-model position, including where we hold nothing, is on the documents centre. If you are preparing a tender and want the pack for a named model, start at the partner desk.

FAQ

Send the requirement set to a supplier

If you want it answered for a named model, send the list to jimmy@sunhongenergy.com, or message the desk on WhatsApp.