The Same Question, Different Answers
Send one request for quotation to three lithium battery suppliers and three different documents come back: different capacities stated at different rates, different BMS descriptions, different freight assumptions and different warranty wording. Comparing them line by line on the unit price is the fastest way to a bad decision, because each quote answers a slightly different question. Fair comparison starts with normalizing the offers so that all of them answer the same question, and only then reading the prices.
Align the Technical Baseline First
Before any number is compared, check that the products described are actually comparable:
- Same voltage class and same nominal energy, not just the same amp-hour figure at different voltages
- Same continuous discharge current, and clarity on whether the limit is the BMS limit or the cell limit
- Same communication interface, with the protocol document named, if the packs must talk to an inverter
- Same protection feature list from the BMS, requested in writing from each supplier
If the baselines differ, either request a re-quote against one common specification or accept that you are comparing different products and adjust expectations accordingly. A re-quote against your written specification is the cleaner path and costs one email.
Read the Test Conditions Behind the Figures
Capacity and cycle life numbers are conditional statements. A 200 Ah figure means little until the discharge rate, the temperature and the cutoff voltage are stated, and a 6,000-cycle claim means little until the depth of discharge and the end-of-life capacity level are stated with it. Bring every quoted figure back to its conditions and compare conditions, not numbers. A supplier who states test conditions openly is easier to trust than one whose figures float free of them, even when the floating figure is higher.
Compare the Scope of Supply
The unit price buys a defined bundle, and the bundle varies. Check each quote for what is included: interconnect cables and lugs, mounting brackets, communication harnesses, manuals and their languages, the packaging definition, and any display or monitoring accessories. A quote that includes brackets and a printed manual is not directly comparable to one that prices the bare pack, and the difference surfaces later as a purchasing line on your side. List the bundle from each offer in a table and price the gaps yourself.
Compare the Commercial Frame
Several commercial terms change the real cost without changing the unit price:
- Trade term, and with it who pays freight, insurance and destination charges
- Payment terms, which carry a financing cost worth quantifying for large orders
- Warranty term together with its conditions, as covered in the warranty article of this guide
- Certificate copies provided per model, and the supplier's willingness to state certificate scope in writing
- MOQ and lead time, which shape your inventory cost more than the unit price does
- Tooling and engineering charges for any OEM customization, and how they are amortized
Convert to Cost per Usable Kilowatt-Hour
Once the baselines and the bundles match, a single figure brings the offers together: the cost per usable kilowatt-hour over the warranted life. The calculation is simple. Take the unit price, divide by usable energy at the depth of discharge the project will run, and divide again by the number of cycles the supplier documents at that depth, weighted by the warranty conditions. Freight and duties land in the numerator as part of the delivered cost. The offer with the lowest result is not automatically the winner, but the ranking it produces is at least comparable, and it exposes offers that look cheap per unit and expensive per delivered kilowatt-hour.
Two habits keep the comparison honest over time. First, ask for a validity date on every offer and re-confirm the price in the proforma invoice, because battery material markets move, and a quote that drifts between documents is a sourcing risk in itself. Second, keep the filled comparison table as a living file: when a supplier revises an offer after a volume change, update the same rows, so the project history shows why the winner won and what the runner-up would have needed to match.
Red Flags in a Quotation
- Cycle life with no depth of discharge or end-of-life definition
- A BMS described only as "advanced" with no protection list offered in writing
- Certification claimed at family level with no willingness to send per-model copies
- A warranty number with no start point, conditions or claims process
- Prices valid for an unstated period, or terms that change between the quote and the proforma invoice
A Comparison Table You Can Reuse
| Line | What to record from each offer |
|---|---|
| Model and nominal energy | Voltage, amp-hours, kilowatt-hours as stated |
| Test conditions | Rate, temperature, cutoff for capacity; depth of discharge and end-of-life for cycles |
| BMS | Continuous and peak current, protection list, communication protocol |
| Scope of supply | Cables, brackets, manuals, packaging definition |
| Compliance | Certificates held, copies provided, declaration scope |
| Commercial terms | Trade term, payment, MOQ, lead time, warranty with conditions |
| Delivered cost | Unit price plus freight and duties, per usable kWh over warranted life |
Where YueQi Fits
YueQi New Energy answers quotation requests with the datasheet, the BMS protection list, the certificate scope and the commercial terms attached, so the comparison table above can be filled from the offer itself. Quotations for the 12.8V, 25.6V and 51.2V pack families, home storage units and portable power stations are issued with their assumptions stated and are confirmed in writing, which is what makes them comparable against any other offer on your desk.
Summary
Quotations are comparable only after they are normalized: one specification, stated test conditions, a listed scope of supply and a written commercial frame. Then convert the results to delivered cost per usable kilowatt-hour over the warranted life and read the red flags before the price. The supplier who documents the offer well is usually the supplier who documents the product well, and that correlation is the quiet finding behind most successful sourcing projects.
Next step
Send your application, target specification and estimated quantity with your inquiry, and we will confirm matching products, samples and document requirements in writing. See the product lines or request a quote.