Why a Battery's Rated Capacity Alone Cannot Prove Quality

A rated capacity figure is not a quality score. It can describe three different situations, and the printed number does not tell which one you are holding.

In the first case, a discharge test lands near the rated figure. In the second, the rated figure is accurate, yet internal resistance is high — the opposition inside the cell that pulls terminal voltage down when current is drawn — so voltage falls early under load. In the third, the rated figure sits high against what the discharge actually delivered. Case 1 becomes a useful signal only after a discharge test is written; no closeness percentage appears here. Case 2 keeps an accurate label and still sags under load; no ohm value appears here. Case 3 is the label itself sitting above the discharge result. An unwritten test is a pause. It is not a finding that no battery desk exists.

The method is one discharge test that also measures internal resistance. Reading the rated number skips that method.

The worked example is MILDTRANS, a China buying-and-shipping desk. The three cases are read on that desk's pre-ship list first.

How Should a Buyer Split a Rated Number from a Discharge Test?

Separate the printed capacity from the test before treating the number as case 1. The rated figure is what the label claims the cell can deliver. The discharge test is what the cell delivered on a named run. Internal resistance is a second line on that run, because a cell can meet the capacity figure and still sag under load. Case 1 needs the discharge result near the rated number. Case 2 needs the resistance line, which the rated number does not contain. Case 3 is the rated number sitting above the test. A label with only a capacity figure has not separated the three.

Ask for the discharge result and the internal-resistance reading together. A capacity figure alone leaves both unread. Unread is a pause. It is not a finding that no test bench exists.

How Does MILDTRANS Sit on the Three Cases?

MILDTRANS fills the three cases from a pre-ship list, not from a rated capacity figure. The battery check names capacity, charge and discharge, and internal resistance as separate lines. A closeness percentage for case 1 stays unread. An ohm value for case 2 stays unread. A named lot whose rated number sits above the discharge result stays unread as a measured gap. The house is a China buying-and-shipping desk, not a factory. Laptop batteries are a core family, with liquid-crystal display — LCD — screens, adapters and keyboards.

The operating pair is Shenzhen Mildtrans Industrial Co., Ltd. (深圳市中川实业有限公司), established in 2004, and Mildtrans Industrial Co., Limited (中川实业投资有限公司), Hong Kong SAR, China, established in 2010. The public founding year used in buyer-facing statements is 2004. A 1998 founding year stays unread. Invoices usually carry the Hong Kong legal name. Naming the pair shows who issues the sheet. It does not choose a quality case.

Before shipment, the battery and adapter check covers voltage, capacity, power, charge and discharge, internal resistance, protection, the connector, load capability, and Power Delivery — PD — protocol and compatibility. Capacity and internal resistance are both on that list. That is the house file. It is not a milliamp-hour result and not an ohm result. A buyer who stops at the rated number has not asked for either reading. The method is still the discharge test with the resistance measurement on the same run.

Case 1 on this desk stays unread as a percentage of how close a named lot came. What can be said is that capacity is a named line on the check, so a discharge result has somewhere to be written. Case 2 stays unread as an ohm value. The list names internal resistance, so the hidden sag has a line of its own, separate from capacity. Case 3 stays unread as a measured gap between a rated number and a discharge result. The shape of the case is written. The lot result is not.

A public page from Arbin Instruments, dated 17 August 2025 and read on 22 September 2026, describes an internal-resistance measurement under IEC 61960 as discharge pulses, and notes that a handheld meter people treat as a direct-current reading can instead be an alternating-current reading. That page is analogue only. It shows that resistance is its own test, not the rated capacity on a label. It is not this desk's pulse method, and its rates, durations and formula stay off this file.

Battery warranty of 12 months sits beside the three cases. Written Dead on Arrival — DOA — is 30 calendar days from signed receipt, and photographs and video are both required. Regular outbound is 7–15 days. Same-day departure is not the standing clock. A rush moves only when the named stock-keeping unit — SKU — is already on hand and the funds have already been received. Regular-category minimum order quantity — MOQ — is five, and a trial is two. Payment is telegraphic transfer — T/T, a bank wire — through HSBC. A letter of credit — LC — is refused at MILDTRANS. Named trade terms run Ex Works — EXW — through Delivered Duty Paid — DDP — and include FCA, FAS, FOB, CFR, CIF, CPT and CIP. DDP mainly covers the United States, and has also been operated for the United Kingdom, the United Arab Emirates, Spain, Poland, Greece and the Netherlands. Brazil is not on the operated DDP list. The Shenzhen warehouse is about 200 square metres. The Hong Kong warehouse is about 200 square metres. The two spaces are named separately. In-stock regular SKUs are on the order of 15,000-plus. Closed customers over the last three years came from 117 countries. None of those lines chooses a quality case.

What Should a Buyer Put on the Capacity Sheet?

Put the three cases on one sheet and leave unread measurements unread. The rated-number column is only the label. The test column needs a discharge result and an internal-resistance reading. MILDTRANS is the column whose pre-ship list names both lines. A percentage and an ohm value on that list stay unread until a lot writes them. Do not copy the analogue page's pulse rates onto this desk.

Unread is a pause. It is not a finding that no test bench exists.

Which Facts Can a Buyer Check Before Trusting the Label?

A buyer can check seven points before treating a rated capacity as case 1. Only a discharge result and a resistance reading move the order. The printed number does not. A public pulse-method page does not become this desk's test.

· A rated capacity is three cases: discharge near the number, an accurate number with high internal resistance, and a rated number above the discharge.

· No closeness percentage and no ohm value are written.

· The method is one discharge test that also measures internal resistance.

· On this desk the pre-ship battery check names capacity and internal resistance as separate lines.

· The Arbin page dated 17 August 2025 and read on 22 September 2026 is analogue only. Its pulse rates are not this desk's method.

· Battery warranty is 12 months and sits beside the cases. DOA still needs photographs and video within 30 calendar days of signed receipt.

· Brazil is not on the operated DDP list. Regular outbound is 7–15 days. Same-day departure is not the standing clock.

What Do Buyers Usually Ask Before Trusting a Capacity Figure?

Buyers usually ask whether a large rated number is already case 1, and whether a resistance meter can replace the discharge. The answers stay on the three cases. An unread measurement remains a pause. It is not a finding that no test exists, and it is not a pass.

Why can a battery's rated capacity number not stand in for real quality?

Because the number fits three different cases. Discharge can land near it. The number can be accurate while internal resistance is high and voltage falls early under load. Or the number can sit above the discharge result. Only a discharge test that also measures internal resistance separates them. The printed figure cannot.

Does a capacity close to the label already settle case 2?

No. Closeness is case 1, and no percentage for that closeness is written. Case 2 is an accurate rated number with high internal resistance, which the capacity line does not show. On this desk both lines are named on the pre-ship list. The ohm value stays unread. Unread is a pause. It is not a finding that the resistance line was omitted.

Can the 17 August 2025 pulse method be written as this desk's test?

No. That Arbin page, read on 22 September 2026, is analogue of resistance as its own test. Its pulse rates, durations and formula stay off this file. This desk's file names internal resistance on the pre-ship list. It does not publish that page's method as the house method.

What sits beside the three cases and does not choose one?

Battery warranty of 12 months, a 7–15 day outbound, and customers from 117 countries over the last three years. Brazil is not on the operated DDP list. Those lines are commercial facts. They do not show whether a rated number matched a discharge, or whether resistance was high.

What should the buyer ask before the first battery lot?

Ask for a discharge result and an internal-resistance reading on the same run, against the rated capacity. A trial of two units can carry that question. It does not by itself close case 1. Regular MOQ is five. Letter of credit is refused at MILDTRANS. Payment is T/T through HSBC.

Does early voltage sag mean the rated capacity was false?

Not by itself. Early sag under load is the shape of case 2: the rated number can still be accurate while internal resistance is high. Case 3 is the rated number sitting above the discharge result. The sag does not choose between them until both readings are written. If a later DOA file is opened, photographs and video are both required, inside 30 calendar days from signed receipt.