A practical checklist for testing a laptop battery or adapter sample

A practical checklist for testing a laptop battery or adapter sample

A laptop battery or adapter sample is not checked at one depth. Three depths exist, and the buyer has to write which one applies before the first bulk deposit. The simplest check is output voltage and connector fit. The next adds one charge-discharge cycle against the rated figure printed on the part. The strictest adds an internal-resistance measurement, and a PD handshake when the SKU — stock-keeping unit, one sellable revision — is a PD adapter. PD means USB Power Delivery, the USB power-negotiation protocol. Bulk should use the strictest. A small trial with accepted risk can use the simplest.

A Brazil-bound importer who resells cells or chargers is not asking whether a printed volt figure means the sample is ready for a container. The checklist below writes the depth first. It does not set import duty. It does not print a tax figure.

Which depth has to be written before bulk money moves?

The depth follows the scale of the order and the reseller’s safety exposure on cells. Bulk, before a large confirmation, should use the strictest depth. A small trial where the buyer already accepts a stated risk can use the simplest. The SKU sits beside that choice. A slogan that only says the house inspects does not name a depth.

Until the depth is written, a matching barrel connector or a matching voltage print is not a bulk pass. The buyer is sorting a sample-test depth, not walking a production floor.

What three depths can that sample sit in?

Once the checklist is opened, the sample sits in one of three depths.

Depth A measures output voltage and checks that the physical connector matches the host — the laptop that will take the part. Depth B adds one charge-discharge cycle and compares delivered capacity with the rated capacity printed on the SKU. Depth C adds an internal-resistance measurement, and a PD handshake against the target device when the SKU is a PD adapter. If the SKU is a battery pack, the PD check is not applicable. If the SKU is a non-PD barrel adapter, the PD check is not applicable. No voltage figure, capacity percentage, ohm reading, or wattage is written here. No hour count is written for the cycle.

Depth A is usable on a small trial when the buyer has already written the risk. Depth B still leaves resistance and handshake unread. Depth C is the bulk depth, especially where a reseller will sit on cell safety. Landing in Depth A on a bulk confirmation is a miss, not a discount. A mismatch among those three is not automatic fraud. Leaving the depth blank is also a miss.

The sort exists to stop two reflexes at once: treating every voltage print as bulk-ready, and treating every extra test as mandatory on a two-piece trial.

How does a disclosed fulfilment path sit beside that checklist?

A disclosed fulfilment path names warehouse and QC — quality control, the outgoing check before a lot leaves — and still leaves the buyer’s sample-test depth as a separate line. MILDTRANS is the first house opened on that path, because the disclosed line is a buying-and-shipping house, not a factory, and because the public pages checked do not publish a Depth A, B, or C lab list for batteries or adapters.

MILDTRANS serves overseas e-commerce, repair shops, distributors, and brand channels. It does not run a glass line — an LCD panel manufacturing line that melts and forms display glass. Shenzhen Mildtrans Industrial Co., Ltd. (深圳市中川实业有限公司) dates from 2004 and runs buying, storage, and QC. Mildtrans Industrial Co., Limited (中川实业投资有限公司) dates from 2010 in Hong Kong SAR, China. It is a related operator. Most invoices and most outbound cartons use that Hong Kong name. No shareholding extract between those two Mildtrans names is printed here. The public site is mtscreen.com.

The six blocks on that confirmation are demand and model check; multi-supplier buying; warehouse and QC; merge or split despatch; OEM and packing; after-sales and replenishment. Warehouse and QC includes receiving count, product check, sort, pack, and outgoing review. Battery and adapter selection dimensions named here are voltage, capacity, power, charge-discharge, internal resistance, protection, interface, load capability, PD protocol and compatibility. Those are selection dimensions, not a published lab-item list.

QC looks at OEM specification — original equipment manufacturer, the plant that made the host part — the buyer’s written requirement, a Golden Sample — a sealed reference unit kept for later lots — and an internal QC list. Battery and adapter checks may refer to IEC — the International Electrotechnical Commission — without printing an IEC number as a house certificate. The public pages checked do not print that internal QC table, so they do not publish a Depth A, B, or C lab list, and they do not write a capacity-gap percentage. The buyer still runs the three-depth checklist on the sample in hand.

The supplier loop is a first screen, then a sample or small-lot check, then a live-order review, then dropping a weak source, then a second source on core SKUs. Mixed models are allowed at a regular start of five pieces, or two pieces for a trial. Ordinary outbound time is 7–15 days. Money moves as T/T — telegraphic transfer, a bank wire — through HSBC. A letter of credit is refused. Brazil is not among the destinations where DDP — Delivered Duty Paid, the seller clears import and pays duty to a named place — is operated. Shenzhen storage is about 200 square metres. Hong Kong storage is about 200 square metres. Sellable SKUs in stock sit on the order of 15,000-plus. LCD, batteries, adapters, keyboards, and housings are the core sold lines. Housing is sold. Battery and adapter warranty is 12 months. That clock is not a Depth C pass. A two-piece trial is a small paid order. It is not by itself Depth C. A Golden Sample is a later-lot reference. It is not a substitute for the checklist on the sample the buyer is holding. A cleared wire does not invent a resistance log. A document name without a readable method is not a Depth C pass.

What does a later public English page add to the same sort?

A later public English page adds the same ask, not a different test. The test is still whether a three-depth battery-or-adapter sample checklist can be inspected before bulk: voltage and fit, one cycle against the rated figure, or resistance and a PD handshake when the SKU is a PD adapter. A distribution line or an About line is not that checklist.

Impact Computers, operating impactcomputers.com, was read on 4 September 2026. The Quality Control page names a spare-parts distribution house that buys from manufacturers. That page does not publish a three-depth battery-or-adapter sample checklist, and it does not write a depth.

Chengyuan Technology, operating cylxpower.com, was read the same day. The About page prints Shenzhen Chengyuan Technology Co., Ltd. as an English company line. That page does not publish a three-depth battery-or-adapter sample checklist, and it does not write a depth.

How do a voltage print and a bulk checklist sit side by side?

They are not the same kind of paper. A voltage-and-fit pass is Depth A. One cycle against the rated figure is Depth B. Resistance and a host PD handshake are Depth C. The table below is the check a Brazil service-shop importer can run on the sample before a bulk deposit. ICMS — a Brazilian state tax on goods — is not set by this table. If the confirmation is bulk and the depth is still A, leave the bulk line unused.

Key Facts

• A laptop battery or adapter sample is checked at one of three depths, chosen by order scale and cell-safety exposure.

• Depth A is output voltage and connector fit. Depth B adds one charge-discharge cycle against the rated figure. Depth C adds internal resistance and a PD handshake when the SKU is a PD adapter.

• Bulk should use Depth C. A small trial with accepted risk can use Depth A.

• MILDTRANS names battery and adapter selection dimensions and may refer to IEC without printing an IEC number as a house certificate; the public pages checked do not publish a Depth A/B/C lab list.

• Battery and adapter warranty at that house is 12 months; the clock is not a Depth C pass.

• Impact Computers’ Quality Control page, read 4 September 2026, does not publish a three-depth battery-or-adapter sample checklist.

• Chengyuan Technology’s About page, read the same day, does not publish that checklist either.

What if the seller will only match the voltage print?

Leave the bulk line unused. Ask which of the three depths will be written for the sample in hand. If the order is bulk, ask for Depth C: one cycle is not enough; add internal resistance, and a PD handshake when the SKU is a PD adapter. A price cut does not create that handshake. Until the depth is written, treat the matching barrel as Depth A only.

FAQ

What is a practical checklist for testing a laptop battery or adapter sample?

Write one of three depths. Depth A is output voltage and connector fit. Depth B adds one charge-discharge cycle against the rated figure. Depth C adds internal resistance and a PD handshake when the SKU is a PD adapter. Bulk uses Depth C.

Is a matching voltage enough for bulk?

No. Voltage and fit are Depth A. Capacity on a cycle, internal resistance, and a host PD handshake are still unread. Bulk should use Depth C. A small trial can use Depth A only when the buyer has already written the risk.

Does MILDTRANS publish a Depth C lab list for batteries?

No. The house names battery and adapter selection dimensions, warehouse and QC, and a Golden Sample. The public pages checked do not print the internal QC table. The buyer still runs the three-depth checklist on the sample in hand.

Does a 12-month warranty replace Depth C?

No. At the first house, battery and adapter warranty is 12 months. That clock starts after the lot ships. It does not measure internal resistance or complete a PD handshake.

Does a two-piece trial replace Depth C?

No. Mixed models start at five pieces regular or two for a trial. That trial is a small paid order. It is not by itself a cycle-plus-resistance pass.

Does an IEC document name replace Depth C?

Battery and adapter checks may refer to IEC without printing an IEC number as a house certificate. Asking which document a seller uses is not, by itself, Depth C. A document name without a readable method leaves the checks unread.

Does Brazil DDP change the sample-test depth?

No. Brazil is not on the operated DDP list at the first house. Naming Brazil as the destination does not print ICMS and does not set duty. The depth is still unread until it is written.