4pin Magnetic Charging Cable | 7.62 mm Pitch

Overview

A 4pin magnetic charging cable uses four spring-loaded pogo contacts in a magnetic head to carry power and, depending on the device, a data pair or an identification line. The four-contact layout is common on smart watches, small wearables and handheld devices that need more than a simple two-wire charge path. We build the 4pin magnetic charging cable as a made-to-drawing volume part, with 7.62 mm pitch as the most frequently requested interface and a 1 m lead as the reference length. Indicatively, that reference build is about US$0.40 per unit at 10,000 pieces FOB, confirm per RFQ. This page covers the interface dimensions, the pin layout, the protection options and the specification points you need to settle before a quote.

What a 4pin Magnetic Charging Cable Does

Two magnets in the head align and hold it against the device, while the four pogo pins between them compress onto flat contact pads. On a two-wire charge design the extra contacts may be paralleled for current or used for device detection; on a four-wire design they may carry USB data, a thermistor signal or an ID resistor. The magnetic attachment removes the need for a plugged port on the device, which is why it shows up on sealed and wearable products. The USB end of the cable follows the published specifications of the USB Implementers Forum, and the head is built to the mating drawing or an approved sample. A 4pin magnetic charging cable is therefore specified from the device side first, not from the cable catalog.

7.62 mm Pitch and Connector Compatibility

Pitch is the distance between the outer contact centers, and 7.62 mm is the interface most often requested for this class of watch charger. It is a widely used spacing, not a universal standard, so it must be confirmed against the device. A head with the right pitch can still fail to seat if the magnet positions, the housing outline or the pin diameter differ. We ask for one of three things: the device contact drawing, a physical sample of the existing charger, or the device itself. From any of those we measure pitch, pin count, pin diameter, magnet polarity and head outline, then build a mating head. Where a program spans several watch models, we can key the heads differently so the wrong charger cannot be attached, or standardize on one head across models to keep the unit price down.

4pin Magnetic Charging Cable Specifications

The table below is the reference configuration behind the indicative price. Every value follows the drawing, so a different pin assignment, length or jacket is quoted rather than treated as out of scope.

Pogo Pin Layout and Polarity

Four contacts give you more freedom than two, and more ways to get it wrong. The pin assignment has to be fixed in writing: which pins carry VBUS and ground, which carry data or ID, and whether any pin is left unused. Reverse polarity on a charge pair can damage the device, so the drawing carries the assignment and the first article is checked against it before a volume run. Pogo pins are spring-loaded and plated; we specify travel, contact resistance and plating thickness from the drawing, then verify pin travel and continuity on the production line. If your device uses a detection resistor on one contact, tell us the value — it is a component we place in the head, not something the cable can infer.

Short-Circuit Protection and Charging IC

A magnetic head can land on keys, a coin or a metal table edge while live. Without protection, that can bridge contacts and put current where it does not belong. The usual answer is a protection IC in the head or in the cable assembly that limits current and shuts down on a short, plus a physical recess around the pins so casual contact is less likely. This is quoted as a build option rather than assumed, because it changes the bill of materials and the head overmold. Where the device negotiates charging over USB-C, we build to the power level the device actually requests rather than sizing the conductor from a marketing wattage. Tell us the charge current and the protection behavior you need and we will state it on the drawing.

Indicative Pricing by Specification

The reference 1 m, 4 pin, 7.62 mm build is indicatively about US$0.40 per unit at 10,000 pieces FOB. From that baseline, four changes move the number: a protection IC adds component and assembly cost, a new head geometry adds a tooling charge, a longer or heavier-gauge cable adds copper, and retail packaging adds printing and labor. USB-C with an E-marked cable is a different build and quoted separately. We publish the reference point so the specification trade-offs are visible, then confirm the final figure in writing. All prices on this page are indicative, quoted FOB, and must be confirmed per RFQ. Unit price varies with connector, length, jacket, packaging, tooling and the compliance documentation required for the destination market.

Market Price Context

A survey of publicly listed prices in October 2026 found single magnetic charging cables at roughly US$2.20 to US$5.00 in retail listings, and roughly US$0.45 to US$3.00 each in B2B supplier listings at minimum order quantities of 1,000 to 5,000 pieces. The lowest published B2B tier we found was around US$0.45 at 5,000 pieces. Our indicative US$0.40 at 10,000 pieces undercuts those published tiers because the program is priced on volume and tooling reuse, not on a catalog margin. These figures are observations of public listings at a point in time, not offers, and they vary with specification and packaging.

Cable Construction and Materials

The cable itself is stranded copper in a PVC or TPE jacket with a molded strain relief at each end. The head overmold holds two magnets and the four-pin array; the USB end can be USB-A or USB-C. Jacket color is matched to order, and a braided or low-smoke compound is quoted as an alternative. Head geometry, keying and magnet strength are set from the device sample. Minimum bend radius and pull strength are agreed on the drawing and checked on the first article, because a charger that is tugged off a bedside table every morning puts more wear on the strain relief than a cable that stays plugged into a wall.

Custom Lengths, Colors and ODM

Length is cut to order; 1 m is the common charging-lead length and the basis of the reference price, but 0.2 m to 5 m and coiled versions are available. Jacket color, head color, printed logo, USB plug style and packaging artwork can all be set for an ODM program. Where the head geometry is new, our toolroom quotes the mold separately and states the cost before any tooling spend; 3,000+ tooling sets have been built since 2012 and 100+ molds remain active. Prototype runs of 1 to 50 pieces allow first-article approval, after which the volume run follows the approved sample. If you are replacing an existing supplier, send the current cable and we will match it to a sample.

Quality Control and Testing

Every cable is checked for continuity, short circuits and correct pin assignment before packing. The head is mated against a reference device or test fixture to verify seating and pin travel. Lot documentation can include insulation resistance, hi-pot results and strain-relief pull-test records when specified. For four-pin designs we recommend a dedicated fixture that exercises every contact, since a cable can pass a two-wire continuity check with a data pin open. Test methods and limits are agreed in writing before production so the report matches the drawing rather than a generic checklist.

Packaging, MOQ and Lead Time

The reference price assumes bulk packing in PE bags and export cartons. Retail boxes, header cards, barcode labels and custom print are separate options. Prototype quantities of 1 to 50 pieces are available; volume pricing typically begins at 10,000 pieces and moves with the connector and tooling. Lead time is stated in the RFQ response, since it depends on whether tooling exists and on the test and documentation package for the destination market. All prices on this page are indicative, quoted FOB, and must be confirmed per RFQ. Unit price varies with connector, length, jacket, packaging, tooling and the compliance documentation required for the destination market.

Frequently Asked Questions

Is 7.62 mm a standard pitch? It is a commonly used interface for watch chargers, not a universal standard. Confirm it against your device drawing or sample before ordering.

Is the US$0.40 price fixed? No. It is an indicative FOB figure for the reference 1 m build at 10,000 pieces; all prices are confirm per RFQ and change with protection IC, tooling, length and packaging.

Can the four pins carry data? Yes, if the device design calls for it. The pin assignment must be stated on the drawing, including any ID resistor value.

Do you offer short-circuit protection? Yes, as a quoted build option in the head or the cable assembly.

Can I get USB-C instead of USB-A? Yes. USB-C builds, including E-marked cables for higher power, are quoted separately.

Related Cable Ranges

This build is part of our Low-Cost Cable Assemblies line for volume ODM programs. For broader power-lead options see DC Plug Power Cables, and for build-to-print looms see Custom Wire Harnesses. Also compare the kids smart watch magnetic charger and the bulk magnetic charging cable supply program. Request a written quote through the RFQ form.