How to choose a charging block: wattage, connector, polarity

Three parameters that determine charger compatibility

1. Wattage (W) — typical values are 45W, 65W, 90W, 130W, 170W. A charger with

lower wattage than the laptop needs under load forces the system to simultaneously draw power from the mains and discharge the battery — this accelerates battery wear.

1. Connector type — a round plug (in several diameters that look almost

identical but are not interchangeable), or USB-C Power Delivery (newer models after ~2018-2019).

1. Polarity — for round plugs, "positive inside / negative outside" or vice versa.

Why a charger with higher wattage is fine, but one with lower wattage is not

A laptop consumes exactly as much current as it needs — a higher wattage charger simply "can provide more." But a charger with insufficient wattage is a real problem: under peak loads, the system is "helped" by the battery, which wears out faster than a normal charge/discharge cycle.

USB-C chargers — not all are the same

Not every USB-C cable/block supports Power Delivery at the required wattage. A cheap 20W USB-C block will charge a phone but won't power a laptop that needs 65W.

Typical customer mistakes

• "I already have a charger with the same plug" — the plug diameter can be

visually almost identical while having a different actual size.

• "A charger from the same brand will always fit" — a single manufacturer

produces several incompatible connector standards in parallel depending on the product line and year.

• "The main thing is that it fits and the indicator lights up" — incorrect

polarity is one of the common causes of motherboard failure.

How to choose the right charger

The most reliable way is to search by the exact laptop model or by the MPN of the original charger.