What is the key component of a laptop? You might think of the screen, the hard drive, or perhaps the RAM. All of these are essential, of course, but the one part without which the whole machine simply switches off is:
… the external power supply!
The reality is that if the power adapter stops working, your entire laptop becomes nothing more than an unusable paperweight.
Chargers are rarely talked about until the urgent need to buy one suddenly appears. The three main reasons that trigger this urgency are:
- The original charger has permanently failed.
- The adapter has been lost (left behind when travelling, and so on).
- You need a second adapter for use at a second home or at the office, so you don’t have to carry the main charger around.
Whatever your exact reason for buying a new adapter, you will face a tricky choice that means understanding amperage, voltage, power rating and connector size.
Why is it so important to choose the right new adapter?
The market is flooded with all kinds of AC adapters, but compatibility is never guaranteed. The adapter you choose must be a perfect match for the brand and the exact model of your laptop.
You don’t have to buy a charger that carries your laptop manufacturer’s logo (for example, Dell). Specialist companies such as AcBel Polytech, LITEON and DELTA offer very high quality replacement solutions.
Your original adapter may even have been manufactured by one of these subcontractors. To guarantee trouble-free interchangeability, it is vital to focus on the technical specifications of the adapter rather than the brand name.
The technical specifications you must compare before buying
You need to compare the following parameters to be sure you are buying the right charger.
Input voltage
The input voltage is the mains voltage that the adapter receives from the wall socket. Around the world, this ranges from 110V to 240V. These values are printed on the back of the charger, usually as 100V – 240V. This means your adapter can work with most mains power systems worldwide.
If you buy within the EU, the charger will very likely support 110V-240V, as this is a regulatory requirement. However, if you buy outside the EU, the adapter may only be suitable for the local power grid. It is therefore crucial to read the label carefully.
Output voltage
The output voltage is the single most critical indicator. It is shown just below the input values and tells you the voltage (V) supplied to the laptop (often 19.5V for a Dell). While other values can vary slightly, the output voltage is a fixed value that must match exactly. Choosing a lower or higher voltage can stop the laptop from starting up or even damage the machine and the battery.
Output amperage
Amperage is the third key parameter. Measured in amperes (A), it is usually shown directly after the output voltage (e.g. 19.5V, 4.62A). Unlike the voltage, which must be exact, the amperage must be equal to or higher than that of your original charger.
If your original charger is 19.5V and 4.62A, you can confidently buy a new charger rated at 19.5V and 6.7A, but it is strongly advised not to choose a model with a lower amperage.
Maximum power
Power is the last specification to check. It is measured in watts (W) and is often clearly highlighted on the label. Unlike voltage (a fixed value), power is a maximum capacity. A 90W adapter can deliver any power level up to 90W.
If your old charger was 65W, the new one must be at least 65W. Choosing a higher power rating (90W or 130W) will not cause any issues, because the charger will only supply as much power as your laptop actually needs.
Connector shape
Connectors come in several versions: simple round plugs and three-contact plugs (including a centre pin). Dell, like HP and Lenovo, mainly uses three-pin connectors. (Dell and HP connectors are rarely compatible with each other).
A common failure on Dell chargers occurs when the centre pin is damaged. The laptop then stops recognising the adapter: it may run on mains power, but the battery will no longer charge. This often leads users to think, wrongly, that the battery is faulty and to replace it unnecessarily.
Most Dell connectors are round, with or without a centre pin. It is crucial to check the exact dimensions (outer and inner diameters). If you do not ensure an exact match, you risk damaging your laptop’s charging port or ending up with a completely unusable part.
