Replacing a laptop battery or a laptop charger fails for one boring reason: people buy by brand and model name, while the part is specified by numbers. A 19V adapter on a 20V laptop will not charge it, and a 4,0×1,7 mm plug does not fit a 5,5×2,5 mm socket, no matter what the listing says. The Laptop Parts collection holds 12.452 active references. Here are 18 of them with live stock and verified prices, sorted so you can see where the money goes.

Three numbers decide compatibility

Voltage must match. Read the label on your old adapter: it says something like 19V, 19.5V or 20V. A one-volt difference is usually tolerated; three volts is not.

The connector is physical. 4,0×1,7 mm, 5,5×2,5 mm, 7,4×5,0 mm — these appear in the product names because they are the specification. Measure the outer and inner diameter of your plug, not the brand.

Wattage is the ceiling. Volts × amps equals watts. Under-powering a laptop makes it throttle; over-powering is safe because the laptop draws what it needs.

Batteries: what mAh and Wh really tell you

Prices and stock read from the catalogue on publication date.

Watt-hours are the only honest comparison, and they are not always printed. Two examples from the table: the Dell 46 Wh pack at 36,99 € works out to 0,80 €/Wh, while the Dell E7440 34 Wh pack at 41,99 € lands at 1,23 €/Wh — more expensive per unit of energy despite costing less per part. The Mitsu 33 Wh at 22,99 € is the best ratio here at 0,70 €/Wh.

When a listing gives volts and mAh instead, multiply: 7,6 V × 4,1 Ah = 31,2 Wh, so the Lenovo L16C2PB2 at 31,99 € comes out at 1,03 €/Wh. Same arithmetic, different label.

Chargers: cost per watt is where the money hides

Prices and stock read from the catalogue on publication date.

Do the division and the market becomes legible. A 65 W adapter at 11,99 € is 0,18 €/W. The Mitsu 90 W at 21,99 € is 0,24 €/W. The USB-C 100 W unit at 23,99 € is also 0,24 €/W — and it is the only one in the table that can charge a phone, a tablet and a laptop from the same brick.

GaN units cost roughly three times more per watt: the 65 W Urban Factory at 43,99 € is 0,68 €/W, and the 67 W Native Union at 49,99 € is 0,75 €/W. That premium buys size, not power. If the adapter stays on a desk, it is money you do not need to spend.

Browse all 12.452 laptop parts in stock

How to read the label on your old adapter

• Output line: volts and amps. Multiply them to get watts.
• Connector: outer × inner diameter in millimetres, measured with a ruler or caliper.
• Polarity: centre-positive is standard on laptops; check the symbol anyway.
• Model of the laptop, not of the adapter, is what you search for.

Before you order

1. Write down volts, amps and connector size from the old part.
2. Compare those three against the product name — they are always listed there.
3. Check stock: several references have only 1–4 units.
4. For batteries, compare watt-hours, not just price.
5. Keep the old part until the new one charges and reports a full percentage.

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Frequently asked questions

Can I use a 90 W charger on a 65 W laptop?

Yes, provided voltage and connector match. The laptop draws only what it needs, so a higher wattage is a ceiling, not a push. The reverse — a 65 W adapter on a 90 W laptop — causes throttling or slow charging.

Do I need the exact OEM battery reference?

You need the same voltage and a compatible form factor. Compatible packs in this catalogue start at 20,99 € (HP JC04) against 92,99 € for an Apple A2442 pack, so the reference on the label is what you search, and the price depends on how proprietary the shape is.

Why is a GaN charger three times dearer per watt?

Because you are paying for size. A 65 W GaN brick at 43,99 € measures 0,68 €/W against 0,18 €/W for a conventional 65 W unit at 11,99 €. Same power, far less volume.

Is a universal USB-C charger enough?

Only if your laptop charges over USB-C. The multivoltage 5–20 V 100 W unit at 23,99 € covers USB-C Power Delivery laptops; older barrel-plug machines still need their 19–20 V adapter with the right connector.

What is the best value in this catalogue right now?

By cost per watt, the 65 W adapters at 11,99 € (0,18 €/W). By cost per watt-hour, the Mitsu 33 Wh battery at 22,99 € (0,70 €/Wh).

Find your battery or charger