The power adapter is a vital, yet often underestimated, component of laptops. Its presence is usually only noticed when it fails, forcing you to urgently look for a replacement.
Given how tricky the choice can be, this guide aims to bring together the key information about HP’s specific requirements. The following sections focus on the different types of chargers designed for HP laptops.
Why you need to be careful when buying a new adapter
It’s common to end up needing an alternative power source in a hurry, for example after forgetting your charger at home. You then try to use any adapter whose plug seems to fit. If the machine powers on, you assume everything is fine. However, that is not always the case.
Using a charger whose specifications do not match your laptop’s requirements can cause problems. Here are the different possible outcomes when there is an incompatibility:
- The adapter you chose is correct, no issue.
- The voltage is correct, but the current is higher: this will work perfectly, because the laptop regulates how much power it draws.
- The voltage is correct, but the current is too low: the laptop will run, but the charger may overheat and the battery will not charge.
- The voltage is too high and the current is correct: the device may shut down or start up, but the charger will heat up dangerously. There is a risk of blowing the protection fuse or, in the worst case, damaging the laptop’s motherboard.
- The voltage is too low and the current is correct: the laptop may not power on, although the likelihood of causing damage is low.
What to check on an HP adapter
Several technical factors must be considered to correctly choose a new power adapter for an HP laptop.
Input voltage (INPUT)
This is the AC power that the adapter draws from the mains. This value is between 110V and 240V. Standards vary from one region of the world to another. Most adapters are designed for a 100V to 240V range. This allows users to travel without having to buy a new charger, as long as they have a physical plug adapter for the wall socket. The value is shown on the charger label next to the wording (INPUT).
Output voltage (V)
It is essential that the voltage of the new adapter is identical to that of the original.
- If the voltage is higher, the laptop may refuse to start, and there remains a small risk of damaging the circuitry.
- If the voltage is lower, the machine will probably power on, but it will not receive the power it needs. This can cause a range of issues, from sudden shutdowns to erratic behaviour.
Lower voltages are generally safe for the laptop, but can shorten the life of the adapter. The output voltage is shown on the charger label after the wording (OUTPUT).
Output current (A)
The current, measured in amps, is the third key rating and is usually listed after the voltage.
- A higher current rating than required is better, as the adapter will operate with more headroom and be less likely to overheat.
- On the other hand, if the current rating is lower, the charger will overheat and may fail. In addition, the laptop may run without the battery being able to recharge.
Power (W)
The power in watts is often printed on the label. It must be equal to or higher than that of the original adapter. A lower power rating is strongly discouraged. For example, a 90W adapter can safely replace a 45W adapter, as long as the voltage is the same.
Connector type
HP laptops generally use plugs with three contacts (one positive +, one for ground and a third for data). Although they may look similar to Dell plugs, they are rarely interchangeable. The laptop may fail to recognise an adapter from a different brand, which would prevent the battery from charging.
The most common HP plug sizes are:
- Outer diameter – 4.0 mm, Inner diameter – 1.7 mm
- Outer diameter – 4.5 mm, Inner diameter – 3.0 mm
- Outer diameter – 4.8 mm, Inner diameter – 1.7 mm
- Outer diameter – 5.5 mm, Inner diameter – 2.5 mm
- Outer diameter – 7.4 mm, Inner diameter – 5.0 mm
- Type-C
Where to find your model’s specifications
The best way to make sure of compatibility is to compare the new adapter with the old one. If the original is missing, you can find the information:
- On the label on the underside of the laptop.
- On the battery (not always available).
To know the exact plug diameter, you can inspect the laptop’s power jack or search online using your model reference.
Faults and warning signs of a failing adapter
What are the warning signs, and how do you identify whether the charger is at fault?
1. The charger is plugged in, but the laptop does not respond
The main causes are:
- The adapter is faulty.
- The cable is cut or damaged.
- Another power problem that is not related to the charger.
- Using an incompatible adapter.
If none of the laptop’s indicator lights come on, the fault is very likely related to the charger or the cable.
2. The laptop runs on mains power, but the battery does not charge
Common reasons are:
- The battery itself is faulty.
- The third pin (data pin) of the charger plug is damaged.
- Using a non-compliant adapter.
To identify the source of the problem, it is recommended to test the laptop with another charger or test the battery in another laptop.
3. The adapter works, but makes a loud buzzing noise
You can continue to use it with caution. However, it is advisable not to leave the adapter plugged in unattended. This noise is a strong indication that it is about to fail.
4. The charger gets very hot
It is normal for an adapter to feel warm. However, if it gets so hot that you cannot comfortably keep your hand on the case, you must contact a specialist or plan to replace it.
5. The laptop shuts down or restarts when it is moved
The most common cause is a power jack damaged on the laptop side.
6. The laptop suddenly shuts down for no apparent reason while on mains power
This problem is usually caused by a power jack damaged on the laptop side.
