Cann I use a 19.5V 4.62A laptop charger for 19V 4.74A laptop?

Question

My laptop charger (Toshiba Satellite L850 18U - 19V 4.74A) has been broken. So I bought a new charger - Trust 90W charger. According to the new charger's packaging it is suitable for my laptop. But when I opened it on the product label it says that the charger is 19.5V 4.62A. Do you think that it is save to use it? As the packaging says that it is suitable for 19V 4.74A.

Answer 1

To be absolutely safe:

• No, you shouldn't use chargers with different voltages at all and if you do, you will most likely void the warranty of either the laptop, the charger, or both. That also goes for the safety guidelines so if anything exploded in your face, YOU would be responsible. (Except maybe the charger manufacturer could be if they officially stated it's compatible with your model)

If you don't care about warranty and are ready to be responsible for your safety:

1. Voltage: 19.5V and 19V is a relatively small voltage difference. It is most probably safe to use as long as:

• The current of the charger is the same or higher than that of the laptop. (Which in this case is not, but then again, 4.74A and 4.62A is a relatively small difference) To explain a bit more:

  • The output power (Amps * Volts) of the original and the new charger differs in 0.6 Watts, the 19.5V charger having more output power. That's negligible.
  • Laptops usually don't draw the full power from the charger even when in use and being charged at the same time. The original charger was ready to output slightly more power than needed so even then - only, let's say, 4A were drawn. Which is well enough for the new charger to handle. Though in case you were to do heavy computing (gaming, rendering 3D or videos, or similar), and charging the laptop at the same time, it might need to draw the full power, in which case the charger wouldn't supply enough for it's rating and start to get very or extremely hot and your laptop would start to slowly discharge even when connected. In that case, you should immediately stop doing what you were doing and disconnect the charger.
  • Most chargers from trustworthy companies have a fuse that would shut the charger down in case of extreme overheat (as in extreme power draw), but you don't want to risk anything.

2. Current: As explained above, the current rating of the charger should be same or higher higher than that of the laptop. (To understand - Laptops draw current from the charger as needed. Chargers don't push current inside laptops. So if the laptop is fully charged, it takes ~0A from the charger even when connected.)

3. Size: The charger's connector needs to be exactly the same size as the old one (meaning that it needs to fit the laptop connector), otherwise it might either not fit at all, or if it does, you might break the laptop's inside connector and make it unusable even by original chargers.

4. Polarity: The polarity of the charger connector and the laptop connector (or the original charger connector) must be the same. It most probably is, the industry standard is "+" on the inside pin and "-" on the outside. But to be sure, check for polarity on both the charger and the laptop. There should be a picture similar to this - polarity image