Instructables

What difference does amperage make in a notebook charger?

While shopping for a new notebook charger for my son's computer I discovered that the new replacement charger produces 19 volts and 3.95 amps. The original charger is 19 volts and 2.65 amps. Should I be cautious of the new charger?

This current rating is a statement about the maximum amount of current the charger could supply, if the load desired it. 

That is to say the character of the load determines how much current will flow.  For example,when nothing (a so called open circuit) is connected to the charger, the amount of current that flows out of the charger is zero amperes.

The new charger (rated at 19V, 3.95 A) will work just as well as the old one (rated at 19V, 2.65A).  Presumably for both of these, the actual number of amperes the laptop draws while charging, or running, or whatever,  is a number less than 2.65A, and thus less than 3.95 A too.



Bear in mind its not "a charger", its a power supply, the "charging" is done inside the computer, by its own electronics. The computer will draw what it needs - upt ot the original couple of amps probably, it's internally limited.

Steve
Re-design2 years ago
Was the charger listed as a replacement for the lost charger?  If so then it will be okay.

If not then you need to find out something.

If the current limiting circuit is in the broken charger then you may damage the battery by overcharging it.  A battery is one of the few things that will accept much more current than it is capable of handling and will turn the extra into heat.  After a few cycles of overcharging the battery will be damaged.

If the current limiting circuit is in the computer then there should be no problem.
jrh0652 years ago
As I understand it will just take longer to charge the laptop. It shouldn't cause any problems.
A charger that can offer more amperage is not going to affect the charge time.
Oh, read it wrong and thought the new one had fewer.
If the new one had fewer amps there would be a chance that the notebook wouldn't power up at all or could blow the charger.
verence2 years ago
If it is a power supply for the laptop (the battery stays in the laptop and is charged there), there is no need to worry. The laptop will consume what it needs and the extra amperage will just not be used.

If it is an external charger (the battery is taken out of the laptop and plugged into the charger) and the charging control logic is inside the charger and not the battery, make sure, the charger was built for your type of battery.
Burf2 years ago
There should be no problem with the new charger. The 3.95 amps are only indicative of the charger's potential, the notebook will only draw the amount of amperage it requires from the charger.