Can I replace 19v ac adapter with a 16v

  waratah 19:48 28 Nov 10


I have a Esystem 3086 laptop. The NEC 19v 3.42A ac adapter has broken. Can I use a IBM /Lenovo 16v 4.5 A adapter that our neighbour has lent us. the fitting from adapter to laptop fits but I do not want to cause damage?

  letsgetrdy 20:05 28 Nov 10

I've seen things damaged from using a LOWER voltage adapter before. I wouldn't really trust that it will work. Plus that one uses 4.5 amps and the other is only using 3.42. The amps are the thing that does the damage.

  letsgetrdy 20:09 28 Nov 10

Also, it's not as if you can plug it in for a few seconds to test it out. The internal damage would start happening straight away, with/without no sign of actual trouble. Then maybe a few seconds later you would smell ut-ohs. I would really avoid using it.

  Ian in Northampton 20:29 28 Nov 10

What letsgetrdy said. Don't do this. I'm more worried about the amps than the volts...

  OTT_B 20:45 28 Nov 10

waratah: The laptop, as with any electrical device, will only draw the current it requires.

Check the laptop to see what its operating voltage is (the battery is also a good indicator). If it is less than 19V (which it almost certainly is) then the laptop will contain a voltage regulator to bring the supply down to the right level.

Personally I'd try the 16 volt adaptor, but that's me.

  woodchip 21:03 28 Nov 10

and me

ps over volts would be a problem, not over amps

  peugeot man 22:00 28 Nov 10

4.5 amps is the maximum the power supply can deliver, in reality your laptop probably uses about 2.5 amps.

You can use a power supply rated at higher amps, the laptop will only draw as much current as it needs.

The important things are the voltage (a few volts lower is ok but higher is not)

Most importantly is the polarity, you must make sure that the + and - connections are the same as your original power supply.

  mooly 07:15 29 Nov 10

Laptops use "switching" type PSU's internally as well as the AC adapter. This means as the input voltage from the adapter drops the current drawn increases. If the laptop consumes (easy numbers) 100 watts internally and ran on 10v then it takes 10 amps. If the input voltage rose to 20 volts it would actually draw 5 amps... that's the way switch mode PSU's operate. So a lower voltage adapter needs to be higher rated in terms of current output... that's one thing.
Whether the laptop takes kindly to running on a lower voltage is another, the reason, internally in the PSU the currents are much higher. I suspect it would be OK in this case.

Conversely, an adapter that draws 1 amp from the mains at 240v will draw just over twice that on 110 volts... the power is the same, it's the current that varies.

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