Can I use a power adapter with more current but lower voltage on another laptop? [duplicate]

Here's the deal. The voltage SHOULD match (power adapters provide a steady voltage over a range of currents), whereas the current MUST meet or exceed.

If the voltage is too low, you'll get either nothing, or odd / failure behavior when the power draw on the system gets high. If the voltage is too high, you'll risk damaging the equipment you are powering.

If you have too low a current, you will either burn out the supply, trip a breaker or fuse in the supply, or the equipment will not work or fail unpredictably at high load.

If you have too high a current, the system simply won't draw as much power as the supply can provide. The supply might be a little less efficient, but no harm is done.


The current rating is the amount that's available. It's not getting forced on the device that it's connected to. For comparison, you can plug your toaster into the same outlet as you'd plug your vacuum cleaner into, but the current they draw (and can handle) is quite a bit different. (This is for comparison to the output of the adapter, ignoring the AC input side.)

I'd be more worried about the undervoltage. It may put a strain on the voltage regulator in your laptop and may also put a strain on your battery (which you might consider removing while you're using the mismatched power supply).