Is 300w enough to charge a laptop?

Fin said:

I am looking for a power inverter to charge my MacBook on the road. Will a 300W Power Inverter do the job? I notice the 12v port says 120W max.

Will a 120W power inverter be enough to charge my computer?
Will It charge slower than a 300W?

Thanks!!

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Both will work fine and if you connect the inverter direct to 12v you can go up to 1000w...

Alternatively, most laptops have an accessory on Ebay that allows you to plug your 12v cigarette lighter plug direct to laptop, which might be a better price.

Laptops are powered by DC or direct current and so is your 12v system on your car.

Your laptop charger however runs on 110 AC or Alternating current then converts that to DC for the laptop...

So an inverter would convert 12v DC to 110 AC and then your laptop would convert 110 AC to your laptop voltage's DC again, so an inverter isn't as straightforward, unless of course you have other 110v AC stuff you want to power.

john1701a said:

USB-C PD makes life so much easier. 1 plug to rule them all !!!

It is so convenient, you can even run direct DC to DC. In other words, a powerbank can now output directly to your computer. That's much more efficient than using an inverter to convert DC to AC then AC back to DC again.

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PD is nifty technology - the device announces what voltage it needs and the supply produces it, up to 20 V at a maximum of 5 amps, or up to 100 watts of power.

But again, because it has car twelve-or-thirteenish VDC coming in, and something-else VDC going out, it isn't really more efficient than converting DC to AC and back to DC again. Why? Because it's doing that.

It can be a bit more simply built, as the AC it's using internally doesn't have to match any standardized frequency or waveform; it just has to be good enough to drive the DC output stage. But under the hood, all the pieces of "DC to AC and back to DC again" are still happening.

PriusCamper said:

The line between pure sine wave and modified sine wave has never been more blurry...

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A 'scope might unblur it pretty quick.