# Calculating laptop power consumption [closed]

I'm trying to decide on a portable AC power station to power four laptops for at least five hours. I have the charger units for the laptops, and I'm confused on how to figure out the power consumption from them. Mainly, I don't know whether to look at the input power from the AC source or the output power going to the laptop.

Here are the specifications I see on the adapter.

INPUT: 100-240V ~ 3.2A OUPUT: 19.5V - 10.8A

So I know that the input is AC and the output is DC. And I'm looking at a 500Wh portable power station, like this one.

https://www.amazon.com/Portable-Jackery-Generator-Flashlight-Emergency/dp/B06XJ1SVPW/ref=sr_1_4?ie=UTF8&qid=1530142151&sr=8-4&keywords=500wh+portable

How do I know that 500Wh is enough to power four laptop for five hours? I know that the laptop can consume 19.5V * 10.8A = 210.6W. Or should I be using the input power, which is 110V * 3.2A = 352W?

With those numbers, there seems no way that 500Wh can power four of these laptops for five hours. But the power station claims that it can charge a laptop 7+ times, run a mini fridge 7+ hours, and power a TV and game console for hours.

My question is: Can a laptop really consume that much power under light use?

## closed as off-topic by Chris Stratton, Dmitry Grigoryev, PeterJ, MCG, Kevin ReidJul 3 '18 at 22:42

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Chris Stratton, Dmitry Grigoryev, PeterJ, MCG, Kevin Reid
If this question can be reworded to fit the rules in the help center, please edit the question.

• If the specs relevant, the one that would apply is the input. But in modern computers the actual draw would generally depend on processing load; typically the highest consumption would be while doing a lot of processing and charging a depleted battery at the same time, but it's not a given that the adapter can support both. In practical terms, this is off topic as a question about the usage of consumer electronic devices. This is a site that is reserved only for questions about design for which full engineering-level detail can be provided. – Chris Stratton Jun 27 '18 at 23:50
• Can't you just run the laptops off of battery power for 5 hours? In any event, you probably cannot be sure how much power the supplies consume unless you measure actual numbers. The numbers on the supply are maximums. So you need to get a power meter for the laptops. Check out the "kill-a-watt". – mkeith Jun 28 '18 at 1:48
• Well, the batteries on these old work laptops last for maybe 1 hour on a good day. And I don't have the option to replace them with new ones. – user3211857 Jun 28 '18 at 2:22
• Laptops can consume a ton of power under light use if their batteries are discharged. – Dmitry Grigoryev Jun 28 '18 at 10:58