Minimum required watt for for new AC adapter

[screennamesaver]

I want to get a second power supply for my Victus laptop.

The 15-20v, 6a and 90w AC adapter i bought triggers a warning notification ones plugged in. "Incompatible Power Source Detected" and then it stops charging and goes to battery. 

The OEM adapter is 200w. 

What are the minimum requirements for an AC adapter? Watt, voltage and ampere? 

Or is there a work around to the error message? Can I change some settings or update something?

[banhien]

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@screennamesaver wrote:

The OEM adapter is 200w. 

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@screennamesaver 

All you need is a 200W AC Adapter or higher. There are 230V 200W and 110V 200W the original adapter supports 110V to 230V.

Regards.

[screennamesaver]

Hello @Banhien

So is 200w the minimum requirement or can I use a 150w adapter? Or maybe one with even lower voltage?

I ask since there is quite the price difference between a 200w and a 150w adapter.