Normally li-ion batteries lose about 0.3% capacity every 10 charges or lose capacity of about 1% a month. It's expected to lose about 30-40% capacity after 3 years. It's not as simple as that of course, that's the average over the period for expected normal use. Excessive use or light use would effect those figures.

So after owning a Switch for 3 years we may see 2hrs as the maximum running time which you could then compare to the OLED Vita runtimes bought 3 years ago at this point.

This was also pointed out when comparing the revised Vita and the early Vita where you are comparing new batteries to heavily used batteries which isn't a level playing field.

That is assuming it is used in handheld mode and charged once a day, and I presume you are talking about charging it from 0% to 100% (which because of heat production is not good on the molecular structure of the battery, it is better to charge it in increments.) I am a pretty avid handheld gamer, and don't even charge my 3DS and Vita that much. If I could play these docked (in fact in the Vita's case I also have a PSTV), I'd save even more charges, as I'd more often use direct power. 

I probably charge my 3DS four times a week, and after almost four years of owning it, any change in battery life is imperceivable to me. What helps a lot is Nintendo's ability to retain almost all of the charge when the system is in sleep mode. It can last days in sleep mode. I expect the same for the Switch. 

I'm sorry, did Nintendo say "when you turn your wi-fi off" or "when you set to lowest brightness"? No, they didn't!

Come again.

You're seriously still in denial over the system's portability? That's the real story here.

And another test showed its 3hr 2min with Wifi on and 75% brighness (default setting)

"Playing Zelda single player. Low battery warning came at 2h39m.

http://www.siliconera.com/2017/02/23/testing-nintendo-switchs-battery-life/

Your next portable folks! ;p" (Nem)

WTF are you even talking about? I'm sorry, did Nintendo say "Low battery warning came at 2h39m"? No, they didn't! They said that the battery life is about 3 hours for Breath of the Wild.

Now you should come again.

So what? People compare this to the 3DS wich is 3 to 5 hours and try to strech it.

Switch is 2.5 to 3h from what we know. It's miserable. Theres no sweetening this.

And dont come with "oh if we play this indie game or leave it in sleep mode it lasts longer". Just admit it, this battery life is terrible. Because no fan supporting can ever change that.

But, this comes from the same group that thought this system would be out last year. /shrugs

3DS is 3h-5h but is closer to 3h when playing games like Smash or Pokemon Sun/Moon, Switch is 3 hours with Zelda, which means medium and low intensive games can probably last 4 and 5 hours, some indies maybe even more.

I mean, how partial can one be? You are comparing 3DS with full brightness and online functionality to Switch, low brightness, no online online or playing an 8/16 bit style game. 

Do you guys see yourselves? Because it's quite honestly worthless to spend time debating this.

Switch battery life is terrible. If you are good with 2 hours to 2.5 hours, good for you. But this surely isn't what one expects of a portable (wich is fine really because this is a home console afterall). 

But, i don't have to say this. Reality will eventually sink in.

The way you keep making the number lower for no reason kind of tells me how much you are you forcing yourself to believe your own words. Vita hasgames that lasts 2h-2.5h, but nobody questions that, 3DS has games that make the battery go to 3 h, you don't question that, but when Switch is showing you 3 hours in a super demanding game, you say is shitty with no question, ok.