It's a model issue. As to 40 WHR that's an odd way to go about it since a gamer laptop would need many times that to get through a day. There's up to a 10X difference in battery times depending on use.
I can't guess what the goal here is but let's say you want 8 hours. OK, we look for that then double it since the batteries degrade with use. To avoid dropping out in just a few months we building in about double the hours when new.
My buddy carries one of those car adapters for long times away from AC power.
Seems that as of late most Laptop Manufacturers only offer a small battery for their Laptops (40 WHR) they once offered 95WHR as an option when buying or looking to buy a larger battery for a laptop. I am wondering what brands offer a larger Battery that will extend the use of a Laptop when on Battery? Does any still do?
And secondly why are not laptop batteries not more interchangeable seems each one has something different and you have to be very specific as to what battery you might buy that will actually work with a Laptop. Like HP each different model has a totally different shaped battery and so you cannot use one with a new laptop even though the battery might be still good. That is another issue with manufacturers today just to sell more parts / batteries they make so many different ones and now they are commonly only 40 WHR which don't last???
Looking at a possible Dell as a new laptop but with limit batteries I am now wondering what is available as to larger Batteries? before I start looking at Laptops being I do a lot when on battery only and no ac power to plug in.
Any suggestions will be welcome as to brands and what battery is available?