They don’t (normally) just fail, but they’ll see a reduction in lifetime over time.

IIRC, one normally sees a number of full cycles before the lifetime is down to some level, think 80% might be it, and that’s what’s considered “lifetime”.

googles

Yeah, or at least that’s the metric that Asus is using here:

https://www.asus.com/support/article/604/

The life of a Li-ion battery is approximately between 300-500 cycles. Under normal usage conditions and in ambient temperatures (25℃), the Li-ion battery is expected to discharge and recharge normally for 300 cycles (or about one year). Afterwards the battery capacity will drop to 80% of its initial capacity.

That being said, I believe that those are full cycles, from 0 to 100% to 0. I don’t normally fully cycle a laptop battery; I don’t take it down to 0. And a tactic that a number of devices use to trade battery capacity is not fully-charging the battery; that sacrifices near-term battery capacity to reduce the rate at which the battery degrades, as topping it off produces a disproportionate amount of that degradation. Your laptop’s BIOS or OS (for when the laptop is charging while running) may have a way to pull that off.

And there are gonna be some other factors; high temperatures also accelerates the rate.

You can replace laptop batteries on laptops that I’ve looked at, though these days they aren’t normally designed to be user-replaceable.

You can mitigate this by getting a USB-C PD power station, which I suspect is what laptop vendors expect users to typically do. That has the advantage of being simple and portable across laptops, and (as some laptops with two internal batteries used to be able to do) lets one effectively have an infinite supply of juice, as one can leave the laptop running on the internal battery while swapping in another powerstation, but also has some disadvantages:

• There’s no protocol for letting the laptop automatically flip the thing on after it’s plugged in, so you have to keep an eye on the laptop, wait to be notified of low internal battery, then plug the thing. You can’t plug in a 100Wh powerstation and just get an extra 100Wh; you have to manually let the laptop drain, then be warned, then plug in the powerstation and charge the laptop.

• I don’t believe that there’s a USB device class for a “battery”, or at least it hasn’t been implemented on anything that I’ve ever seen, so the computer cannot know what the remaining capacity in the power station is. This means that the computer cannot compute a rate of powerstation drain and remaining time, which drives me nuts. There are protocols and software for UPSes to report remaining battery (permitting a desktop system to shut itself down cleanly rather than going down uncleanly when power is exhausted) but I’m not aware of any powerstation vendors that implement one of these protocols.

• More-obnoxious to carry. I don’t care about a bit more weight, but another cable and box is annoying.

Frankly, what irks me is how hard it is to get a laptop with a 100 watt-hour internal battery (the most one can legally fly with in the US internal to a device) in 2024. I understand a laptop vendor selling a reduced-size battery, but it used to be common for it to be possible to get a more-expensive, larger-capacity battery. Very few laptop vendors today sell laptops with 100 watt-hour batteries, and those are typically aimed at people who want very-high-power-usage laptops and to try to squeeze a bit more life out of the things. I specifically looked at the Framework laptops and was surprised by the fact that they don’t have the option for a larger internal battery, as it seems like a no-brainer for their target audience. I mean, yes, it shaves down the price on the laptop (which I don’t care about when it comes to just shoving more battery in) as well as weight (which I also don’t care about). I’m really amazed that more people aren’t asking for larger batteries.

I liked what the old (thicker than current) Thinkpads used to do. One could get a big chunky battery that would extend beyond the back of the laptop, adding weight, size, and cost, but also battery capacity. And it was trivial to replace, just slide externally-accessible release sliders and slip it out.

There’s so much you can do if you have a larger battery available to work with:

• Brighter screens.

• Larger screens.

• Beefier speakers.

• More compute power.

• Just being able to run longer.

• Use the “don’t charge above some fixed percent” tactic to reduce battery degradation, have the battery last longer.

• Add more power-using hardware to the device. GPS receiver? Microphone array? Sure, why not, if you’ve got the power to run them?

Just drives me nuts.

It depends on a number of things. Heat kills lithium batteries fairly quickly. A battery will last much longer in a laptop with good cooling. Storing the battery at full charge is not good for it. Some laptops let you specify a maximum charge percentage. Only charging to 80% will make it last much longer. Charging to 40-50% if you know it’s going to be plugged in for an extended period of time a good idea too. Fully discharging the battery is a lot worse for it that only discharging to 20%.

If you are not fully cycling the battery daily, you should be able to get 4-5 years if you treat it well.

The Framework laptops are some of the easiest laptops to replace the internal battery on and you can buy replacements directly from them.

Most internal batteries can be replaced provided that you can actually buy a replacement. Some laptops have glue or double sided tape holding the battery in place and prying a lithium pouch cell out is not the safest thing to do.

Mine is from 2017 and is still fine, not perfect but fine. has 700+ cycles and moderate to high usage. Most battery’s can be replace quite simple pop the back cover of and disconnect it, except for tablets and some 2 in 1s they are glued together. Or you have to remove the Screen to get into it. good luck keeping the screen in 1 piece there.

Doesn’t it depend on manufacturer?

For most laptop’s batteries can last up to 5 years, if lucky up to 8 years like on of my older laptops.

In older laptop models batteries are very easy to remove and replace, in most cases you just take out the battery from the back.

With never laptops in most cases you need to remove the whole bottom cover and then you get access to the battery that is still pretty easy to remove. You just pull one wire and unscrew a couple of screws and you can just swap the battery.