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girishso

1. It’s ok to keep laptop plugged in, even at 100% battery

2. Keep temperature as low as possible, maintain airflow

3. Avoid fast chargers

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>1. It’s ok to keep laptop plugged in, even at 100% battery

It might be "ok" to keep it plugged in at 100%, but if your laptop has a "battery conservation" mode that limits the charge to 80% (or similar), that's even better.

If you're on a Mac, you can install the free version of AlDente:

https://github.com/AppHouseKitchen/AlDente-Charge-Limiter

I keep my MBA at 60% since it basically never goes for more than a couple hours within being plugged in.

Also batfi - https://github.com/rurza/BatFi

Oh wow, looks like that's brand-new (from March?) as opposed to AlDente which is about 4.5 years old at this point, at least according to GitHub releases.

It looks really really sharp, the UX is definitely much more visually appealing than AlDente. I might have to check it out.

I think (though I might be wrong) charging of Apple hardware detects usage patterns and it would already not charge the battery to 100% if you’re frequently plugged in.

Kind of, it's described here [1].

But that only applies if you have a "charging routine", e.g. you always charge overnight and use it on battery all day long starting at 9:15 am:

"When the feature is enabled, your Mac will delay charging past 80% in certain situations. Your Mac learns your charging routine and aims to ensure that your Mac is fully charged when unplugged."

But in my experience, the feature doesn't do anything if your Mac is just usually plugged in. It simply stays at 100% because there's no routine for it to learn for when you tend to unplug it.

[1] https://support.apple.com/en-us/102338

Useful info, thanks. There’s really no reason for my MBP to be charged 100% - I rarely unplug it

I wish more devices offered a way to enable a “slow charge” mode.

When I’m plugging my laptop into my dock to work for the next 8 hours it doesn’t need fast charging.

When I’m plugging my phone in before bed to charge for the next 8 hours it doesn’t need fast charging.

i have 2 chargers near my bed, one has 3 amps, the other one has 1. i use one on another depending on how fast i need it charged. not the best solution, but it works.

I have a wireless charging cradle on my nightstand intentionally hooked to a slow charger. It works fine most of the time except on the rare occasion when the phone charge is low and I'm going somewhere in a couple of hours. It would be great if there was a charging cradle with a simple "fast/slow" charge switch.

Or even better, if phones had a built-in charge status UI that instead of just saying "NN% charged / TT minutes until full" had a slider controlling charge speed that showed a range of "time until full". That way users could intelligently choose the charge speed vs time based on context.

At least on Android it's possible to disable fast charging. It's in the battery settings on my phone.

> When I’m plugging my phone in before bed to charge for the next 8 hours it doesn’t need fast charging.

iPhones do this with "Optimised Battery Charging" turned on (which I believe is the default setting) - "allow iPhone to wait to finish charging past 80% until the time you need to use it" (which it learns over time.)

Android has something similar. A notification pops up when I plug in at night, letting me know that it's charging slowly because I usually leave it plugged in overnight, and that I can disable it (once or permanently) to switch to fast charging.

On my laptop I have a script to set

    /sys/class/power_supply/BAT0/charge_control_end_threshold

I could imagine automating this to set the threshold to the current battery level, and incrementing the threshold by 1% every N minutes to control charge speed.

Right now I try to keep it at 50% max charge like this while plugged in at home.

As others have mentioned, many phones do this in software, but I find the easiest solution is simply to use a charger incapable of fast charging.

It's harder to do with a usb-c charger and laptop because the spec requires higher voltages are made available with higher wattages, and manufacturers only make products to hit sweet spots in the specs and market.

You might end up with a readily available 65W charger to get the necessary 20V, even if you don't want 3A.

https://en.wikipedia.org/wiki/USB_hardware#USB_Power_Deliver...

> 3. Avoid fast chargers

Isn't this primarily due to heat produced? Aka cool fast charging is better than warm slow charging.

I seem to remember a tweet I think by Mishaal Rahman (or another android journalist) on this.

Yes that's absolutely the case. So it just depends on how good the cooling system is. For a phone, it has no active cooling system. For an electric vehicle, almost all manufacturers (except Nissan Leaf) have adopted active cooling and you can expect them to do a good job activating adequate cooling for the battery.

In absolute terms, cooler isn't always better.

For example, Tesla has a pre-heat function for their cars' batteries that can be used prior to charging.

https://www.tesla.com/ownersmanual/model3/en_us/GUID-F907200...

That affects charging speed, not battery longevity.

It can affect battery longevity. If you charge lithium ion at cold enough temperatures, you get lithium plating which rapidly degrades capacity and can lead to internal shorts and fires.

It's due to heat produced, gas generated from overvolting the battery, and stress gradients from different levels of charge across the battery.

I disagree with your point #2 as it is written. You want to keep you battery close to the temperature at which it is rated. Cycling below that also harms batteries and shortens their life. If you really want to geek out about that, I can recommend for example a talk [1] that was given last week (you can jump to slide 15). The presentation has nice electron microscopy images of the cracking this type of abuse causes in batteries.

[1] https://academy.covalentmetrology.com/wp-content/uploads/Bat...

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