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Comment by mizzao | Hacker News Reader

For some reason, despite the fact that keeping a Li-I battery near full charge and in high temperatures drastically decreases its capacity over time, most laptop (and phone) manufacturers don't bother to have battery management software (to limit state of charge). I only know of Windows drivers for Sony and Lenovo.

http://superuser.com/a/664583/32370

This is probably because of some sort of planned obsolescence - they want you to replace your device.

On the other hand, in electric cars (using the same battery chemistry), where it is in the company's best interest not to replace the battery, it is charged to a maximum of 70-80%, except when soaking up extra energy going downhill, and basically maintains its full capacity for much longer.

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Well, people also complain (extremely loudly) that they paid for a 50Whr battery, and by golly, they mean to get 50Whr of power out of it! They're not going to let some slick talking corporate drone trick them into believing they should only use half of what they paid for.

Practically speaking, even assuming my battery did idle at 50% sitting on my desk, what happens when I decide to take it out to the coffee shop (or the airport!) and want it at 100%? I don't want to micromanage charging my battery and filling it up before I go out. I have enough fun discovering my car is only ever out of gas when I'm about to depart on a long drive.

So why not have it as an option so people like you who don't want to have to manage it can have it go to 100% and people like OP can stop st 80%?

> I only know of Windows drivers for Sony and Lenovo.

My Samsung has a BIOS setting to limit charging to 80%.

My Toshiba Satellite S55t-B has the Toshiba-eco utility that allows me to put it in eco-charge mode which also keeps the battery at a max-charge of 80%.

For phones, a smart charger that connects via Bluetooth to a custom app might be a realistic workaround. The charger would just need to be able to pair and to understand a simple on/off command, while the app would only need to be able to pair, configure desired maximum charge, monitor the battery level and provide some form of override GUI while the phone is charging. This feature set seems quite achievable by moderately advanced hobbyists and should even be somewhat resistant to dangerous feature-creep in case someone did a kickstarter.

This isn't so bad when the battery is removable. The idea that they are pushing for planned obsolescence is more believable when they deliberately make it difficult to replace the battery.

On the other hand, using the battery also wears it down. So it's better to stay plugged in all day at 100% and pull off the mains rather than to run off the battery and then recharge it.

My ThinkPad (T410) has the functionality built-in to the firmware (in the batteries themselves, I believe). While only Windows has GUI facilities to set them, I've been able to access the settings from the CLI in Linux as well.

Dell's battery utility allows you to set percentages when charging stops and starts.

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