Chapman: Unlocking my Lenovo laptop [LWN.net]

In a lengthy blog series (part 1, part 2, and part 3), Matthew Chapman described the process of getting a non-Lenovo battery to charge in his Thinkpad laptop. He reverse-engineered the authorization that real batteries do and changed the code in the embedded controller (EC) on the laptop to allow other batteries to charge. "I look in BIOS to see where these messages are coming from. Both this message and the original unauthorised battery message are displayed by LenovoVideoInitDxe.efi: don’t ask me why this code is in this module rather than somewhere more relevant (may I suggest LenovoAnnoyingBatteryMessageDxe.efi?), but it might have been convenient to put it in the video initialisation module as the message is displayed when the screen is cleared post-POST [Power-on self-test]." (Thanks to Neil Brown.)

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Capacity over longevity

Posted Feb 13, 2016 22:56 UTC (Sat) by marcH (subscriber, #57642) [Link] (17 responses)

The main issue is of course why isn't there any user interface option to cap the charge at 90% capacity instead of 100% and have it last 5 or 10 years instead of barely 2.

Example showing how simple and easy such a "user interface" can be:
http://www.plugincars.com/tesla-roadster-battery-life-stu...
"Standard mode in the Roadster protects the battery by only allowing charging up to 90 percent; range mode uses the whole pack. In range mode, the Roadster should be capable of 244-mile runs, but longevity will be sacrificed."

This option is missed real bad for the very many laptops docked most of their time.

Here's the next challenge: hack whatever firmware is required to implement this switch.

No doubt manufacturers are happy with planned obsolescence but consumers are guilty too since they only look at the maximum capacity and charge speed (another battery killer) and never even think about the longevity.

Maybe the growing market share of electric cars will indirectly educate consumers about longevity. Throw-away smartphones are marketable, cars less so.

http://batteryuniversity.com/learn/article/how_to_prolong...

Capacity over longevity

Posted Feb 14, 2016 3:20 UTC (Sun) by rsidd (subscriber, #2582) [Link] (3 responses)

That's a fascinating thought. Is there any way to prevent a laptop battery charging in software? Or else, can the battery app pop up alerts saying "Your battery is 90% charged, unplug now for greater life"? That would help. But as for phones, it's not just the batteries (which are replaceable in most cases, even if not as easily as they used to be) -- the entire unit seems to develop problems within 2 years.

Capacity over longevity

Posted Feb 15, 2016 11:43 UTC (Mon) by jezuch (subscriber, #52988) [Link] (2 responses)

> Or else, can the battery app pop up alerts saying "Your battery is 90% charged, unplug now for greater life"?

Better, I think, would be for the software to lie. I.e. show "100%" when it's actually at 90%, and stop charging then. I know that we in the Free Software community like having more options where they are possible, and to use our hardware to its fullest potential, but it's an unnecessary decision forced on the user :) (SSDs already do something like that with over-provisioning of the flash array.) Well, you could offer an option to charge to "111%", if one really, really, really needs some extra battery time, but with a stern warning that it will harm the battery.

Capacity over longevity

Posted Feb 15, 2016 13:15 UTC (Mon) by nye (guest, #51576) [Link] (1 responses)

>I.e. show "100%" when it's actually at 90%, and stop charging then.

I believe Android does this by default, but at one point (possibly still the case) it didn't adjust the entire curve to compensate, which led to phones seemingly dropping several percent almost as soon as they were unplugged, with the result being the inevitable incendiary nerdrage about how UTTERLY UNACCEPTABLE this is, and how the people who make these phones are the worst developers imaginable, literally Hitler, etc.

Capacity over longevity

Posted Feb 16, 2016 1:01 UTC (Tue) by hitmark (guest, #34609) [Link]

More like brogrammer/troll rage, enjoying that they got something to flame about rather than understand the underlying actions.

Capacity over longevity

Posted Feb 14, 2016 4:11 UTC (Sun) by Fowl (subscriber, #65667) [Link] (1 responses)

Dell has exactly this. Accessible from their firmware UI even.

A google image search for "dell power manager" will return their many, many attempts at a Windows GUI.

Capacity over longevity

Posted Feb 15, 2016 15:54 UTC (Mon) by rvfh (guest, #31018) [Link]

My Lenovo has an option to, to charge up to 60% :-(

Capacity over longevity

Posted Feb 14, 2016 8:23 UTC (Sun) by njs (subscriber, #40338) [Link] (3 responses)

Thinkpad firmware has actually provided this option for many many years, and getting kernel support has also been straightforward and well-documented for many many years:

http://www.thinkwiki.org/wiki/Tp_smapi#Battery_charge_con...
http://www.thinkwiki.org/wiki/Tpacpi-bat

For some reason though there aren't any decent UIs that expose these options (that I know of).

tp_smapi UI

Posted Feb 14, 2016 14:33 UTC (Sun) by jmayer (guest, #595) [Link] (1 responses)

The reason may be that this module is not part of the standard kernel. IIRC it never made it in because the legimitatcy of the source could not be ascertained (no legal entity to do a s-o-b).

tp_smapi UI

Posted Feb 15, 2016 8:28 UTC (Mon) by pbonzini (subscriber, #60935) [Link]

I think that doesn't apply to tpacpi-bat, though.

Capacity over longevity

Posted Feb 16, 2016 0:43 UTC (Tue) by marcH (subscriber, #57642) [Link]

Many thanks to everyone who answered. It pushed me to do some research and I found this level of control implemented in this Windows-based tool which I didn't get installed by default:
http://support.lenovo.com/us/en/downloads/ds014924

The feature is of course hidden behind some "Advanced" button and then buried among a gazillion of other fine-tuning knobs that would make any Apple fanboy laugh to tears for a couple generations. But hey it's there and I just started using it; so thanks again. Even more so considering my battery is not end-user replaceable. I wish I had known sooner.

Capacity over longevity

Posted Feb 14, 2016 9:00 UTC (Sun) by zdzichu (subscriber, #17118) [Link]

> The main issue is of course why isn't there any user interface option to cap the charge at 90% capacity instead of 100%

But there is such interface: http://www.thinkwiki.org/wiki/Tp_smapi#Battery_charge_con...

Capacity over longevity

Posted Feb 15, 2016 15:55 UTC (Mon) by rvfh (guest, #31018) [Link] (2 responses)

Nissan LEAFs have the option in the charge programmer to either charge 100% or 80%.

Capacity over longevity

Posted Feb 15, 2016 16:19 UTC (Mon) by JanC_ (guest, #34940) [Link] (1 responses)

Seeing values of 60%, 80% and 90% in this thread, it seems like those values are chosen quite arbitrarily?

Capacity over longevity

Posted Feb 15, 2016 16:54 UTC (Mon) by marcH (subscriber, #57642) [Link]

According to this link: http://batteryuniversity.com/learn/article/how_to_prolong...

... some manufacturers can decide that 100% = 4.2V while others more concerned about longevity can decide that 100% = 4.1V. In other words 100% is arbitrary in the first place.

From a user friendliness perspective having two modes ("longevity" vs "capacity") is more than enough. Simplicity could also increase the chances of this feature being actually implemented and distributed. How would the average, non-chemist user know the difference between capping at 83% versus 86%?

Capacity over longevity

Posted Feb 17, 2016 0:44 UTC (Wed) by rahvin (guest, #16953) [Link] (2 responses)

Having bought a Lenovo laptop last year I can say this. They install a custom application on the laptop that strongly encourages you to enable a battery saving feature that keeps the battery charged at 60%. They are the only manufacturer I've seen do this.

Capacity over longevity

Posted Feb 18, 2016 22:12 UTC (Thu) by ttonino (guest, #4073) [Link] (1 responses)

Sony and Toshiba also offer this. Also Dell, it seems.

But 'strongly encourage'? No, have to dig up the settings.

Capacity over longevity

Posted Feb 19, 2016 2:27 UTC (Fri) by rahvin (guest, #16953) [Link]

After using the laptop for about an hour running on the cord the Lenovo software popped up essentially a full screen warning and recommendation to switch modes and all it required was a single click on a yes button to enable it.

Yea switching it back and forth is buried in an advanced settings menu but bringing up a popup with lots of scary language about battery life and warranty about an hour after being on mains power is pretty much right out in your face.