Many people keep their laptops plugged in and charging when using them at home, and rarely if ever take them out of the home. This keeps the Lithium battery at 100% State Of Charge (SOC), which I understand shortens the battery life. It would seem to follow that the battery life could be optimised if there were some way of selecting "storage charge" on the laptop, whereupon the charging circuit would keep the battery at 50% SOC. This issue has become more pressing now that manufacturers have switched from removable Li-Ion battery packs to built-in LiPo battery packs. I'm guessing that all the necessary hardware is already present, and so this would be a relatively simple software fix. Is this an issue that has already been addressed and for which a solution is already available?


closed as off-topic by winny, Leon Heller, laptop2d, Lior Bilia, pipe Nov 11 '17 at 19:20

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  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – winny, Leon Heller, laptop2d, Lior Bilia, pipe
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  • 2
    \$\begingroup\$ My Thinkpad comes with this as user settsble to maximize battery lifetime. However, this is off-topic for this forum. \$\endgroup\$ – winny Nov 9 '17 at 13:19
  • \$\begingroup\$ Apologies for posting an off-topic question, and thanks for letting me know that at least some laptops are equipped with this facility. I will pursue this in a more appropriate forum. \$\endgroup\$ – Andy Kay Nov 9 '17 at 15:46

...whereupon the charging circuit would keep the battery at 50%

You are right that it can be implemented/solved with software, my Dell for example has an option for "mainly AC use" which is in the (BIOS/UEFI) setup. This software is at a quite "low level" as it has to work directly with the hardware (the charge controller) therefore it is (or needs) a setting in BIOS, UEFI whatever you call it.

This also means that if there is no support for this build into the laptop firmware (a function to stop the charging) then there can be no (Windows/Linux) software to control this either as that would need that function.

So it really depends on the cooperation of the hardware manufacturer. If they haven't implemented this then I do not see how you can prevent the battery from charging to 100% whenever the laptop is connected to mains power.

  • \$\begingroup\$ Thanks for your reply Bimpelrekkie. This is encouraging, and I will pursue access to BIOS on the HP forums site. \$\endgroup\$ – Andy Kay Nov 9 '17 at 15:48
  • \$\begingroup\$ HP laptop: if it is a consumer model you can probably forget about the function being present (it would surprise me if it was there). For business laptops it might be there. \$\endgroup\$ – Bimpelrekkie Nov 9 '17 at 15:53
  • \$\begingroup\$ You're right -- an "HP Expert" says that there is no such setting on my laptop. \$\endgroup\$ – Andy Kay Nov 10 '17 at 8:19

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