Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758041Ab0DOXnS (ORCPT ); Thu, 15 Apr 2010 19:43:18 -0400 Received: from mail-pz0-f204.google.com ([209.85.222.204]:40406 "EHLO mail-pz0-f204.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755843Ab0DOXnR (ORCPT ); Thu, 15 Apr 2010 19:43:17 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=k+mgAfnkeHlkkh2ZAdV7OKvxcastsBJw8fYcWMes0RTupiFicYnok8NB18OdwwqG7g hwimNMWwTOrFnftLg1H1ff2eZKzzaTXH/4oLiHyNUkYbrpz/trg1fDyLDo0FeVhzIAUt 0tLfan+gofRbQHmtMVTKab7L/JDGk2vUxWpdk= MIME-Version: 1.0 In-Reply-To: <20100415180200.GA1443@ucw.cz> References: <20100415180200.GA1443@ucw.cz> From: David Rees Date: Thu, 15 Apr 2010 16:42:56 -0700 Message-ID: Subject: Re: Low-Level and Long-Term Battery Control To: Pavel Machek Cc: Mohamed Ikbel Boulabiar , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1422 Lines: 31 On Thu, Apr 15, 2010 at 11:02 AM, Pavel Machek wrote: >> For Laptops, it is better to extract the battery from the Laptop when >> the computer will be on power for a long period. >> I ask if the kernel can do such control without the user intention and >> in an automatic way. >> >> Some BIOS provide to the user to select whether to block the battery >> charging to 50% to make it stand for more time. > > Where have you seen that? I do recall that some older ThinkPads had a utility that would let you determine what "empty" and "full" was by setting artificial limits. It's well known that by keeping batteries from being fully charged/discharged can significantly extend it's useful life although you will suffer from shorter run-times. How sensitive a battery is to this depends on it's exact chemistry, but all are affected by this to some degree. For example, by keeping your battery from charging above 85% and below 15% can increase the number of charge/discharge cycles a large amount often on the order of 5-10 times more charge/discharge cycles - much more than the 30% reduction in total capacity. Limiting to 25-75% will help even more. -Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/