Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!cica!iuvax!mailrus!ames!pacbell!acsdev!phr From: phr@acsdev.net (Paul Rubin) Newsgroups: comp.sys.laptops Subject: Re: External batteries (was: Battery packs for T1000SE) Message-ID: Date: 14 Mar 90 07:34:58 GMT References: <11226@zodiac.ADS.COM> Sender: phr@acsdev.UUCP Distribution: na Lines: 18 In-reply-to: blk@mitre.org's message of 13 Mar 90 15:31:46 GMT In article blk@mitre.org (Brian L. Kahn) writes: Netfolk: shouldn't this approach work on any and all laptops going on a long trip? 1) Take out the internal battery (so you don't try to charge it). 2) Get a bigger and heavier battery than one would normally want to use, either a fancy gelcel/lead-acid thing or a big pack of nicads or even a disposable lantern battery. 3) Connect it to the laptop where the DC transformer usually plugs in. Sure, it might weigh a few lbs, but it could operate for nine or ten hours. Am I missing something? Yes. Laptops often expect the DC transformer to supply a higher voltage than the internal battery (or sometimes not even DC). They then use the battery as a voltage regulator/ripple filter etc. Doing what you suggest would damage many kinds of laptops.