In an email, Kirk said that he has found that ‘dead’ laptop batteries often have only a single cell that’s bad.\u00a0 I have torn apart some Dell laptop batteries, and found that they have a PC board that has some kind of battery management capability. \u00a0 I also found that the five or six cells are often the same size as the lithium rechargeable cells commonly known as 18650.\u00a0 This number is the size of the battery in millimeters.\u00a0 However, the 18650 cells may have a button on one end signifying that it’s the positive end.\u00a0 The cells in the laptop battery may have no button, and are typically spot welded to metal straps that connect them in series.\u00a0 These straps may be peeled off to remove the single cells.\u00a0 Then the cells can be recharged and tested to find if they hold a charge.<\/p>\n
First off, the battery management board may keep in its memory how many times the battery has been charged.\u00a0 Even though the cells may seem to have some life in them, the management may have shut down the battery because it reached a certain recharge limit, and what life that’s left in the cells is very limited.\u00a0 So don’t expect to get much from the cells.<\/p>\n
Another point that I want to strongly emphasize is that these cells are lithium cells, and have been known to explode or catch on fire if they are charged too fast or overcharged.\u00a0 That is another reason why the battery management board is used – to monitor the charging.\u00a0 So I highly recommend that the correct charger be used to recharge these cells.\u00a0 I bought mine from Dealextreme.com for under ten dollars U.S.\u00a0 It will also charge RCR-123 cells.<\/p>\n
I have seen lithium rechargeables charge up to more than 4.2 volts.\u00a0 On discharge, they may fall to as low as 3 volts.\u00a0 So it may be necessary to use a DC to DC converter to get a stable output.<\/p>\n","protected":false},"excerpt":{"rendered":"
In an email, Kirk said that he has found that ‘dead’ laptop batteries often have only a single cell that’s bad.\u00a0 I have torn apart some Dell laptop batteries, and found that they have a PC board that has some kind of battery management capability. \u00a0 I also found that the five or six cells <\/p>\n (Read More…)<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[],"class_list":["post-7696","post","type-post","status-publish","format-standard","hentry","category-electronics"],"_links":{"self":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/7696","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7696"}],"version-history":[{"count":8,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/7696\/revisions"}],"predecessor-version":[{"id":7740,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/7696\/revisions\/7740"}],"wp:attachment":[{"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7696"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7696"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rustybolt.info\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7696"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}