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Dell Laptop Battery electronic problem

Community Veteran
Posts: 17,476
Thanks: 1,479
Fixes: 17
Registered: 06-11-2007

Dell Laptop Battery electronic problem

After posting my  "  Dead Laptop Battery - Revival? " post, I have done some more "research" and saw a couple of videos on how to replace the "internals" of a laptop battery.... as this seemed to be within my scope of electronic skill. (I can use a soldering iron! ! ). I decided to find out about my old Dell Laptop battery.... It states on the casing that it is rated at 9.6 v 4300mAh.... so I opened the casing very carefully, and find 8 rather meaty looking cells with just a number on them.... doing the maths, I came up with  9.6 divided by 8 = 1.2 v and 4300 divided by 8 = 562.5 mAh...... so then googled for a rechargable 1.2v battery with more than 525 mAh...(with tags not the usual domestic style)  of which there are several sizes....
the most likely candidate is about £2.50 to £3.50  which makes the cost about £20 to £30 plus postage.... I have also seen a replacement battery for £28.... so the economics are not great....(the usual replacement is between £35 & £80) depending on who supplies what......)(which makes it a feasible proposition)....
anyway, I digress..... Before I got my soldering iron out, to desolder, the old cells, I decided to put my meter across the end terminals just to make sure it was dead..... Was most surprised to see the meter reading 11.24 volts.... !....
so the question is, the little circuit board controls the charging. (presumably). and also reports to the Battery Health/ Indicator on the setup page.... which states " No Battery Installed"... despite the fact that it is !... (as the battery is charged, I presume that the charging circuit is ok, but the reporting circuit has a defect)
Can anyone advise me, how to go about checking the circuit board, for a faulty component. or where to start looking for someone who could check it out?  I think it would have to be an "electronic enthusiast" rather than a shop, as they don`t seem to want to "mess about".... with things like that....
Is there anyone out there who would be willing to check it out for me?
2 REPLIES
Community Veteran
Posts: 17,476
Thanks: 1,479
Fixes: 17
Registered: 06-11-2007

Re: Dell Laptop Battery electronic problem


UPDATE

Now here is something more intriguing..... I have a spare hdd, with XP on it. .... the task bar icon on the Vista HDD  shows a battery with a red X across it, and right clicking shows "No Battery Installed".  yet if I pull the mains plug.......... the laptop will run for five minutes !.....
so I installed the XP HDD and the task bar icon shows a mains lead only.... hover and it says Power by AC.... right click and it shows "No Battery installed"..... again I pull the mains plug from the laptop, and it runs for 5 minutes...... the icon still shows the mains lead. and it still says Power by AC.....
so.. I am now wondering if Dell, (and possibly other manufacturers) are using the same "chip" technology as in printer cartridges, to show it is empty/not compatible to make us poor sufferers buy only genuine replacements, usually well before they are needed?  (perhaps it also has a 5 minute timer chip on that little circuit board I mentioned above)....

any ideas/ comments welcome......
Community Veteran
Posts: 380
Thanks: 6
Registered: 22-08-2007

Re: Dell Laptop Battery electronic problem

I had something similar with my sisters dell laptop, but I had a spare geniune battery to hand to test with and neither would show up in windows, and flagged up an error at POST on her laptop, but both batteries worked in mine.  Never got to the bottom of it as a few weeks later the motherboard in her laptop gave up the ghost.