Connect with us

Charging a laptop battery without the laptop?

Discussion in 'Electronic Repair' started by [email protected], Dec 2, 2008.

Scroll to continue with content
  1. Guest


    I have a Dell laptop which has developed a fault. It doesn't recognise
    its own power supply. A bit of internet research reveals that this is
    a common fault on this particular model, and it's a fault with the
    motherboard, so an expensive repair. At the moment for me the fault is
    intermittent. Sometimes the power supply is recognised and the thing
    will run happily from the mains and charge the battery, sometimes it
    isn't and it runs from the battery. Pretty soon a time will come when
    the battery goes flat, the power supply won't be recognised at all and
    it will be screwed unless I replace the motherboard.

    To get to the point I could easily keep the PC running if I could
    charge the battery without it being in the laptop. Anyone know what my
    chances are? The battery has eight pins. I presume it has some
    circuitry inside which means it's not as easy as guessing the right
    two pins and putting a current across them.


  2. jakdedert

    jakdedert Guest

    While it may be a 'common fault', are you sure that the supply you are
    using is a genuine Dell supply? I only ask because other companies sell
    a supply that looks very much like the Dell original, uses the same
    input and output cords and even has a representation of the Dell logo
    molded into the face....but is NOT a Dell supply, and will NOT charge my
    Dell laptops.

    *It will run them, but not charge the battery.*

    Closer examination reveals that it's really not much like a genuine
    supply. It's much lighter in weight. The quality of the cabling is
    markedly inferior. It doesn't have the rubber cable retainer strap.
    There is no Dell information on the info sticker. It says at the top,
    'Replacement AC Adaptor' and gives a few specs. At the bottom it says
    'Made in China'.

    I got it with a Dell laptop from Craigslist. The original owner
    complained the battery wouldn't charge. Connection to a genuine Dell
    supply fixed that problem.

  3. Guest

    Thanks for the idea Jak, but the charger is definitely OK. It came
    with the laptop from Dell, and has worked perfectly for the last two
    years. The fault has only developed recently, and not only will the
    charger now not charge the battery, it will not power the laptop at
    all. This is apparently a motherboard problem and has nothing to do
    with the charger itself. However, the laptop will run fine from a
    charged battery. Hence my need to charge the battery some other way.
  4. Adrian C

    Adrian C Guest

    Sounds like a broken DC jack. Not that hard to remove the motherboard,
    desolder the jack and replace with a new jack purchased from eBay. Or
    have someone do it for you. It's not expensive work.

    Plenty of web sites that will show how, and the service manuals are
    freely downloadable from dell online.
  5. jakdedert

    jakdedert Guest

    You're probably on the right track, but it might be worth the trouble
    to--at least--borrow another ps just for confirmation. Some Dells are
    pretty sensitive to having the correct supply. That might also
    translate to being sensitive to the condition of even genuine Dell
    bricks. I've had a couple of those fail on me, although not in the same
    fashion as you describe.

    Otherwise, the advice on resoldering the ps jack sounds like a go....

    Also, post the model #. If you did before, I missed it; but it's your
    best chance at finding spares or specific information.

  6. Guest

    Thanks for all replies. The laptop is a Dell XPS M1210.

    The reason I've come to the conclusion that the problem is more
    serious than the power supply or a loose power jack is a few postings
    around the net such as these:
    It's a problem which a few people have and no one seems to have found
    an easy solution by just soldering on a new jack. The advice from Dell
    (according to those posts) seems to be that a new motherboard is

    Michael, thanks in particular for your offer to post information about
    circuit diagrams and software concerning charging batteries. Frankly
    that sounds like it's going to go way over my head and be beyond my
    minimal understanding. I guess I was hoping someone would tell me that
    I could just put 12v DC across pins 3 and 5 for two hours and charge
    it and keep the laptop working that way. It sounds like I was being a
    little naive, so I thing it may be a trip to the repair shop and a new
    motherboard (or maybe just a new laptop!).


  7. Adrian C

    Adrian C Guest

    That laptop has a 3-wire connector. Some folks may have had a 2-wire
    connector installed or there may be some other connection problem.


    As mentioned on this page, an error message will be seen regarding an
    Unknown adapter type if the data center pin is not making a good connection.

    With what you have, and a meter - I'd start making continuity tests.
  8. Adrian C

    Adrian C Guest

    BTW Replacement jack socket in ebay (UK) #190269916134 Less than £5!
  9. Andy Cuffe

    Andy Cuffe Guest

    This may not apply to this model, but I've seen a lot of older Dell
    laptops with cracked solder connections on a surface mount inductor
    near the power jack. It's close enough to the power jack to receive
    stress from flexing. The connections usually don't look that bad
    under casual inspection. I would re-solder everything near the power
    Andy Cuffe

  10. Mike S

    Mike S Guest

    Do you have a port replicator?
    I own a Dell Inspiron 8500 and it only charges the battery if the AC adapter
    is plugged into the port replicator which is then attached to the bottom of
    the laptop. I have confirmed that the adapter is good and the problem is
    not the DC jack on the motherboard. I now always have it tethered to the
    port replicator for charging.
  11. Guest

    I don't know about Dells, but for Lenovos you can buy standalone
    battery chargers. Have a look on eBay.

    Another Bay alternative is to buy a dead "spares or repairs" machine
    with a different fault. Even if it won't boot, it will hopefully
    charge a battery.

  12. Guest

    when you find out let me know
  13. jakdedert

    jakdedert Guest

    IMM, the OP has not thoroughly diagnosed the problem. His internet
    research could very well be valid; but without real-world testing, it's
    still only opinion. To date, he has not indicated whether he has tested
    the power supply. In fact, he stated that it categorically could 'not'
    be the problem (although that answer was in response to a different
    query, regarding aftermarket supplies which are known to produce nearly
    the same symptoms).

    Since most recent Dells use the either the PA 12 (65 watt, original
    equipment for his unit), or the PA 10 (90 watt) supplies, it's pretty
    easy to find someone with a known-good supply to sub. In fact, the PA
    10 is also a substitute for the any laptop supplied with a PA 12, making
    it even easier to find a sub. IMO, this is good policy from Dell. I
    wish other makers followed this model of not tying their supplies to a
    particular unit.

    Given that this is least expensive possible solution--as well as the
    cheapest/easiest--I urge the OP to at least explore the possibility.
    Try your supply on a known-good laptop; or try a known-good supply on
    yours. If it turns out to not be the case, obviously he'll have to
    explore others.

  14. Adrian C

    Adrian C Guest

    Hope so :)

    Doing a little research, the extra pin connector is for a Dallas 1-Wire
    serial id chip that Dell have built into their own manufactured power
    supplies, to limit their customers to only purchasing them and not a

    If it is the PSU at fault, further googling suggests that replacement
    supplies from Dell are actually not that horrendously expensive (e.g.
    £33 inc delivery for UK)
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day