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sneezo

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sneezo

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June 23rd, 2026 06:48

Precision 7740 Replacement battery no good

I've bought many Dell laptops, and multiple replacement batteries.  The last one I bought was rubbish.  After 4 months, the battery life (like-for-like usage) is at the same level the original battery after 4 years.  Its now out of warranty but its disappointing to need another replacement so soon.  I've tried to contact support for advice but can't make it through the bot wall!

(edited)

  • anne_droid

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    Posted June 23rd, 2026 09:03

    Please can you confirm the Make Model and OS, along with any configuration details like touch screen, backlit keyboard, SFF or tower etc etc.

      Kind Regards  

                                         

      anne_droid

  • sneezo

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    Posted June 23rd, 2026 09:54

    Precision 7740 laptop running Win 11. Backlit keyboard. No touch screen.

    The point is that its a like-for-like environment. One battery lasted 4 years; one lasted 4 months.  Same machine, same environment, same usage pattern.  In my mind, the only difference is the battery.

  • anne_droid

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    Posted June 23rd, 2026 10:41

    Hi

    In my mind...

    Was it a DELL or lookee-likee replacement?

    Is there a fault on the Main Board causing the early demise of the replacement (and perhaps the previous),and don't rule out the PSU?

    4 months, still under warranty/guarantee.

      Kind Regards  

                                         

      anne_droid

  • sneezo

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    Posted June 23rd, 2026 11:15

    Thanks.

    Genuine Dell.  A main board fault is possible.  How would I investigate?

    The battery report still suggests that battery is OK, so the customer service bots declined to get involved.

    I've attached the battery report that shows predicted battery life of 5+ hours plus recent usage report of < 2 hours.

  • ejn63

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    Posted June 23rd, 2026 14:01

    As this is a system that's about 6-7 years old, even if it was sold as "new", it's very possible the battery could be aged -- batteries deteriorate from age as much as they do from use.

    On the battery is the Dell part number -- post that and someone can look at the string and determine the date of manufacture of the battery.

  • sneezo

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    Posted June 23rd, 2026 14:36

    Thanks. It was bought as a genuine replacement battery from Dell on 09/02/26. 

    Dell purchase ID: <To protect your privacy, all private information was removed from this public post. DELL-Admin>

    (edited)

  • ejn63

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    Posted June 23rd, 2026 14:53

    It could still be multiple years old -- you will need to supply the complete Dell part number on the battery, not just the order number, for anyone to advise.

    Generally, new OEM batteries are produced for 3-4 years following a system's release, meaning the battery could date from anywhere between 3 years ago and 6-7 years ago - in other words, it may have been sold as new but could have been old stock.

  • sneezo

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    Posted June 23rd, 2026 14:54

    Is this the part number? CN-00WMRC-SLW00 58L-400S-A11

    If this was sold from a stock of old batteries (as new), how can I ensure it doesn't happen again if I order another one?

  • ejn63

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    Posted June 23rd, 2026 15:20

    That battery was made in August 2025, so it's not that old -- under a year.  That's assuming it is OEM.

    How could a battery that's was purchased only four months ago be out of warranty?  The warranty from Dell should be one year.

  • sneezo

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    Posted June 23rd, 2026 15:31

    The bot army will only approve a replacement if their diagnostics think the battery is faulty, which is why I've been desperate to speak to a human.  Any suggestions on how to proceed?