How-To Geek

Hack Apart A 12v Battery for "Free" Watch Batteries [Video]

With this simple hack you can tear apart a 12 v battery to get, well, a lot more (button cell) batteries–$40 more worth.

The secret sauce to this little hack is to purchase the right brands. Many battery companies save on production costs by creating bigger batteries from smaller batteries they already manufacture. In this case button cell batteries are stacked and wrapped to yield a 12v battery. You can do something similar with 9v batteries to yield AA batteries.

As always, proceed with caution and do a little searching online to make sure the brand you’re about to start pulling apart actually contains a set of smaller batteries.

12v Battery Hack [YouTube]

Jason Fitzpatrick is a warranty-voiding DIYer who spends his days cracking opening cases and wrestling with code so you don't have to. If it can be modded, optimized, repurposed, or torn apart for fun he's interested (and probably already at the workbench taking it apart). You can follow him on if you'd like.

  • Published 09/2/11

Comments (10)

  1. Adam C

    Seriously? These are ALWAYS pranks…

  2. steve a

    Hopefully nobody actually believes this….another funny one is getting a lot of AA batteries out of a 6v lantern battery

  3. DaveP in Ohio

    Depends on the particular battery… I have cut open some to find smaller batteries inside.

  4. Alex

    Adam C, KipKay has a whole web series online about stuff like this and I can guarantee you every one of his videos are true.

  5. ridefst

    This is legit, I’ve taken apart 12v batteries to find watch batteries inside, as well as 9v to find something similar to AAA (think they were actually a little bit smaller).
    Dunno about AA out of a lantern battery, but I don’t see why not.
    This is actually fairly common, because most batteries are made up of cells, some just choose to package each cell separately.

  6. b in the rr

    Or you could just go to Dollar Tree, where button cells like this are 8 for $1. Guarantee the 12v costs more than that.

  7. Ken

    @b in the rr

    I think you’ll find in this case its quality over quantity. The cheaper batteries generally dont stand a chance against brand name batteries, Energizer and such.

  8. lesle

    At the local flea market, I buy a 60-pack of AAA batteries for $3. Made in China. They last 3 hours. At 5ยข each, that’s good enough.

  9. SmashD

    @b in the rr @Ken
    Yeah, I hate those ultra-cheap discount batteries. First you think “hey, great, 5 batteries for the price of one” shortly after that you realize that your device lasts max 30 minutes, whereas a better brand would have powered it for a lot longer.

  10. Stephen Mann

    As with most consumer products, you pay more for the package than the product itself.

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