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]