I'm about to make a detailed post about the types of batteries that should me used in toys after receiving my first assignment (California Exotics vibrator) in the mail that was packaged with the wrong type of batteries! Wrong type being material, not size.
I was sent "heavy duty" batteries which are zinc-carbon. "Heavy duty" is a very misleading term considering they are the least effective batteries available today. These types of batteries should really only be used in very low powered things such as remotes, small radios, battery powered alarm clocks, basically anything that you rarely need to change the battery in.
Alkaline batteries (such as Energizer, Duracell, and store brands that state alkaline on them) are zinc manganese oxide. These are the proper type of batteries to use in something that uses a lot of power like vibrators. Basically an alkaline battery has 300% more power available to you (mAh is power, voltage will be the same) and alkalines have a much longer shelf life. This can even affect the strength of something like a vibrator!
To make a long story short: do not use "heavy duty" batteries in your toys, use alkaline only. Also if you are using rechargeables, use NiMh rather than NiCad (nickel-metal hydride, not nickel cadmium) and remember that rechargables usually need to be replaced after a year on average (you'll notice they start to not be as "juicy")
I can't even imagine how many toys may have been packaged with "heavy duty" batteries and rated poorly and even thrown out just because a company that is selling electronics didn't bother to research batteries! Since this is my first experience receiving a toy from California Exotics, maybe my particular vibrator is the exception and not the rule. I truly hope so.
Do other toys generally come with batteries? I mean other than N size and button cell?