> You have to find out what the MOTOR voltage is.  If it is 12 volts, then yes
> batteries are connected "in series".  Just get an adapter and solder it into
> the battery terminals.  But sometimes batteries are connected in ways to get
> different voltages.  Like the eight batteries could be hooked up as two
> stacks of four 1.5 volt batteries joined "in parallel" to give you six
> volts.  That provides less voltage, but longer output capacity than one
> stack of four 1.5 volt batteries.

Indeed, it's probably good to be on the safe side and check the
voltage at the motor; but usually with battery operated consumer
products, it's a fairly safe assumption that they're all series. Given
the unpredictably wide quality range of disposable batteries, plus
utter ignorance or indifference on the part of consumers which
inevitably leads to anarchic mixing of used/new alkaline/carbon
rechargeable/disposable batteries within one device,  parallel wired
batteries show up only in very specialized devices and only with
large, dire warning stickers. Usually if the manufacturer wants more
"ampacity", they'll build it to take AA instead of AAA, or D's instead
of C's. Otherwise, the first time Joe Hamfist crams four used, nearly
dead cheap chinese batteries in parallel with for brand new Energizers
and the 6-plus enthusiastic Energizer volts push through the
3-and-change weak volts of the dud batteries and crack 'em open, Joe's
going to be very irate over the battery goop eating holes in his
upholstery.

--
John Bange
'90 Vanagon - "Geldsauger"