Connecting batteries

[ianess]

What are the different effects of connecting batteries either in series or in parallel?

Does connecting them  end up with double the voltage or double the amperage?  I`m looking for twice the power but at the same voltage.    Many thanks. 

[FlyingScot]

Connecting in series increases voltage.  Connecting in parallel increasing ampere-hour ratings.

[ianess]

Many thanks FlyingScot.

I also tried Googling and found this link:  http://www.zbattery.com/zbattery/seriesparallel.html

Should have tried that first to avoid timewasting....sorry.