It depends how you hook them up, you can take 5 12volt batteries and hook them up to make one long lasting 12 volt, or you can make it a 60 volt. If you hook pos to neg to pos to neg and so on, you will increase the voltage. And at the end, the neg would be grounded and the pos would be hot. Is that what you meant?
Grounding one end of a group of batteries connected in series will only put that end at ground potential. It should not change the voltage or amperage of the circuit unless other places of the circuit are grounded too.