You did not receive good advice! I let them talk me into 6 8 volt batteries rather than 8 6 volt batteries. I was immediately unhappy with the range and had to replace the standard 8 volts with 6 Trojan Rangers. My range is now excellent and I couldn't be happier. It was a $1,000 mistake that I won't repeat!
As others have noted, it's the total amp hours of your system that matters.

Batterys
 

Just remember, the more led you have in your cart the more range you will get. Example 8- 6volt battery's will give you more range that 4- 12's, or 6- 8 volt battery's in a 48 volt pack.

Not sure where one would drive in TV that would add up to 80 miles.....I supposedly get 60 miles on my Par Car but not sure I would ever want to drive that far......my northern limit is Glenview from Hillsborough. I plug it in at the end of the day and so far.....no range issues.