How many extra batteries should you bring, and where can you buy more?

[haverfordfords]

I look at threads addressing this question and all the sources listed didn't work out, as the treads were outdated.

Our local suppliers of Exide batteries never heard of the ES18-12... where have you been able to buy these? Is there a specific place you have been successful in obtaining extra batteries from? Any help would be greatly appreciated.

Also, how many batteries do you think we should have for regionals? Someone told me three - one charged, one charging, one in the bot - and cycling through them.

Thanks in advance,
Jason