If the baterys fine than you either have a short circut, or the electric starter is dissconected/dammaged. Another possibility is that while the battery is charged it is dammedged and has a lower amperage. If it is short on amps that could mean the starter draws to much power and could very well shut everything down. (sort of like on apollo 13). A jumpstart could healp. Also get the hand checked out, it could very well be a sever chemical burn meaning lead acid poisining among other things(at leat its not a ph of 14, in general alkalies are worse for you than acids). Best advice I can offer! :|

if i had to say anything it would be tighten ur battery cables just take a wrench that fits the nut and tighten up, same happened to me, you will have power all day but when u start it if the connection is losose it will die like that