Multiple Voting in One Node
I've not had much luck with the plus1 module.  The 7 version is wonky.  If you're just looking for a plus 1 or like function and your fixed on the voting api then vote up/down May work for you.  You can create multiple voting fields and they are tracked separately as a field.  The widget may cause some layout issues so may I suggest using flags instead.  

Why?  It's easy to add a plus1 type feature and flags can be formatted using views or flag_create_link() so you can put it every where and wrap it in any CSS div or span.  You can have as many as you'd like and it's all in the db and available to views.  You can even use rules so the system can react on a flag.  I've moved away from voting api in favour of flags.