I have a battery charging system prob to it only charged at 12.50 nomatter how much throttle I gave it. I just baught it and the bAttery was bad I took to battery store they put new one in backwards I figured out what they did after it wouldnt start I put it in right and it started right up then next day New battery was dead anyone got any advice on where to start?

 

I would check the R/R I had the same issue, new battery but wouldn't charge pulled the R/R and found 2-3 of the main wires are melted

 

Might be a long shot, but try charging the battery overnight for at least 12-14 hours. It might just recover. If it does charge up ok, fit it to the bike and run the engine. Put a volt meter across the terminals and see if the voltage rises as you rev the engine. You should see (sorry if you already know all this!) a rise in voltage of 13.5-14.2 volts if all is well with the charging system. I can't understand why the battery was fitted the wrong way round though! The leads won't usually reach the terminals if it is not the right way round in the frame. As the last reply, if no luck with my suggestions substitute or buy another R/R. Good luck!