Battery does what he wants

After buying my Canon 60D, I realized quickly that a second battery is needed. After many recently left lying money I thought to myself, you can give sometimes satisfied with a second-rate product. Think again.
The battery gave me problems from the beginning. In a not unimportant shoot complete objection. After an email to the manufacturer, these problems can occur in the early days. Have I believed again I was wrong. In short, my battery does what he wants. Now and then he fails despite full battery indicator his service, but it also happens that the fully charged battery pack when inserted again announces emergency charging.
My advice, prefer to invest in an original battery. Costs more, but prevents frustration and a possible double investment.