I just went through trying to figure this out myself the hard way.
Look at the labels on the adapters and look at the output. It should say something about voltage, and then 500ma or 1000ma etc, if that is not listed it will say .5A or 1A etc.
You need a MINIMUM of 1000ma, or 1A meaning it needs and output of at least 1 amp. I purchased 2 amp adapters and love it.