I have so far bought two of these pumps at Target and neither worked.  I purchased the first and charged it for 12hrs.  It was then unplugged and turned on.  It ran weakly for about 10 seconds, then shut off.  The wall outlet was working, so it had to be a product issue.  I returned it and got another unit of the same type.  The exact same problem occurred.  I tried changing wall outlets and charging it for the max of 24hrs in the owners manual.  It still didn't work.  I don't usually don't give 1 star reviews, but after having two fail in a row, I have no basis to give anything else.