u can but a correctly wired pump should be on a relay at the pump so its getting whatever the battery is charging at.
pics
http://i33.photobucket.com/albums/d71/Mattsv8_03/SSPX4768.jpg
http://i33.photobucket.com/albums/d71/Mattsv8_03/SSPX4769.jpg
notice the top first design pump. yea its still working i had a new a1000 fail within the first two passes of its life? supposed to be better but i dont kown we will see how thisone holds up