Some solar systems can actually drain a battery at night or in the shade, oddly enough, but what I think BFL13 meant was maybe it was 10 amps going IN to your battery from the panels rather than 10 amps being pulled out of your battery. You said you have 200 watts of solar....10 amps almost sounds right...
I'm still confused as to why you get ten amps between the negative battery post and ground, but much less than that when you measure from the negative battery post to the end of the negative wire. The wire should connect to the frame (ground). What are you using for you ground point when measuring this? What's puzzling about this is that they should be the same.