Roguebooks, do you have a controller, or just the zamp port with a fuse?
The unit John posted does not have a controller. If you simply have a port, and inline fuse, wired to the battery, you need a controller, also. That's the way most "solar ready" options are wired. If so, Click through the options in John's post for a suitcase INCLUDING controller. It's a bit more.
Sherry