I would feed the solar DIRECTLY to the batteries bypassing the Disconnect (or better yet installing a special disconnect, even if it is the wrench and labeled wire type (You remove the charge line from the battery when you wish to disconnect it).
Use a good charge controller on the solar. A good 3-stage converter .. Well I've accidentally disconnected my batteries on occasion and not even my TS-2000 (Ham Rig) can tell that the batteries are missing (Progressive Dynamics 9180 with wizard). But with a good 3-stage converter it is not needed to disconnect the batteries.. My U-2200's lasted over 8 years (Normal life 7-10 years) even though Ive run 'em way way down a few times (more than I'd like to admit) over those years.. Gone a bit too long without checking the fluid level a few times (Never let 'em get completely dry though, just slightly below the top of the plates) and otherwise abused them.
I really like that PDI Charge wizard. he's .. Well.. a Wizard at charging batteries.
