batteries - agm? and swapping with solar

[kampingkris]

Hello electrical experts. Opinions needed.
Need new batteries as they are 7 years old. AGM? Heard they don't last much longer and are pricy. Worth the investment?
Next, we have a solar controller. The instruction manual gives a dire warning of not disconnecting the batteries unless the solar panel is disconnected. If charging, it says the solar will/can create a spike which can damage 12 volt stuff if battery disconnected.
Will swapping the batteries out in a garage eliminate that issue? Otherwise, it appears we have to disconnect the panel wriring from the back of the controller in the closet.

I'm hoping our mechanic is aware of all of this, but I like to be informed to make sure it all happens correctly.

Also, our chasse batteries are also hooked to the solar (we are also getting new batteries for that since they are 6 years old)
 

[rls7201]

A proper solar installation will have a switch between the panels and the controller.

 

Richard