Two battery’s being charged?

[steplift20]

Phatdaddy I think you know what Im interested in doing.
Use one but charges both while the switch is on to battery 1 ,but charges both
The issue I have with my switch is that its located by the battery s under the panel located in the splash well. So for me to switch it ,its a pain in the. #$&* I should move the switch but Im lazy and its been there for years , out of the elements.

Pipedream so you always run with the two batterys hooked together? Thats good but if your batterys die you dont have a backup. Am I right?