Can a car battery Solar maintainer damage battery?

A solar charger around 2.5V, plugged into my always-on cigarette lighter. Charging into my Optima red top battery in my 01 Ford Explorer. I do not drive my SUV for sometimes a week at a time and that can cause battery to get low(and I have to call AAA). -No battery drainage or alternator issues, just inactivity-

So I want to get this battery maintainer but I fear it might overcharge the battery if left on for for a week or two at a time. I do not know a lot about batteries so please let me know if my concerns are legitimate.

Thank you
Added (1). Im probably going with a 5W panel. Will it overcharge the battery at all, even if left charging for an entire year?(hypothetically)?

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