Let me reframe the query.
At any instance lead acid SMF Battery can accept up to maximum 20% of current capacity. For 12V/26AH battery, it will be 5.2AH.Solar battery charger can pass upto 6A current as per its specification. Take a case where we connected 12V/40Watt solar panel (which can give Max. 2.66A current) and 12V/26AH Lead Acid SMF Battery to solar battery charger. Do you think that any time solar panel may get damage due to excess current (>2.66A) requirement by battery? If yes, what we need to protect solar panel in such condition?