Are you planning on using a solar charge controller?  If not, then sticking 24V across a 12V battery isn't going to end well.  Depending on the type of the battery, you could have boiling sulphuric acid or burning lithium to deal with.

In general, big solar panels give more power than little ones, and two solar panels give more power than one.  That should be fairly obvious.  Solar panels could be connected in series for higher voltage, or in parallel for higher current.

Don't assume that a 24V solar panel will actually produce 24V.  It will be less in cloudy conditions, and may be higher in bright sunlight.

Are you planning on using a solar charge controller?  If not, then sticking 24V across a 12V battery isn't going to end well.  Depending on the type of the battery, you could have boiling sulphuric acid or burning lithium to deal with.

In general, big solar panels give more power than little ones, and two solar panels give more power than one.  That should be fairly obvious.  Solar panels could be connected in series for higher voltage, or in parallel for higher current.

Don't assume that a 24V solar panel will actually produce 24V.  It will be less in cloudy conditions, and may be higher in bright sunlight.

Thanks for the reply, but I did not mention 12V battery against 24V Solar panel. Sure Charge controller will be used to control the charging, I have done several Installation that still works for years. But this is about solar laboratory experiment, mentioned in my first sentence, the rest is just an example for more understanding of what I am talking about.