Storage of lead-acid batteries
Neither approach is good.
See http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

Most stationary batteries are kept on float charge. To reduce stress, the so-called hysteresis charge disconnects the float current when the battery is full. As the terminal voltage drops due to self-discharge, an occasional topping charge replenishes the lost energy. In essence, the battery is only “borrowed” from time to time for brief moments. This mode works well for installations that do not draw a load when on standby.
Lead acid batteries must always be stored in a charged state. A topping charge should be applied every six months to prevent the voltage from dropping below 2.10V/cell.

I believe the main issue, relevant to this question, is sulfation

Solar cells and wind turbines do not always provide sufficient charge, and lead acid banks succumb to sulfation.

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During prolonged charge deprivation, however, the amorphous lead sulfate converts to a stable crystalline that deposits on the negative plates. This leads to the development of large crystals, which reduce the battery’s active material that is responsible for high capacity and low resistance. Sulfation also lowers charge acceptance.