Battery 12 V/33 Ah, gel. Good to know: -Charge cycle: The battery’s life cycle corresponding to the number of charges and discharges calculated based on the IEC 254-1 standard; -Capacity (Ah): The battery’s capacity is, to put it simply, the amount of energy contained in the battery. The capacity is usually measured at 5 Ah (C5). Thus, a battery of, e.g. 500 Ah can provide 100 Ah in 5 hours; -Self-discharge: In addition to the normal discharge, the battery self-discharges 5 to 7 % of its capacity per month. -A fully charged battery should be approx. 12.9 V; -Battery without water = oxyhydrogen gas (Explosive)