The accumulators consist of lead plaques, which have the ability to store energy and hand it over to us when requested. Especially in solar (photovoltaic) systems, accumulator discharging is quite frequent and in depth.
In depth discharging occurs when we use in short time duration, for example within 24 hours, a substantial part of the accumulator’s capacity (from 25% to 80% of its total capacity). Each discharging of this sort is characterized as discharging cycle. Each battery of deep discharging features a curve of discharging cycles (see technical manual of each battery). This curve shows how many cycles the battery can offer for each depth of discharging.
For instance, a battery may be able to last for 1,000 use cycles with discharges of 30% depth, or 600 use cycles with discharges of 50% depth etc.