<< Click to Display Table of Contents >> Navigation:  Glossary > LOL "Loss-of-load" probability

This value is the probability that the user's needs cannot be supplied (i.e. the time fraction when the battery is disconnected due to the "Low charge" regulator security).  

It may be understood as the complement of the "Solar fraction"  (although it is described in terms of time rather than energy).

During the sizing process, the LOL requirement allows for determining the PV array size needed, for a given battery capacity.

The LOL is calculated using a simplified and fast yearly simulation: the program splits the monthly meteo values into a realistic random sequence of 365 days (according to Collares-Pereira model), each day being divided into 3 periods: morning - day (with solar gains) - and evening.  Then it performs a day-by-day balance, and reports the daily system state, in order to accumulate a realistic "LOL" yearly value.

This process is repeated with different PV-array sizes, in order to find the exact PV size matching the required "LOL".