Balance-of-system loss

Balance-of-system loss, also called system losses, appears in the IEA PVPS analytical monitoring parameter list under the symbols lS and LS. The instantaneous form, lS, has no unit, while the form LS is reported in hours, the same unit used for yields. The balance of system covers all the equipment that lets the electricity the PV array produces be delivered properly to the load. That usually means the array mounting structures and the power-conditioning equipment that changes the DC output into the AC form and magnitude the load needs. The balance of system can also include storage such as batteries, which let PV energy be used at night or on cloudy days. The abbreviations BOS and BoS are both used for balance of system in manuals and O&M guidance.

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• sentence 1: support check: partial - The row lists 'system losses' with symbols lS, LS, but it doesn't mention 'balance-of-system loss' as an alternate name or the IEA PVPS list by name beyond the row.
• sentence 2: support check: partial - Units '- , h' map to lS and LS in order, but the passage doesn't say that hours is the unit used for yields.
• sentence 6: support check: partial - BOS and BoS both appear as balance of system abbreviations, but BoS is not shown in manuals or O&M guidance specifically, and the passages show 'Balance of Systems' for BoS.
• sentence 1: review: partial - The row confirms 'system losses' with symbols lS and LS, but nothing in it equates that parameter with balance-of-system loss. -->