Lesson 1Sizing and specifying cables and protection: voltage drop, Ampacity, derating, and standards to referenceSize PV cables and protections in Botswana using ampacity, drop limits, and derating, referencing standards to match fuses, breakers, and environments for reliable, code-compliant installations.
Conductor materials and insulation typesAmpacity, grouping, and temperature deratingVoltage drop limits and cable lengthFuse and breaker selection for stringsRelevant IEC and NEC cable standardsLesson 2PV module types and characteristics: monocrystalline, polycrystalline, bifacial, temperature coefficients and power toleranceReview monocrystalline, polycrystalline, and bifacial modules suited to Botswana's heat, covering efficiency, temp responses, tolerances, and reliability for climate-appropriate selections from datasheets.
Monocrystalline vs polycrystalline modulesBifacial modules and albedo conditionsTemperature coefficients and hot climatesPower tolerance and binning strategiesDegradation rates and warranty termsLesson 3Module electrical parameters: Vmp, Imp, Voc, Isc, STC vs NOCT, IV curves and implication for string designExplain module params like Vmp, Imp, Voc, Isc, and IV curves under STC/NOCT, applying them to forecast array performance and string/inverter pairings for Botswana's varying conditions.
STC vs NOCT ratings and test conditionsVoc, Vmp, Isc, and Imp definitionsReading and interpreting IV curvesEffect of irradiance and temperatureImplications for string and inverter designLesson 4Earthing and lightning protection basics and local regulatory checklist for rooftop PVIntroduce earthing, bonding, and lightning safeguards for Botswana rooftops, with checklists for equipotential bonds, surge routes, and terminations aligned to local regs for enhanced safety.
Functional vs protective earthingBonding of modules and mounting railsLightning risk assessment basicsAir terminals, down conductors, and SPDsRegulatory and inspection checklistsLesson 5String sizing: maximum input voltage, MPPT voltage window, number of modules per string, and cold-temperature correctionSize strings considering inverter limits, DC max, MPPT ranges, and cold temp adjustments for Botswana's occasional chills, ensuring safe module counts per climate and grid requirements.
Reading inverter DC input specificationsUsing module Voc and temperature dataCold-temperature voltage correctionMPPT window and operating marginsTools and spreadsheets for string sizingLesson 6Inverter options and tradeoffs: central/string inverters, string inverters with DC optimizers, and microinvertersCompare central, string, and module-level inverters for Botswana PV, weighing efficiency, reliability, maintenance, and flexibility for homes, businesses, and larger scales in local applications.
Central inverters for large ground-mountsString inverters for rooftop systemsString inverters with DC optimizersMicroinverters for module-level ACRedundancy, availability, and serviceabilityLesson 7Balance-of-System (BOS): DC wiring, fuses, combiners, DC disconnect, AC breaker, AC combiner, earthing/grounding and protective devicesCover BOS elements like DC/AC wiring, combiners, disconnects, breakers, grounding, and protections in Botswana setups, linking functions to safety, compliance, and durability for robust systems.
DC cable routing and segregation rulesString combiners and overcurrent protectionDC disconnects and isolation requirementsAC breakers, panels, and labelingEarthing, bonding, and fault pathsSurge protective devices for PV arraysLesson 8Choosing inverter topology considering partial shading, mismatch, monitoring, and costSelect inverter types based on shading tolerance, mismatch handling, monitoring needs, and costs in Botswana, using metrics to compare central, string, and module approaches quantitatively.
Mismatch and partial shading loss mechanismsCentral vs string vs module-level layoutsMonitoring granularity and data needsCAPEX, OPEX, and LCOE comparisonsDesigning for future expansion and retrofitsLesson 9Module-level power electronics: optimizers and microinverters—installation, performance, wiring complexity and failure modesExamine optimizers and microinverters for Botswana residential and commercial PV, covering installs, wiring challenges, monitoring gains, efficiency, reliability, and common failures in practice.
Optimizer vs microinverter architecturesLayout and mounting best practicesAC and DC wiring topologiesMonitoring, diagnostics, and shutdownCommon failure modes and mitigation
