Designing the system
Series or parallel, MPPT or PWM, how big a controller and how thick a cable. The calculable half — standards and arithmetic rather than opinion.
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Arc Fault Protection in PV: Why DC Arcs Persist
A DC arc has no zero crossing to extinguish it. Series against parallel faults, and why repeated trips are an instruction to inspect rather than reset.
intermediate -
Battery Bank Sizing: From Daily Load to Nameplate Capacity
Learn how to size a battery bank correctly: daily load, depth of discharge, round-trip efficiency, days of autonomy, and temperature derates.
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Charge Controller Sizing: Matching the Array to the Controller
Learn how to size a charge controller correctly: calculate array current and voltage, apply temperature margins, and avoid common missteps.
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Combiner Boxes: Where Strings Meet and Fuses Appear
Several strings joined at one point, and the protection question that follows: fuses are needed once enough parallel strings can backfeed a fault.
intermediate -
Depth of Discharge: What It Means for Battery Life
Depth of discharge (DoD) defines usable battery capacity. Learn how DoD affects cycle life, why chemistry matters, and how to calculate it.
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Hybrid Inverter: Grid, Battery, and Backup in One Box
Learn what a hybrid inverter does, how it combines grid-tie, battery charging, and backup, and the key design considerations for your solar system.
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Microinverters Versus String Inverters: What Decides
Per-module conversion against one central unit. Shading decides it, failure modes differ, and roof access matters more than the datasheet.
intermediate -
MPPT vs PWM Charge Controllers: How They Differ
Understand the difference between MPPT and PWM charge controllers: how each works, efficiency, voltage handling, and when PWM is still the right choice.
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PV Panel Voltage and Current: Voc, Vmp, Isc, Imp
Learn solar panel electrical ratings: Voc, Vmp, Isc, Imp—how they're measured, temperature effects, and comparing to inverter limits.
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Rapid Shutdown: Why a Live Roof Is the Problem
A PV array cannot be switched off, only disconnected. Rapid shutdown addresses what firefighters face on a roof, and the specifics live in the adopted code.
intermediate -
Series or Parallel Solar Panels: Which Wiring to Choose
Learn how series vs. parallel wiring affects voltage and current, and choose based on inverter specs, shading, and temperature. Includes math and mistakes.
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Sizing an Inverter to a Solar Array: DC/AC Ratio
Learn how to size a solar inverter to an array using the DC/AC ratio. Understand clipping, temperature derates, and design margins for optimal performance.
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Solar Battery Types: Lead-Acid, AGM, and Lithium
Compare lead-acid, AGM, and lithium batteries for solar: usable depth, cycle life, charging, and temperature effects. Understand the trade-offs to choose correctly.
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Solar System Grounding: Equipment, System, and Surge Paths
Understand solar system grounding: equipment vs system grounding, bonding, and surge protection placement. Learn what must be bonded and why.
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Solar Wire Size and Voltage Drop: How to Calculate
Learn how to calculate solar wire size based on voltage drop, current, and distance. Understand the 3% rule and temperature derating for safe PV design.
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Why an Array Never Makes Its Rated Power
Understand why solar panels produce less than rated power. Explore temperature, soiling, mismatch, wiring, and inverter losses, plus how to diagnose low output.