The basics
Alternating Current (AC) — The type of electricity your house, appliances, and the grid all run on. Solar panels don’t produce AC, which is why every solar system needs an inverter.
Direct Current (DC) — The type of electricity that solar panels generate and that batteries store. DC has to be converted to AC before it can power your home or be exported to the grid.
Kilowatt (kW) — A measure of power: how much electricity something can produce or consume at a single moment. A 6.6kW solar system can produce up to 6,600 watts at peak output.
Kilowatt-hour (kWh) — A measure of energy: how much electricity is produced or consumed over time. One kilowatt running for one hour equals one kWh. Your electricity bill is in kWh, and battery capacity is measured in kWh — not kW. Mixing them up is one of the most common quote-reading mistakes.
Watt (W) — The basic unit of electrical power. 1,000W = 1kW. Individual solar panels today are typically rated between 400W and 500W.
Watt-peak (Wp) — The maximum output of a solar panel under standardised lab conditions (see STC). It’s the number printed on the spec sheet, but real-world output is almost always lower than the Wp rating because real conditions are rarely as ideal as the lab.
Solar panels
Bifacial panel — A panel that generates from both its front and back surfaces. They outperform standard panels when mounted to let light reach the rear (above a reflective surface, raised off a roof) but the gain on a typical residential pitched roof is modest.
Degradation — The gradual decline in a panel’s output over time. Most quality panels lose 0.25–0.55% per year, which is why performance warranties guarantee a minimum output (commonly 85–90%) at the 25- or 30-year mark.
Efficiency — The percentage of sunlight a panel converts into usable electricity. Most residential panels today sit between 20% and 23%. Higher efficiency mainly matters when roof space is tight; if you have plenty of room, a slightly less efficient panel can be the smarter buy.
Half-cut cell — A panel design where each cell is cut in half, halving the current per cell and improving shade tolerance and internal losses. Now standard on most quality panels.
Module — Industry shorthand for a single solar panel.
Monocrystalline (mono) — Panels made from a single continuous silicon crystal. More efficient and space-efficient than polycrystalline, and the dominant residential technology today.
Photovoltaic (PV) — The technical name for technology that converts sunlight directly into electricity. “Solar PV” and “solar panels” mean the same thing.
Polycrystalline (poly) — Older-generation panels made from multiple silicon crystals. Cheaper but less efficient than mono, and largely phased out of residential installs.
Standard Test Conditions (STC) — The lab conditions panels are rated against: 1,000W of sunlight per square metre, a cell temperature of 25°C, and a specified air mass spectrum. Real-world conditions rarely match this, so actual output usually sits below the STC rating.
Temperature coefficient — How much a panel’s output drops as it gets hotter, expressed as a percentage per degree above 25°C. In Australian summers this matters: a panel rated -0.30%/°C loses less in the heat than one rated -0.40%/°C.
Tier 1 — A Bloomberg NEF classification based on the financial bankability of a panel manufacturer — not the quality of its panels. It tells you the maker is large and stable enough that banks will finance utility-scale projects using their products. It is not a quality certification, despite often being marketed as one.
Inverters
AC-coupled battery — A battery that has its own inverter and connects to your solar system on the AC side. Easier to retrofit to an existing solar system, but slightly less efficient because power is converted multiple times.
DC-coupled battery — A battery that shares a hybrid inverter with the solar panels and connects on the DC side. More efficient than AC-coupled and usually the better choice for a new install.
Hybrid inverter — An inverter designed to manage both solar panels and a battery from one unit. Buying a hybrid up front (even with no battery initially) makes adding a battery later much cheaper and simpler.
Microinverter — A small inverter attached to each individual panel rather than one central inverter for the whole array. They handle shading and panel-level faults better and provide per-panel monitoring, but cost more and put electronics on every roof position.
MPPT (Maximum Power Point Tracker) — A circuit inside the inverter that continuously adjusts the load on a string of panels to draw the maximum power available given current sunlight, temperature, and shading. The number of MPPTs matters: each MPPT controls one independent string, so a 2-MPPT inverter can handle two roof faces with different orientations or shading, while a 1-MPPT inverter forces all panels to behave identically.
Optimiser — A small device fitted to each panel that does some of what a microinverter does (panel-level tracking and monitoring) while still using a central string inverter. A middle-ground option for shaded or complex roofs.
String inverter — A single central inverter that all panels feed into via “strings” of panels wired in series. The most common and cost-effective inverter type for straightforward residential installs.
Batteries
Backup / Blackout protection — The ability for a battery to keep nominated circuits running during a grid outage. Not all batteries include this by default; many require an extra “backup gateway” or “backup box” added at install, often at extra cost.
BESS (Battery Energy Storage System) — Industry shorthand for a battery system, mostly seen on commercial quotes and technical documentation.
Cycle life — The number of full charge-and-discharge cycles a battery is rated for before its capacity drops below a defined threshold (commonly 60–70% of original). Modern LFP residential batteries are typically rated for 6,000–10,000 cycles.
Depth of Discharge (DoD) — How much of a battery’s nameplate capacity you can actually use. A 10kWh battery with 90% DoD has 9kWh of usable capacity. Manufacturers limit DoD to protect battery health and extend cycle life.
LFP / LiFePO4 (Lithium Iron Phosphate) — The battery chemistry used in most quality residential batteries today. LFP is more thermally stable, longer-lasting, and safer than older lithium chemistries, at the cost of being slightly heavier per kWh.
Nameplate capacity — The headline kWh figure printed on the battery, before any DoD reduction. Always compare on usable capacity, not nameplate.
NMC (Nickel Manganese Cobalt) — An older lithium chemistry, more energy-dense than LFP but more thermally sensitive. Some brands still use it, but the residential market has moved heavily toward LFP.
Round-trip efficiency — The percentage of energy you actually get back out of a battery after putting it in. A 90% round-trip efficient battery returns 9kWh for every 10kWh stored; the rest is lost as heat during conversion.
Usable capacity — The amount of energy you can actually draw from a battery in normal operation, after DoD limits. This is the number that should drive your sizing decisions.
VPP (Virtual Power Plant) — A program where your battery is networked with thousands of others and operated collectively, with the operator paying you (in credits, cash, or cheaper rates) for access to your stored energy at peak times. VPPs can boost a battery’s financial return, but they limit your control over when it charges and discharges.
Installation & your site
Azimuth — The compass direction your panels face, measured in degrees from north. In Australia, true north is generally optimal, with east- and west-facing panels producing roughly 85–90% of a north-facing array’s annual total.
Isolator — A switch that lets an installer or emergency responder safely cut power to part of the system. There are usually several — at the panels, at the inverter, and at the switchboard.
Mounting / Racking — The aluminium framework that holds panels onto your roof. Cheap racking is a common cost-cutting trick that surfaces years later as leaks, lifted panels, or warranty disputes — it pays to know the brand being quoted.
Orientation — Which compass direction your panels face. Combined with tilt and shading, it’s the single biggest determinant of how much power your system actually produces.
Shading — Anything that blocks sunlight from reaching your panels — trees, chimneys, vents, neighbouring buildings, even other panels. Shading on a single panel can drag down a whole string in a string inverter setup, which is why shaded roofs often justify microinverters or optimisers.
Single-phase vs Three-phase — How many “live” wires bring power into your home. Most older Australian homes are single-phase; many newer or larger ones are three-phase. Three-phase homes can usually have larger systems and higher export limits than single-phase ones on the same network.
Switchboard upgrade — Replacement or expansion of your home’s main electrical board to accommodate a solar or battery install. A frequent surprise cost on quotes that haven’t included it up front, especially in older homes.
Tilt — The angle of the panels relative to horizontal. The optimal tilt roughly equals your latitude, but in practice most residential panels just sit flush to the existing roof pitch.
Generation, use & export
Clipping — When the panels are producing more DC power than the inverter can convert, and the excess is “clipped” and lost. A small amount of clipping is normal and even economically optimal in deliberately oversized systems, but excessive clipping signals an undersized inverter.
Consumption monitor / CT clamp — A small device clipped around the cables in your switchboard that measures how much electricity your home is using in real time. Without one, your monitoring app can only show solar production — not how much of it you’re actually self-consuming.
Curtailment — When your inverter is forced by the grid operator to reduce or stop exporting, usually because the local network is at capacity. Increasingly common in solar-saturated suburbs, and the main driver behind the shift toward dynamic export limits.
Export limit — The maximum power your system is allowed to push back into the grid, set by your DNSP. Common limits are 5kW per phase, but many networks now apply lower static limits or dynamic ones that vary throughout the day.
Feed-in Tariff (FiT) — The rate your retailer pays you for electricity you export to the grid, in cents per kWh. FiTs have fallen dramatically — from 40–60c/kWh a decade ago to 4–7c/kWh in many plans today — which is the main reason batteries make more financial sense than they used to.
Self-consumption — The portion of your solar generation that you use directly in your home rather than exporting. With low feed-in tariffs and high retail prices, every kWh of self-consumption is worth far more than every kWh exported, which is why behaviour and battery sizing matter so much.
Solar diverter — A device that sends excess solar power to a specific high-energy load (almost always the electric hot water tank) instead of exporting it. A cheaper alternative to a battery for households whose biggest controllable load is hot water.
Time of Use (TOU) tariff — An electricity plan where the price per kWh changes by time of day — typically cheaper overnight, more expensive in the evening peak. TOU plans change the maths on batteries significantly, because they reward storing midday solar to use during the evening peak.
Rebates, regulation & paperwork
AS/NZS standards — Australian/New Zealand technical standards that solar and battery installs must comply with. The two most important for residential solar are AS/NZS 5033 (PV array installation) and AS/NZS 4777 (grid-connected inverters).
CEC (Clean Energy Council) — The industry body that accredits solar installers and approves products for use in Australia. Both your installer and the equipment they use must be CEC-approved for your system to qualify for the federal rebate.
CER (Clean Energy Regulator) — The federal government body that runs the STC scheme and oversees compliance. Effectively, the CER is the agency behind the federal solar rebate.
DNSP (Distribution Network Service Provider) — The company that owns and operates the poles, wires, and substations in your area — Ausgrid, Endeavour, Energex, Western Power, and so on. Your DNSP, not your retailer, sets your export limit and approves your grid connection.
Federal solar rebate — The everyday name for the discount on your system funded by STCs. It scales with system size and falls each year as the deeming period shrinks; it’s currently scheduled to end in 2030.
Cheaper Home Batteries Program — The federal battery rebate, which provides a discount on installed home batteries through the STC framework. Eligibility, value per kWh, and the list of approved products change over time — always check the current rules with your installer or the CER directly. (Worth verifying the exact wording before publishing — program parameters update regularly.)
Pre-approval — Permission from your DNSP for a specific solar or battery system to be installed and connected to the grid. Required before installation on most networks, and approval may come back with conditions attached (lower export limit, single-phase restriction, etc.).
STCs (Small-scale Technology Certificates) — The mechanism behind the federal solar rebate. Each STC represents 1MWh of expected generation over a deeming period, and your installer takes the certificates in exchange for an upfront discount on your system. The “rebate” is essentially the dollar value of those STCs.
Warranties
Performance warranty — A panel manufacturer’s guarantee about how much output your panels will still be producing after a set period — typically 25-30 years and 85-90% of original output. Distinct from the product warranty.
Product warranty — A manufacturer’s guarantee that the equipment itself will be free from defects for a set number of years. Panel product warranties are typically 12-30 years, inverter product warranties 5-10 years, and battery product warranties around 10 years.
Workmanship warranty — Your installer’s guarantee on the install itself — racking, wiring, weatherproofing, labour. Often the shortest of the three warranties (typically 2-10 years), but in many ways the most important, because installation faults are the most common source of problems.
