Solar Panel

The term solar panel is used colloquially for a photo-voltaic (PV) module. A PV module is an assembly of photo-voltaic cells mounted in a framework for installation. Photo-voltaic cells use sunlight as a source of energy and generate direct current electricity. A collection of PV modules is called a PV Panel, and a system of Panels is an Array. Arrays of a photovoltaic system supply solar electricity to electrical equipment.

Charge Controller

The term solar panel is used colloquially for a photo-voltaic (PV) module. A PV module is an assembly of photo-voltaic cells mounted in a framework for installation. Photo-voltaic cells A charge controller, charge regulator or battery regulator limits the rate at which electric current is added to or drawn from electric batteries. It prevents overcharging and may protect against overvoltage, which can reduce battery performance or lifespan and may pose a safety risk. It may also prevent completely draining (“deep discharging”) a battery, or perform controlled discharges, depending on the battery technology, to protect battery life.


The term solar panel is used colloquially for a photo-voltaic (PV) module. A PV module is an assembly of photo-voltaic cells mounted in a framework for installation. Photo-voltaic cells Component of a solar panel system that converts the electricity generated by solar panels into a format that can be used to power your home.

Off Grid

ThCompletely disconnected from the electricity grid, with no access to utility-generated electricity. Homes that go off grid need to generate all of their electricity on-site.

Kilowatt-Hour (KWh)

Standard unit for electricity. In 2014, the average U.S. home used 911 kWh per month.

Photovoltaic (PV)

A type of device that generates electricity directly from sunlight. Solar panels are photovoltaic devices.

Power Rating

Represents the theoretical power output of a solar panel in ideal conditions. While power rating is a good indicator of quality, most solar panels don’t experience ideal conditions for more than a few moments.

Solar Panel Efficiency

Represents how well a solar panel converts sunlight into electricity. Most solar panels have 14 to 16 percent efficiency; high-efficiency panels are rated just above 20 percent.

Temperature Coefficient

Represents how well a solar panel can perform in high-heat conditions. As with all electronics, high heat can negatively affect solar panel performance.


The direction that your roof faces (in the context of solar). The azimuth is measured in degrees, representing the angle between your roof and true north.

Alternating Current (AC)

The type of current that is used in our homes and most transmission lines. Rather than just flowing in one direction, the current rapidly moves back and forth 50 times a second, which is the standard in the majority of countries. But most of the Americas, half of Japan, a couple of Koreas, Philippines, Saudi Arabia, Madagascar, and Liberia wiggle it back and forth 60 times a second.

Ampere (A)

The unit of electrical current which refers to the rate of flow of electricity. A normal Australian power point can supply 10 amperes. An electric stove will normally have a 32 ampere connection which means it can draw a lot more power than if it was plugged into a standard power point. In Australia ampere is almost always shortened to amp. The number of watts is equal to amperes multiplied by volts, so a 10 ampere power point at 240 volts can supply 2,400 watts.

Ampere-Hour (A·h Or A H Or Ah)

A current of one ampere produced for one hour. Lead-acid batteries used for home energy storage often have their capacity measured in ampere-hours. To determine its capacity in kilowatt-hours, multiply the ampere-hours by its voltage and then divide by 1,000. So a 100 ampere-hour 12 volt battery can output a maximum of 1.2 kilowatt-hours.


An anode is an electrode which current flows into. When a battery is discharging electrons flow from the cathode into the anode.


A collection of connected solar panels that work together which can range from 2 panels to over one million. Array is definitely not what killed Steve Irwin.


A specially constructed case containing potential chemical energy. When a chemical reaction occurs electricity is generated and can be used to do work. In disposable batteries the chemical reaction cannot be easily reversed, so avoid using them. In rechargeable batteries the chemical reaction can be reversed by supplying electrical energy. (Or in some rare cases sticking part of the battery in a really hot oven or other weird behaviour ).

Battery Capacity

The total amount of electrical energy a battery can provide before it is completely discharged. Battery capacity is often higher than usable capacity because many types of batteries will be damaged if they are completely discharged.

Battery Case

The tough protective case that protects the battery cell or cells inside. It is part of the battery and doesn’t need to be purchased separately

Battery Cell

A battery can be made up of many individual units called cells. Or a battery can be a single cell, such as the small batteries you might put in a remote control or toy. Very rarely you will come across a person who will insist that a single cell cannot be referred to as a battery, but that person is a dick and can be safely ignored.

Battery Cycle Life

This is the number of times a battery can be fully discharged before it becomes so degraded it can only operate at 80% of its original capacity. Because a full discharge is very hard on most types of batteries the number of cycles that are typically given for home energy storage systems are not for 100% discharges and will usually be for 80-90% depth of discharge instead.

Battery Enclosure

A cabinet or structure that holds batteries. This is important for lead-acid batteries used for home energy storage as they can take up a lot of space, require a lot of cabling, and both children and batteries operate better when kept separate from each other. Modern home energy storage systems normally do not require an enclosure as they are designed to be less dangerous and less infested with cabling.

Battery Management System (BMS)

The software and electronics that control how a battery charges and discharges. Some batteries come with a built in BMS. This is good, because the BMS can act as a ‘gatekeeper’ to the battery and stop the battery inverter doing things that would damage the battery, such as charging/discharging too fast or too much. Batteries without a BMS are trusting the battery inverter not to do anything stupid.


This is the electrode in a battery which positively charged cations move towards and negatively charged anions moves away from.


Putting energy into a battery. Technically we should say energising instead of charging because the amount of charge in the battery is always the same, it is only the type of charge that changes, and what matters is how much usable energy there is in the battery that can do work for you. But no one really cares about this, so go ahead and charge away.


A loop that electricity travels through. A circuit can have one or many electrical components on it.


A flow of electricity. There are are two types. Direct current (DC) where electricity flows through a conductor in one direction. And alternating current (AC) where electricity rapidly flows back and forth in a conductor.