Solar Installation Component Glossary

Here's a quick rundown on parts used in a variety of solar installations and what they are used for:

Solar Battery - to store energy for later use

Solar Panels - Framed cells with a series of silicone wafers which generate DC voltage used to charge batteries

Solar Array - A collection of solar panels connected together to provide DC voltage

Frame rails - Support structure used to build a platform to place solar panels on. They can be mounted on walls, roofs, ground, tilted frame rails.

Solar Controller - (also called Charge Controller) connects the solar panels to the battery bank. The cheaper version use PWM (Pulse Width Modulated), the better versions use MPPT (Maximum Power Point Tracking) to harness the variable energy from the sun during a day and convert it into the correct charge voltage which is put into the batteries.

String Inverter - is really a solar controller that you'd use connected to the national grid across a larger array at a residential voltage up to 600VAC. In commercial installations, the string inverter can be up to 1000VAC. These higher voltages allow the solar panels to be connected in series to add voltage while the current remains the same as that of just 1 panel. These units only convert DC energy from solar to AC and connect to your main switch board. If the mains power stops for any reason these inverters also stop working for safety reasons.

Grid-Tie or Grid-Tied or Grid Connected - means a system connected your onsite power generation to the national grid.

Off-Grid - means your system is stand-alone with no national grid network attached. Typically used in remote locations.

Hybrid Inverter - allows a string inverter which only generates AC power from DC solar, to also be able to use the DC power from solar to charge a battery bank.

DC Coupled System - Uses the DC power from solar panels to be put straight into batteries with only the MPPT controller ensuring the voltages are correct to charge the batteries and minimilising conversion inefficencies. It then uses the stored DC energy in batteries to pass through an AC inverter to power the AC load. It can also export this power to the national grid once its in AC if you configured your system to do so.

AC Coupled System - Inverts the DC power from solar panels into AC and supplies the main switchboard and any loads attached. When there is excess power from solar available it can either export the AC power to the national grid. It could also convert the AC power back into DC power and charge a battery bank. When the stored power is needed it converts the DC back to AC to supply the main switch board.

Zero Export - this is when the national grid carrier doesn't want you to export any of your excess power back to the grid. Many regions in NZ now have a 5kw Max. export limit managed by Transpower and many power retailers only pay back a certain number of units of energy back to the grid per day.

Fuse - Fuses need to be held in place so use some form of fuse holder, they have different current ratings and each rating is typically a different colour. So if your blue fuse blows then you need another blue fuse to replace it. There are many different style of fuses from Class T, NH, Auto Blades, Maxi Fuses, Midi Fuses, Mega Fuses, ANL or FBT tag Fuses. The right type of fuse should be used for each instance.

Circuit Breakers - These are like a fuse, used to protect your circuits from over current. A fuse breaks and needs replacing but a circuit breaker can be reset and used again. There are 3 types of circuit breakers, automatic (which disconnect when blown but reconnect once they have cooled down). Manual Reset meaning it blows (opens the circuit) if tripped, then requires manual switching on to reactivate the circuit. Lastly PTT (Push to Trip) You can manually open the circuit and then re-close the circuit just like using a switch but with current protection builtin. Variations include double pole which means a breaker for the negative cable and a pole for the positive cable so total electrical isolation is achieved. There are also polarised and non-polarised, the later meaning they do not have an inward direction or outward direction in which the energy should flow from battery to loads.

Charger - A device that provides voltage above the open circuit voltage of a battery. This could be a solar controller, mains powered charger or DC power charger (DC to DC charger). Modern-day chargers would have charge profiles and can be set to best match the charge voltages required by the batteries manufacturer.

Cables - These are used to connect all the components on the DC circuit, normally multi-string copper cable which might also be required to be tin-coated. This cable is measured by its cross-section in mm squared. The number of strands is important for flexibility and ultimately affects its maximum current capacity. The insulation is also important, many require double insulated where there might be a coloured (blue or red) plastic around the copper, then each colour, if the cable is 2 core (a red and blue together), is then moulded inside an outer insulation like black for instance as seen in twin-core solar cable. They can also be built to be circular when cut cross-section, cheaper and more popular is a figure 8 shape when you look onto the end of the cut cable. This outer layer might also include a high content of silicone so the cable slides easily during installation. It can also be manufactured to include a UV protective material so it doesn't break down in sunlight. This outer is referred to as PV1. AC power cables are normally solid core cables in 1.5mm or 2 or 2.5mm2 and are either 2 or 3 core TPS in white or purple outer colour. With the Life, Earth & Neutral wires inside (Red/Brown, Black/Blue, Green/yellow)

Solar Installation Guide

Many people are interested in renewable energy and are installing it themselves. Here's a quick guide on electrical components and their connection order to install.

1. The battery, it's the heart of the system. It's where energy is stored, it's charged via a solar panel and powers equipment from devices attached to its terminals. So this is always the first place to start. You should be using fuses on all cables which would have a direct connection to power. If you also have a switch panel you should include 1 large fuse directly off the battery to the switch panel, then smaller fuses for each circuit running of each switch.

2. Charging circuit, this normally consists of 2 scenarios, either a solar panel and solar controller, or a mains powered battery charger. Both are OK to use at the same time to charge up a flat battery.

For Solar Panels connect the battery to the solar regulator first. Connect the battery neg to the controller battery neg. input/output, then connect the pos. terminal of the battery to the battery input/output. (we say input/output as you might be using the solar controller devices outputs which are normally indicated as a lightbulb to power your devices). If you have any equipment that exceeds the current rating of the solar controller you shouldn't use these lightbulb outputs but instead connect your discharging equipment directly to the battery terminals so you don't overload the controller).

If you are connecting a mains charger that can be connected to either a generator or a mains power source you just need to connect the positive and negative terminals to the battery. If it's a permanent installation it would be best to use eyelets and not the alligator clips as they can come off easily.

Now for the solar panel - a 36 cell panel outputs around 17-18 volts which is too high a voltage to connect directly to a panel so it needs to be connected to a solar controller. It should also be fused and switched so you can turn it off when necessary. Connect the negative terminal first and then the positive terminal.

With that done your solar controller should have the solar panel input indicating its working and the battery being connected will be charging. If the battery is already fully charged then there won't be must current flowing and it might only indicate a voltage up to 13.6 volts but that's OK. A fully charged battery doesn't need a charge. If however, the battery was flat, let's say the voltage was only 10 volts, it will take many hours, maybe days to get the voltage up to 13.6 volts. That's not uncommon if using one small panel on one large battery. Just let it do its thing until a full charge has been done prior to you discharging energy from the battery.

Reconditioning a battery?

CTEK chargers have 2 conditioning charge states.

The first is the desulphation stage 1, its a pulse charge but is only used if the 12 volts open circuit voltage is below 10 volts when first connected to the charger. The idea behind this type of pulsing charge is to slowly bring the battery back up into normal charging conditions by slowly bringing the voltage up and not by overheating the battery or ramming large current into plates not wanting to operate outside normal conditions.

The second conditioning state is a mode selected by the users on the following models. MXS 5.0, MXS 10, PRO15, PRO25, and other professional series chargers. Mode 5 is added to the otherwise 7 stage charger to increase the voltage to 15.8v (on a 12 volt battery) and maintain a low absorption charge to ensure the battery cells are equalised and that every possible area of the plate is fully saturated with energy. Much like leaving a sponge in water to ensure it soaks up every last little piece of water it can.

Vehicle's electrical systems are designed to operate within industry standards which on 12 volt systems includes voltages up to 16 volts. In fact, we know of many vehicles that peak at over 17 volts but still use 12 volt batteries. In general anything above 2.45 volts per cell (14.7 volts) is a maximum charge rate but for short periods of time a higher voltage helps desulphate lead crystal build-up and can be very helpful to extend batteries usable life. It can also be the treatment that pushes a battery too far and it fails from drying out so the frequency of use should be managed.

Keep in mind a recondition charge is only performed once on a battery when the battery is stored for a long period of time as the stage is only initiated the once.

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