Starting out on a low budget - DIY Solar Power

You don't have to go 100% solar right from the outset. It is very expensive to purchase a complete system that will provide all your electricity needs. And if you're doing it entirely yourself, especially for off-grid standalone systems, you may not be elegible for any government subsidies. Government rebates only apply to professionally installed systems, and usually have to be certified to the applicable government schemes.

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You don't have to go straight to this immediately.
Start Small!

Start Small

Although you may be thinking of investing in a large solar PV system to go from 0% to 100% renewable energy in one hit, your main limiting factor could be a lack of funds. Having said that, it is quite common for many installations to start small and grow over time as the owner can afford more and more components.

How small is 'small'? It could be as simple as powering a few high-efficiency LED lights for night time lighting. Or enough to run a small power tool for a few minutes a day. Or even charge your laptop computer.

Components to start out with

Your starting system should not cost more than approximately $600 to $700. With this budget, you can comfortably purchase and assemble a system powerful enough to provide over 1 kWh of energy per week.

The basic components required are:

The 80 watt module should be enough to fully recharge the battery on a typical day with at least an hour or two of sunshine. The charge controller is rated high enough to handle the power outout of the panel, which is typically 4.5 amps for 80W panels.

The 100 AH battery stores enough energy to allow the use of:

The charge controller:

The inverter:

Other considerations:

Assembling / installing the system

A basic solar power system such as this will take at least a day to assemble. It could be done in a couple of hours, but rushing the process is definitely not recommended unless you are very experienced and have drawn up precise plans. Rushing the installation could lead to costly mistakes, especially when a high capacity battery is involved, which is capable of delivering hundreds of amps of current if accidentally short circuited.

Before you go out and purchase the ancillary items, you should make some measurements. The battery should be stored in a location protected from high heat and freezing temperatures. Calculate the distance the cabling needs to be so it can comfortably reach the panels on your roof to the battery. Your charge controller can be co-located with the battery. The power cables running from the panels to your battery need to be protected. If you cannot run them down the wall cavity, consider running them in conduit.

It pays to spend some time and effort acquiring and testing each component. For example, after purchase of the solar panel module, you will want to test its open circuit voltage and short circuit current to ensure it is within the specifications. After you have purchased the battery and charge controller, you should test them along with the solar panel to make sure they are functioning.

The solar panel is the most critical. It needs to be mounted on a angled (pitched) roof, on either a northern or southern facing roof area (as appropriate for your geographic location). If your home does not have such a roof space, you will not reap the full benefits of the panel. The ideal setup would be such that the sun is exactly perpindicular to your panel at midday - this is when the panel will be producing its peak output.

The panel needs to be secured well, idealy with a suitable racking system. For the cost conscious DIYer, a simple frame can be built out of treated timber. Hooks can be made of aluminium strips to secure them onto the tiles and also to hold the solar panel onto the frame. A fully aluminium racking system is highly recommended in the long term, because timber can rot over time, resulting in your expensive solar panel falling off the roof. If you do use timber, it should be treated with weatherproof paint or varnish to minimise rotting. They should also be inspected every few months to ensure their integrity.

Using the system

Once installed, the charging process is fully automatic, thanks to the charge controller. If you don't use power for more than a few days, the energy collected by the solar panel will not be stored because the battery is already full (and the charge controller has effectively disconnected the panel from the battery). On the other hand, if in the long term, you use too much energy from the battery than can be replenished by the panel, it will be in a chronically discharged state and the battery will deteriorate.

You will need to carefully monitor the battery voltage if you plan to run heavy loads. Don't let the battery voltage drop to less than 11 volts. This voltage should be measured after the battery has been at rest for at least one hour.

Your inverter should be connected directly to the battery, using heavy guage wiring to prevent loss of energy due to heating of the wire. A 600 watt inverter supplying a full load can use up to 50 amps from the battery.

Payoff / settling in period

Now that your 'mini' solar system is functional, you will probably want to make use of it for a good few months. During this time, you can evaluate its suitability for your energy needs.

Your payoff period or return on investment can vary. If it is for powering infrequently used power tools or appliances, the impact on your electricity bill could be minimal (e.g. $10 to $20 per year). On the other hand, if you install DC LED lighting for frequently inhabited rooms in your home and use them every night, your savings could be more significant (e.g. $50 to $100 per year).

Once you have decided on the feasibility of the solar system, you can think about upgrading or expanding it to allow more appliances to be run, thereby increasing the savings on your electriticy bill.

Expanding / Upgrading the system

As with many other addictions, once you're hooked onto renewable solar energy, your desire for more will be ever increasing. Fortunately, it is simple to expand this system. You can expand any part of this system; the parts you expand or upgrade depend on your usage patterns (and available money!)

If you find you are consuming more power than is provided by the panels (i.e. the battery is chronically discharged), you can purchase more panels. With each panel you purchase, you purchase another charge controller to go with it. Each panel should be connected to its own 6A charge controller, and you connect the outputs of the controllers in parallel to the battery. This will double the charge current. A 100AH battery can accept up to 25 amps of charge current, so you can have up to 4 more panels and charge controllers (of the 6 amp variety).

Alternatively, you can upgrade your charge controller entirely. There are many high-current, sophisticated charge controllers on the market, with status LEDs and LCD displays. A typical 20 amp charge controller costs about $130. With this charge controller, you can connect the solar panels in parallel.

If you find that you only need to occassionally use high load appliances, such as power tools, you will find the battery is always always full, with collected solar energy wasted. In this case, you can buy another battery to connect in parallel with your existing battery. This effectively doubles your 'energy bucket', so you can run your power tools for longer.

Unfortunately, if you need more wattage from your inverter, you will need to buy another higher capacity one to replace your old one. It is not possible to connect inverters in parallel to get more wattage. Having said that, you can keep your original inverter to run other lighter loads.

Up to a point, you may find the need to upgrade the cables connecting the solar panels to the charge controller. If you have many panels connected in parallel (e.g. 4 x 80W panels = 18 amps), the available current may be limited by your power cable. If your power cable is not rated to handle the current, it will heat up, causing energy losses. In the worst scenario, your cable insulation will melt, causing a short circuit, leading to a fire.


A small-scale, budget system is achievable, and you may well see some benefit. In fact, it is a great stepping stone towards a much larger solar power system.

This article only scratches the surface, and our other articles on each specific topic will improve your understanding of larger solar power systems and solar powe in general, even if you only intend on keeping it small. Hopefully you will apreciate the many aspects of solar power and go onto implementing larger system.


Dave, Tue, 15 Oct 2013 10:30 pm: Reply
Nice post. I appreciated the honesty in the times. Most people tend to lie about what they can do with small setups. I learned it takes a lot of solar collectors and right wire angle and battery and proper Mppt controller to really get out most for setup.

Please join us at below link in fb and post more great info. Thanks for great article.

Marcelo Monteiro - ELLO GROUP, Tue, 07 Apr 2015 04:14 am: Reply

We need price and delivery time for frequency inverters for solar panels 1 kV / 3kV.

Best regards,

Marcelo Monteiro

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