Solar Power System General Information

Will you need a regulator?
Yes, if you are dealing with large panels, you will generally need a regulator. Generally if your solar panel can fully charge your batteries in a day or two then you will definitely need a regulator. A power regulator takes the power from your solar panels and regulates the feed into your batteries which can be used at night or when there is no power coming from the panels. The prime role of the regulator is to make sure the batteries are not overcharged. Many regulators also prevent your batteries from becoming too discharged and will prolong the life of your batteries.

Some circumstances when you would not need a regulator are when your system has no battery or where the solar panel or if it is designed to slowly charge a large battery. Some systems with no battery might include a solar powered water pump in rural areas which only pumps water during the day, or as used in my campervan, solar powered air fans to ventilate the area during the day.

One important thing to note about regulators. Some are 'night light' regulators. They will only switch on power to a load when the incoming power is low, such as at night. These are good for controlling lights at night, but no good for use in alternative energy applications.

What sort of batteries should I use?
Deep cycle batteries will normally suit your system best. The capacity of the batteries will depend on what you want to power. I would suggest that you do a bit of research on solar panels and deep cycle batteries but I can suggest this: All research I have done has suggested that your battery should not be of too much capacity that your solar panels can not recharge them properly after being discharged over night. Flat or low charged batteries will not last as long as fully charged batteries. Regularly flattening the battery will dramatically shorten it’s life. A low voltage cut off or a regulator with built in low voltage cut off is a must and will save you money and inconvenience in the long run.

To size the solar panels large enough to recharge a battery bank (this is kind of a reverse way to calculate. Usually the Solar panels are purchased first and then the batteries sized to fit the panels): determine the battery capacity in amphrs x 12/5 = max solar watts needed.

How can I get more power out of my panels?
It is all done with mirrors. Literally, reflect more light on to the panels. If you can set up reflectors that reflect morning and / or evening light on to your panels you will get more power out of them. You might not want to do this during the hotter parts of the day, but certainly a few sheets of polished metal may be a cheaper alternative to buying extra panels. I’ve seen it done on a small scale, and read of it being done on a larger scale. Don’t expect miracles though. Twice as much light will not equal twice as much power. Also, I think there would be a limit to how much extra light you could reflect on to a panel before it became a solar furnace and went up I smoke.

Know your product - Solar panel manufacturers.
Here are a number of companies that I have seen who have manufactured solar panels. Remember when shopping for solar panels, always look for the lowest negative tolerance rating possible and the highest efficiency rating!

Uni-Solar. (3% Negative Tolerance)
Uni-Solar panels are manufactured in Mexico and California. Their panels are typically larger than most other panels of the same wattage. The Uni-Solar panels are also well known for their shade resistance through the use of bypass diodes. In plain language, if part of the panel is in shade the unshaded portion of the panel is better able to pass along it’s power than pretty much all other brands of solar panel. They also perform better than most panels as they get hotter. Almost all other panels become less productive in the heat. This makes them well suited for mounting on campervans, motor homes and caravans. The Uni-Solar panels are also pretty tough. I’ve read reliable stories and seen pictures of Uni-Solar panels that have come off car roof and still been useable.

Uni-Solar produce rigid panels and flexible ones. That’s right, solar panels you can roll up. The large rigid 64 Watt solar panels usually sell for $590-$640 (plus shipping), depending on demand and availability. There has been a supply issue with them in the past but I think that has been resolved. Smaller flexible panels are more expensive per watt. These are the only large panels that I would recommend paying more than $10 per watt on. The flexible panels are used a lot for marine use such as sailing boats as they are very weather proof.

My personal experience with the Uni-Solar panels are that they have been reliable, easy to maintain and produce good useable power. They are also easy to wire up, having a large junction box for easy wiring. I have had no issues with them. They work fine.

Sharp. (5% Negative Tolerance)
I think that up until recently Sharp was the largest manufacturer of solar panels in the world. Their technology is mature, as they have had a lot of experience with making solar panels. Generally Sharp make panels in the 80-120 Watt range, with a few smaller ones. They make rigid panels only. Their panels are easily recognizable as they tend to have square cells that cover the entire panel surface.

I have brought a 55 Watt Sharp panel in the past and had no problems with it. I can certainly recommend them. Most Sharp panels are manufactured and used in Germany where there are some pretty impressive solar power stations.

SolarWorld (3% Negative Tolerance)
Another good manufacturer and one of the best tolerance ratings in the market

Reliagen (3% Negative Tolerance)
A great manufacturer with the best tolerance rating on the market and the best efficiency rating!

Suntech (3% Negative Tolerance)
Suntech is a relatively new beginner in solar power manufacturing. They are a joint Australian - Chinese company created by a dual nationality Chinese-Australian, DR Zhengrong Shi. Although they are new, their solar panels are top notch, and they offer the standard 20 year guarantee on their panels. They produce rigid panels from 2-165 watts . I have an 80 Watt Suntech panel mounted on my campervan. It has performed well, and I have had no issues at all with it in over a year.

BP (5-9% Negative Tolerance)
BP (British Petroleum) is one of the oldest producers of solar panels. Some of their panels have been in use in Australia for 20 years or more now. They tend to produce high wattage solar panels between 80-220 watts. Their panels still tend to have a bit of a retro look with lots of small round photo voltaic solar cells. I have no experience using these panels but I know people who have, and they have not had problems with them.

Kyocera (5% Negative Tolerance)
Kyocera is the world’s largest manufacturer. They have good quality, effiency rating and warranty. Can’t go wrong here.

Mitsubishi (3% Negative Tolerance)
Another great name and product. Can’t go wrong here.

There are many others, but one of the biggest factors to keep in mind is your application. A small remote application for the mountains is a different require than a home large solar power system, and as the quality goes up so does the price. Also, some manufacturers or providers will only sell particular panels in large quantities. So you may have to settle for a lesser quality for your application.

What about these double sided space technology solar panels?
I’ve seen a few of these on eBay recently. I don’t own one, I don’t know anyone that does. However, logic suggests that unless you have a set up that reflects light on to both sides of them, they will only get light on one side. In truth I expect that all solar panels that were mounted in glass without a non transparent backing would work this way. Until I test one of these I am a bit sceptical. If the panel is mounted in glass with no backing it may be more fragile than a normal panel. Still if it comes with a 20 year warranty, maybe it is worth a try, provided the company that makes them will be around in 20 years.

Other forms of alternative / remote area power.
Wind generators.
These are generally new to the market but are coming down in price. Wind turbines and wind generators generally will produce more power than solar panels. Typical small systems will generate about 200 watts of power. That is more than my 4 solar panels put together. These units are small, light weight and reasonably easy to set up. I have seen one of these set up as a demo model. It certainly managed to produce a lot of power. One problem with them though is that unlike solar panels they have moving parts and will require maintenance.

Wind generators come in much larger sizes though. 24 volt 700 watt models can be brought for under $1000. This represents much better value for money if the wind generator is able to provide power at a steady rate. Wind generators will not generate power if there is no wind, but unlike solar panels, they can generate power at night.

Petrol / Diesel Generators.
You might think that generators are not exactly alternative power, but they certainly are useful remote area power. You should not rule them out. Particularly as a small generator could provide you with all your power needs. A small generator of reasonable quality could cost less than $200. Considering that four solar panels might cost you about $2500 that would leave a lot of money left over for fuel to run the generator. Generators however usually don’t last 20 years. They require maintenance, refuelling, repairs and eventual replacement. They are also noisy. However, they provide almost the only reliable guarantee of power when you