Solar Andalucía

Solar Survival Manual

(Article from The Olive Press Sept. 2008)
Winter is closing in on us. Autumns first series of overcast days has all ready taken it’s toll on the solar homes of Southern Spain, and we know that there is yet more to come. Previous winter calls to needy solar clients, urges us to address a few points on the daily usage of solar systems.

Instead of over exploiting the limited capacity of your solar system, or spending your hard earned Euro on more gear, you might achieve some surprising results with a slight change of habit. Quite often it is possible to reduce your energy consumption at night, when all you have is the stored energy.
Batteries are the weak link in all solar systems. It is the only element that wears, and they will need replacement after a number of years. How long depends on battery size and quality but also how you treat them.
Here in lies the key to good solar economy! The less you have to discharge each night, the longer service life you will get.

Try to change the timing of your power usage for big loads to the afternoon, and conserve the stored energy in the battery bank for minor uses at night.
By using your system extensively in the afternoon, you utilize the panels to their full potential. The solar regulator, which will slow down the charge current before 100% charge is reached, will allow more energy to flow through your system this way. In fact most solar regulators will top up your battery store much quicker if you “tease” them with a load, after 80% charge is reached.
This charge level is usually reached after about 3 hours of full sun on your panels, if your system is set up properly.

An example: When do you turn on the washing machine? In the afternoon of course, when the batteries are fully charged, and all that good energy in your panels has nowhere to go. It’s for free then!
Being away for work is no excuse, when you can buy a cheap timer to start the washing at the right time.
Further more, if you coil up about 200 ft. of cheap black irrigation tube somewhere between the water supply and the washing machine, chances are that your wash will be a warm one!!!
Powered by the low winter sun, water temperatures can reach as high as 30 to 35 degrees Celsius in a black tube placed on a south sloped terrace in the afternoon, and that’s for free too!

Other tasks that consume a lot could be usage of power tools or downloading big data files, like TV programmes, From the Internet.
Turn on your Internet connection mid morning and start downloading. Chances are that your batteries will be full before sunset. Don’t wait till night time with this! Preserve the energy stored in your batteries for what’s important after dark such as light (use LED’s now available in warm white, you can actually live with), Television (a reasonably sized LCD screen is between 50 and 85W).
Use a Laptop Computer!!! (usually 50W). A stationary desktop computer is hungry (commonly 400W) so get rid of it!
If you like to play music, use the laptop for this as well. Small satellite desktop speakers with a hidden sub woofer (bass speaker) gives surprisingly good audio quality for little energy costs.

By changing your habit you will soon realise, that life is just as good and full of possibilities on a medium sized solar system, as on the grid.

Some items you just have to part with.
Appliances like electric kettles, toasters, the abdominal hair dryer, massive big Televisions or Stereos produce too big a constant load on your batteries (unless you have 2500 – 3000 Amp hours of storage).
All appliances has a sticker attached on them telling what Wattage (power consumption) they consume. At night time a constant load of more than 100-150 Watts will inflict a massive drain on batteries smaller than 1000 Ah.

It is imperative that you understand the following, although a bit technical it’s the essence of solar maintenance.
Batteries are chemical storage units. That means that they are a bit slow in response to big loads.
The latency (delay) of the chemical process in the batteries, when you turn on something ferocious, will often result in double or more drainage of your stored energy, than the stated consumption of the appliance!
You can compare it with running a hot tap from a water storage. If you run a trickle, the water remains hot for a long time, but if you open up the flood gates it will be cold pretty soon.

Never cut corners when you invest in batteries!
It is logical that a larger battery bank deals more easily with bigger loads than an inferior bank. It is therefore also deductible that this part of your solar system has to be of good quality and of sufficient size. We are all prone to under estimating our consumption, but the price you will pay for killing an inferior battery bank prematurely is devastating. It’s tempting to say that you might as well have thrown your money out of the window. Battery banks are usually around 1/3 of the full system price – including the installation, so it is important to get this right.

Seen in this light, even a “triple A” high efficiency fridge can severely drain your batteries at night, and cost you the untimely and pricey renewal of your battery store.
The fact is that modern fridges, although economical over 24 hours, tend to make an excessive load on your batteries when the big compressors kick in.
Change to a gas propelled fridge instead. Either Spanish made Taver or the Brazilian made Butsir is available here in Andalusia. The Butsir looks and works just as good as a normal electric fridge, and then they are completely silent! No humming to disturb your rural retreat.

Your solar system is a reliable constant slow source of energy. Slow means it takes time to reproduce what you consume. You can’t take more energy out than what is being stored. Try to avoid discharging you batteries below 50% capacity, this dramatically prolongs the life of your battery store. That being said, it is also a fact that we are situated in one of the best solar regions on Earth. In Southern Spain you can live on half the size of panels, than you would have needed in the North of Europe, giving you plenty of energy to a modern lifestyle. All it takes is a bit of planning.

Finally as a solar user, you are one step ahead of the grid tied community. It is foreseeable that the hour of Truth will dawn on the high energy consuming Grid very soon. Electric power is precious and increasingly expensive.

Jim Skau