| Before we installed our system, I looked | | | | below) which is the single most expensive piece |
| everywhere for tips and knowledge that would | | | | of kit in your whole system. |
| help us avoid making the wrong choices. Three | | | | If the voltage coming out of your generator is |
| years of misery have gone by before we have a | | | | too high it will blow up your inverter, which cost |
| reasonable working system. We live in Spain. | | | | us 5,000, and the guarantee will not be valid |
| There is a grant for installation of off-grid power | | | | unless you are really lucky, as we were, twice! |
| which means battery-backed electrical systems. | | | | So, my recommendation to you is not to wire |
| The type of solar panels that heat your water | | | | the generator into your inverter but to use a |
| are quite different and we can consider those on | | | | stand-alone battery charger. Ours was designed |
| another day. | | | | to recharge a fork-lift truck so it knows to turn |
| There is quite a lot of help on the web for those | | | | itself off when the batteries are full, although I |
| seeking "normal" electric power when they live, as | | | | can't imagine anyone using a generator for that |
| we do, miles away from any mains electric | | | | long. |
| transmission line. But that help tends to be specific | | | | The inverter turns your DC battery-stored |
| to, say, windmills or PV panels, rather than | | | | electricity into AC voltage at 230v (or 120v in the |
| covering the whole layout and most of the | | | | USA) which means that ordinary machines that |
| articles are from the USA. Firstly, relevant only to | | | | you buy in the high-street shops will work. If your |
| Spain, there is a grant "subvencíon" from Prosol, | | | | generator is wired into your inverter the mains |
| in Andalucía, a government sponsored agency. | | | | type power produced by the generator can be |
| The grant was, in 2007, for 40% of your solar | | | | diverted into the house when not powering the |
| panel (PV) cost, it has dopped in 2009 to around | | | | batteries and, in our instance, this caused endless |
| 30% and you now need two sources of "green" | | | | small power surges as the inverter switched our |
| energy for instance solar panels and a wind | | | | electric supply between generator and battery, |
| turbine. | | | | another reason to use a stand-alone battery |
| These things matter, our total expenditure on | | | | charger. The inverter is a large and very heavy |
| stand-alone electricity has been around 24,000 | | | | box because, other than some delicate and |
| of which 8,000 has come back by way of | | | | complicated electronics, it contains a coil that |
| government subsidy grant. So, if you live in Spain | | | | actually converts your battery power to |
| (or anywhere where there is a government | | | | mains-type electricity. As stated above, it can be |
| subsidy) number one on you priority list is to be | | | | really expensive and for this reason some people |
| absolutely 100% sure that your supplier qualifies | | | | use more than one. Two small ones are far |
| for the grant. Although we eventually got ours, it | | | | cheaper than one large one but we opted for a |
| took three years of legal battles and our supplier | | | | single one that produces 5kw continuous (with a |
| has now gone out of business. Our neighbours | | | | maximum load of 10kw) on the basis that 5kw is |
| (our nearest but they are 3km away) were much | | | | represented by the diswasher, washing machine |
| smarter, they only paid the (same) installer 60% | | | | and swimming pool pump running together so you |
| of the installation price and said they would pay | | | | don't want the whole system to overload when |
| the difference when their government grant | | | | the fridge cuts in. Ours is produced by Mastervolt |
| came through (it hasn´t). | | | | in Holland and they are such a joy to deal with, |
| OK, so you are smarter than us and you have | | | | thank you Mastervolt. However, many people |
| tied your supplier down to a really tight contract | | | | have a small inverter for the lighting circuit and a |
| which gives you your power but throws the | | | | larger one for the ring-main. |
| burden of reclaiming the government grants onto | | | | When our inverter went wrong last time, I |
| them. What are you going to order in the way of | | | | installed a 48v computer UPS (uninterruptable |
| off-grid electric power? Obviously, this depends on | | | | power suppy) in its place until it returned. This |
| where you live. If you don´t live somewhere | | | | cost me (second hand and without the battery, |
| with a resonable sunshine record, forget PV. Here | | | | I've got batteries) less than 100 and produced |
| in the sunniest part of Southern Spain (and | | | | around 2.5kw of perfect power. Luckily, I don't |
| we´ve had a horrid winter) we get around 12 | | | | really have to think about it but if I was starting |
| kilowatt hours per sunny day from our 2kw array | | | | over I might well have a bank of UPSs rather |
| of solar panels. What does this mean? This means | | | | than a single inverter, however you would need |
| that we have 12 x 170w panels on our roof which | | | | to wire the house differently as you cannot mix |
| generate (in perfect conditions) just over 2kw of | | | | the AC current from different sources. |
| power which goes into our batteries. The actual | | | | The next most important piece of kit (other than |
| power that they produce depends on the amount | | | | the panels) is your charge controller. Here, I can |
| of sunlight, the heat of the panels (they produce | | | | recommend the Outback MX60 (one of only |
| less electricity when they heat up, which they | | | | three names that I will recommend to you in this |
| naturally do in the sunshine), and the length of the | | | | article). The Outback takes the power from the |
| day. So, in winter the panels are cold, the day is | | | | solar panels and uses it to charge the batteries. |
| short and the sun can be dazzling. In summer the | | | | The MX60 is limited to 60 Amps output power |
| panels are hot, the sun is out for ages and the | | | | (unless you read the manual and work out how to |
| quality of light is often less good - hazy. | | | | get it up to 70) and volts x amps = watts |
| We alter the angle of the panels in the Spring and | | | | (power). Therefore in a 48v system power |
| Autumn because this gives us an extra 7% or | | | | output from the MX60 is twice what it is in a 24v |
| 150 watts of power by pointing the panels more | | | | system, and this could be another deciding factor |
| towards trajectory of the sun. In the winter, the | | | | for you in choice of voltage as for a 2kw panel |
| sun is low on the horizon, in the summer it goes | | | | array you would need two MX60s if you are on |
| almost right overhead. The angle we use is 25º | | | | 24v. There are three really clever features on the |
| in summer and 45º in winter. The panels MUST | | | | MX60, which is configurable for 12, 24 or 48v |
| point due (not magnetic) South. Amazingly, the | | | | output. Firstly, it will take a much higher input |
| amount of power produced in a day in the | | | | voltage than its output voltage (but only up to |
| summer or the winter is about the same. | | | | 130v maximum). This means that we have linked |
| The difference is that in the winter we don´t | | | | three 24v solar panels in series to produce a |
| use much power, only for lighting and the normal | | | | nominal 72v output and an effective output much |
| household machines. In summer the swimming | | | | higher, ours has peaked at 118v. The higher the |
| pool pump is on for four to six hours a day and | | | | voltage, the less power is lost in the wires |
| this really strains the system. I will come onto | | | | beween the panels and the batteries. As we have |
| batteries, inverters, charge controllers etc. later | | | | 12 panels, there are four sets of three with the |
| but I want a reader to understand what they can | | | | four sets linked in paralel. Then the MX60 benefits |
| achieve with a 20,000 spend on solar PV and | | | | from MPPT, maximum power point tracking, |
| wind electric. | | | | which wrings a little more power from those |
| When we first looked into this whole matter, | | | | expensive solar panels. Lastly, the MX60 comes |
| there were numerous blogs and websites that | | | | with an optional external thermometer which |
| told us that we had to save every ounce of | | | | attaches to a battery and it therefore alters the |
| energy or we would not be able to live a normal | | | | charging of your battery bank to optimise it for |
| life. The reality is that we run the washing | | | | temperature, thus extending the life of your |
| machine (but not tumble dryer), the dish washer, | | | | batteries. |
| the steam iron, the fridge-freezer, the electric | | | | Solar panels are a commodity and they are the |
| toaster, the Magimix, the breadmaker, the | | | | only things backed by a long guarantee. The |
| microwave, the de-humidifyer, the water | | | | Spanish government insists that they should be |
| pressure pump and (the worst culprit) the | | | | guaranteed to produce 80% of their rated output |
| swimming pool pump. So we live a normal life and | | | | after 25 years. The first set that we got were |
| we have no electricity from the grid. | | | | branded Suntaics, a German company who are |
| When we looked into the concept to begin with, | | | | among the least helpful people you could ever |
| websites told us that we couldn´t have fridges | | | | come across. These panels went wrong within six |
| or freezers or any form of electric-guzzler. Just | | | | months as connecting wires within them melted. |
| not true, you can use your hair dryer because | | | | My recommendation is to pay a little more and |
| it´s only on for 10 minutes and the big baddie is | | | | get a really well known brand from a company |
| the swimming pool pump which consumes the | | | | that will be around in 25 years to honour their |
| same amount but is on for hours. To sum up, for | | | | guarantee. Since installing ours into a frame that |
| an outlay of 16k (after the grant), you can | | | | hinges at the bottom to allow us to change the |
| have an electric system better than the mains (at | | | | angle at different times of the year, I need at |
| least in Spain where it is forever failing and | | | | least one other strong man to help me raise or |
| "browning out"). Here in Andalucia, the average | | | | lower them. My recommendation would be to |
| electric bill is 250 every two months to include | | | | mount the frame on a central pipe, like a scaffold |
| Winter Heating and Summer Cooling. This adds up | | | | tube, which could be rotated to change the angle |
| to around 1,500 a year, none of which is | | | | and would require very little effort compared to |
| payable for a PV system. This seems a realistic | | | | physically lifting the set of six panels which are |
| payback timescale to me of 10 to 12 years (or | | | | fitted in a single frame. |
| shorter if the price of electricity increases). | | | | Solar panels give off electricity, called photovoltaic |
| Before you buy, just be certain of all your costs. | | | | or PV, when they receive light and they can be |
| Your installer will be going through the normal | | | | wired together in series, as seen above, to |
| wholesale channels in Spain and you will be paying | | | | produce higher voltage. I know this may sound a |
| retail prices. Some items are so much cheaper | | | | little simple, but you can only charge your 48 volt |
| from the UK that, grant or not, you have to buy | | | | battery if you are inputting more than 48 volts. |
| them there and get them couriered to Spain. | | | | And remember that in its "absorbing" stage, your |
| ALWAYS check prices on eBay before you buy | | | | battery might get up to 60 volts before settling |
| anything. | | | | down and "floating" at 54 volts or so (this |
| Batteries. Assuming you have a largeish installation | | | | changes with the temperature and with the type |
| you will either be running a 24v or 48v system. | | | | of battery). Therefore, you can't charge a 48 volt |
| Which to choose? We have 48v which means 24 | | | | battery from a single 24 volt solar panel, you |
| x 2v batteries. A 24v system which had the | | | | need at least two wired together. Just to confuse |
| same battery capacity would have 12 batteries of | | | | you further, a 24v solar panel will produce up to |
| 2v but with each battery double the size. Why | | | | 40v or more depending of temerature and |
| would you choose one over the other? Well, my | | | | amount of sunlight! This concept is vital when we |
| opinion is that 48v is more elegant but there again | | | | consider the windmill. |
| there is more kit available for 24v. How on Earth | | | | We only have a windmill to qualify for the grant. |
| can you understand this? A four cylinder car | | | | Having said that, we wouldn't be without it now. It |
| engine is perfectly good but an eight cylinder is | | | | was cheap and manufactured by FuturEnergy |
| better, although more expensive. I don´t think it | | | | from the UK who are extremely helpful. You can |
| matters massively which you choose, 48v will | | | | get the whole thing from eBay for less than |
| cost you a little more so if you´re on a budget | | | | £1,000, windmill, charge controller, stop switch |
| go 24v but the difference isn´t huge. | | | | and dump loads for something that outputs a |
| Batteries. What is the only important thing about | | | | nominal 1kw (our solar panels are rated at 2kw |
| batteries? That they are NEVER discharged | | | | but rarely produce more than 1750w because |
| beyond their nominal value. So, we have 24 x 2 | | | | they produce less as they heat up). The |
| volt batteries making a nominal 48 volts. These | | | | FuturEnergy windmill outputs a nominal 48v, |
| batteries will actually charge up to around 60 | | | | another plus for choosing a 48v system. |
| volts, depending on temperature. This | | | | So when it blows a gale, normally when the sun is |
| "overcharging" is called "absorbing" and cleans the | | | | not shining, we don't have to use the generator |
| lead plates. After a couple of hours the charge | | | | to charge the batteries. However, most of the |
| controller will drop the voltage to around 54 volts | | | | time, the windmill is useless because the voltage it |
| which is called floating. If your batteries discharge | | | | produces depends on the speed at which it is |
| lower than their nominal value, 48 volts in our | | | | turning (I only found this out by disconnecting it |
| case, they will be ruined, meaning that they will | | | | from the batteries which you are not meant to |
| never be able to store a full charge again. Please | | | | do). If the batteries are normally at around 49 to |
| understand this it is the most important fact in all | | | | 50 volts at night or when there is no sun, which is |
| your solar power installation, if you learn nothing | | | | a "comfortable" level, then the windmill cannot |
| else from this, please remember to NEVER let | | | | charge them unless it is producing more than 49 |
| your batteries discharge below thier nominal | | | | volts. I haven't measured the wind speed at which |
| voltage. Halve all the figures for a 24v system. | | | | this happens but it is only when there is so much |
| Batteries need to be topped up with distilled | | | | wind that it is uncomfortable being outside - I |
| water, nothing else. So, as long as you never let | | | | know that that is subjective but is important that |
| them fall below their nominal voltage, don´t | | | | you don't think you're going to get a constant |
| worry about anything other than keeping them | | | | source of electricity unless you live in a very |
| topped up and keeping the connections well | | | | windy place. Comparing the windmill's input with |
| greased to keep out the oxygen which might | | | | other people's experiences, I would say that it is |
| corrode them. When there is no sun and no wind | | | | very useful but you would never get to float the |
| and you need to top them up, you will have to | | | | batteries from it, even if you had 48 hours of |
| use a generator. Normally, you would have a large | | | | constant 25mph wind, whereas a couple of sunny |
| enough battery bank to survive three days | | | | days will easily float the batteries. Better to rely |
| without sun but during those three days you do | | | | on the windmill as something that might avoid you |
| not use the swimming pool pump, the washing | | | | having to use the generator on a day without sun. |
| machine, your hairdryer etc. You can still use the | | | | I had the tower for the windmill made at the local |
| lighting and a few luxuries like the TV but | | | | blacksmith's of which there are plenty in Spain. It |
| common sense tells you that the more you take | | | | consists of one and a bit scaffold tubes welded |
| out of your batteries the sooner they get close | | | | together to form a 7.5 metre pole on a hinged |
| to 48 volts and then you have to act. | | | | base and supported by 5mm steel wires from |
| Generators are dirty and noisy and consume | | | | four steel plates bolted to a concrete base. At |
| expensive petrol or diesel so the less you use | | | | first, there was only one wire from each plate to |
| them the better. However, the biggest cost of a | | | | the top of the scaffold tube but the pipe would |
| generator is the machine itself. A proper | | | | definitely have buckled without a second wire to |
| generator is powered by a multi-cylinder water | | | | support it half way up and keep it rigid. |
| cooled engine and will cost you around 5,000 | | | | How to give a summary of our three year |
| new. Correctly serviced, this should last you a | | | | adventure in alternative energy in Spain? The first |
| lifetime. At the other end of the scale are little, | | | | piece of advice is to trust no one, our original |
| Chinese made, single cylinder, air cooled engines. | | | | installer has gone out of business and didn't know |
| We paid 2,000 for our first diesel one with | | | | what they were doing anyway. The more you |
| electric start and sound-proofed box and we are | | | | learn yourself, the less likely you are to make a |
| on our third which cost less than 200 and is | | | | costly mistake. Now that it is all over, I would not |
| the most basic I could find. However much you | | | | choose the option of installing a serious |
| pay for these "cheap" generators, do not expect | | | | on-demand diesel generator which seemed the |
| them to last 500 hours, even if you change the oil | | | | better way for a long time. However, I would do |
| every 100 hours and clean the air filter every 50 | | | | without the government grant and would buy all |
| hours. That is why we buy the cheapest possible. | | | | the items that I need (other than the batteries |
| NEVER lend your generator to anyone else. The | | | | which really need to be delivered to you from the |
| reason that they want to borrow yours is that | | | | factory) from eBay and fit them myself. This |
| they have broken theirs and they will return | | | | would save more money than the grant provided |
| yours in the same state. When they return it, it | | | | and, although electricity is very dangerous and I |
| might appear to work but they will have altered | | | | recommend you use a qualified electrician to |
| the speed at which the engine runs and this alters | | | | connect up your system, the whole concept is |
| the output voltage of the generator. The | | | | very easy and just takes a little common sense. |
| generator is often wired into your inverter (see | | | | |