Install A BASIC Solar System

Times move on and things get better and with many people building off grid systems for lighting during power outages and for systems to run inverters for freezers and fridges, it may be wise to get a solar system. To date many solar panels have made lots of promises and failed to deliver and many for good reason, the 10W systems designed to keep car batteries topped up often failed for two reasons.

1) The 10 watt panel simply wasn’t powerful enough to provide adequate power to charge the battery as they were designed to be sat on the car dashboard, unfortunately many cay windscreens are coated to filter the sun and particularly the bits a solar panel needs.

2) Many modern cars have cigarette lighter sockets and many solar panels plug into these to maintain and charge a battery which is fine, many modern cars cigarette lighters also only work when the ignition key is in the accessory position which means leaving your car unlocked and your keys in the ignition, something your insurers don’t like. If your ignition is switched off no amount of solar power will charge your battery as it is switched off.

This meant the 10 watt panel really wasn’t large enough to charge a car battery and would only maintain it under favourable conditions and a good friend approached and asked for a solution for his horses as he has many acres and several stables and wanted light in winter to feed and water his horses. This was the basis of this installation.

Inside his stables he had lighting for the stalls and for the feed area as he filled the horses buckets here and this area was nearly always lit when he was there; we used Varta 80A/H batteries for each stable as he got these cheaply and they are excellent quality batteries, we made low profile lights using recycled materials and 12 volt LED strip and this system can be replicated by most people at home. 20W panels were chosen as they are cheap (less than £30) and come with either a PWM battery charging module separately, or a PWM module built into the panel and either will suffice and a 20W panel provides sufficient charge to trickle charge a battery, even in a UK winter so charge is always available. Some came with an MPPT charge controller but at this price level they were rare.

Always use a PWM charge regulator and never directly connect a solar panel to your battery as they can regularly have voltages exceeding 20 volts and this simply cooks your battery and dries out the electrolyte, so always use a charge controller for batteries. Always connect your charge controller to your battery FIRST and then connect your solar panel to your charge controller. When you connect your battery the light marked LOAD should illuminate and you can extinguish it, and then the solar panel is connected the PV light should illuminate.

We mounted the battery on a shelf inside the stable and this was attached to the shelf in a battery box to protect the terminals from anything falling and short circuiting them and a knock out was knocked out and a cable gland inserted, the battery cable ran through this o the charge controller. The charge controller was mounted to the wall above the battery box and within reach of the solar panel cables to ensure they reached and the correct position for the solar panel was determined and a frame was made to get it at the optimum angle for collecting the sun and it was stood off the roof to ensure air flow underneath it to cool it.
If you follow this and look at doing your own small solar installation then I would suggest studying the following; and then deciding if the extra money spent is actually worth it or not and what period the extra money spent will be recouped or not.

You can upgrade your solar panel and fit a larger unit and note that with a PWM or pulse width Modulation charge controller the maximum solar panel you will be able to fit is around 100 watts as the PWM charge controllers are only good for around 10 amps and they do not convert excess voltage into charging current they dissipate or waste it.

If you switch to the MPPT or maximum power point transfer charge controller you can easily handle 15 amps and many will handle much more and the real question is how much more does it cost and is it worth it? In my opinion for a small solar system it is not worth it, but if you look to expand your system it will certainly be a viable option as MPPT charge controllers can handle multiple solar panels or several solar panels wired in series to increase the voltage. One great advantage of the MPPT charge controller is their ability to convert excess voltage into charging current and this gives a greater efficiency of up to 30% more efficiency and if you place a PWM and MPPT charge controller alongside each other you can clearly see the MPPT charge controller is more efficient and delivers more charging current to the batteries.

If you want to stay with a basic battery charging system purely for lighting in emergency power outages then either charge controller will suffice to trickle charge a battery for off grid LED lighting and occasional power outages.
If you want to take such a system further then MPPT charge controllers are the only way to go and this means you can charge a battery bank and not just a single battery and a battery bank with an inverter would give you limited mains electricity which would be ideal for replenishing freezers and fridges, albeit for a limited number of times, but it would potentially save your food supplies for a shorter power outage.

In short you are only limited by your budget and in my opinion the solar technologies have improved sufficiently to come down in price to a reasonable level for many people to afford meaning a basic solar battery charging system is viable for so many more people. In today’s cost of living crisis it may be a viable option to go for a basic 12 volt lighting system and run this inside your most inhabited areas of your home where you need light and save on the electricity bills.

More super advice, thanks Assassin. And you may only receive an (explicit) thank you from some of us, but I have no doubt that many are grateful.

Many people like to expand their systems over time and this can potentially be a good idea if thought through and implemented correctly, get it wrong and it becomes an expensive millstone around your neck as solar panels degenerate over time and batteries fail, often without warning.

To begin with you need your total load in watts and remember 1 kilowatt = 1000 watts and you need the size of your inverter and the time you intend running it for and this figure is divided by your battery voltage. Let’s do some maths.

You have a 1 Kw inverter which is 1000 watts, you intend running it to run your freezer and calculate 3 hours running time so your calculation becomes 1000 X 3 = 3000; this is now divided by your battery voltage of 12 volts and this now gives us 3000 ÷ 12 = 250 amps. This means our battery capacity must be at least 250 amps or 250A/h and here is our first problem, you should never deplete a battery by more than 50% so this 250a/h should be doubled to 500 a/h or the runtime should be halved from 3 hours or 180 minutes to 90 minutes and if we upgrade to 500A/H battery packs we can do some basic maths.

One local battery supplier near to me lists 100A/H leisure batteries at £134.00 each and we would need 5 of them to achieve our 500 amps so this £134.00 now becomes 134 X 5 = £670.00 and this is to achieve our rating of 100 watts running for 3 hours without depleting our batteries by more than 50% and trashing them. The same supplier lists LIPO batteries of 100A/H rating at £816.00 and again 5 of these equals £4080.00 and this is critical to know when selecting batteries and once again they claim they are the best and we all know we pay dearly for the best. Now to the warranty, the lead acid batteries have a 2 year warranty while the LIPO batteries have a 6 year warranty and if we multiply the cost of the lead acid batteries by 3 this gives us £2010.00 so this assumes our lead acid batteries fail just out of their warranty and need replacing we still only pay £2010 for the same capacity and warranty of battery pack which clearly shows we need to do our maths to achieve value for money.

Now you need to calculate your required load and by this I mean only the necessities and for most people this would be their freezer as it contains their store of food and if you stay out of your freezer it will stay frozen for hours, so look at the specifications for your freezer and I actually did ours and it consumes 480 watts, the next standard size inverter is 600 watts so we can recalculate. This now becomes 600 watts X 3 hours which gives us 1800 ÷ 12 volts =150 A/H of battery capacity and if we double it to ensure we never drop below 50% discharge capacity this gives us 300 A/H and this means we only need 3 batteries of 100 A/H capacity and if we recalculate this means £402.00 for the lead acid batteries and £2448 for the LIPO batteries, if we multiple the lead acid batteries by 3 this gives us £1206.00 for the same warranty as opposed to £2448 for the LIPO batteries.

How does it work? Actually very well as I switched our fridge/freezer off for 3 hours and set it to the coldest setting and when I switched it back on it ran for 3 minutes 34 seconds which was rounded up to 4 minutes meaning it ran for 8 minutes every 6 hours or 32 minutes per day or 64 minutes for 2 days and this is crucial as it is very unlikely your power would be off for 2 days, but perfectly possible in a bad winter so this allows us another option and this is to reduce our run time to 2 hours and this changes our equation again, we now have:

600 watts X 2 hours = 1200 ÷ 12 = 100 or a single 100 AQ/H battery and again we have reduced our spending to £134.00 for the lead acid battery X 2 for ability not to drop below 50% discharge which is £268.00, and for the LIPO it would be £1632 and if we multiple the lead acid batteries costs by 3 it becomes £804.00 for the same 6 years of warranty and very few batteries last to just outside their warranty as most last a lot longer.

Can our small solar set up save us money? Actually yes as if you have a charged battery and an inverter you can power LED lighting and if you have a shed, garage or workshop you can install a couple of LED batten lights and run a small inverter and it can be the cheaper modified sine wave just for lighting instead of the more expensive pure sine wave.
As a general guide I have included the wattage of Morris LED batten lights and a 4’ unit consumes 36 watts, a 5’ consumes 45 watts and a 6’ batten consumes 50 watts of power and you can get the small 100 watt inverters for under £15 you can use your small solar installation to save you money; remember it isn’t totally free as you have to buy the batten lights and inverter to power them. 100 watts may charge your phone or laptop or it may run very small power tools and if you run them from inverter power you aren’t consuming mains electricity.

One former neighbour lost his wife and has only himself and little dog to worry about and he has been a gardener for over 60 years and had a double greenhouse on his back garden and the outbuildings of outhouse, coalhouse and sh*thouse constructed of brick and these were modified. The sh*thouse and coalhouse were knocked into one and the outhouse remained separate, the dividing wall was cut and a log burner was installed between the two in the cut out of the wall and is double sided with two doors so it can be fed from either side. His flue runs along the wall and out through the brick wall and had a 90° bend installed and a chimney fitted and this is not a particularly large or powerful heater and it consumes little wood and within 10 minutes of being lit it is hot inside both of them and windows often have to be opened to let heat out. He also has two LED batten lights in his large greenhouse and the whole lot is wired so he can run his lights from mains electricity or his batteries and he can run them all day; his battery pack is in his outhouse and has his inverter connected and it can be switched on from any of the buildings to give light to whichever one he is in and his solar panels are fitted to his greenhouse roof.

He also has a log burner in his greenhouse so it doesn’t matter which building he is in; he can have heat and light and stay in there all day, unfortunately his little dog grabs his blanket and drags it into either building with the fire lit and puts his blanket in the corner and pushes his way into it and goes to sleep.

Small solar systems can also be used to charge items such as your I pad or phone and powering a small charging station by solar can charge a solar generator and ensure several batteries are charged and maintained at full charge for immediate use.

Amazon provides us with some inverter costs and two 300w inverters cost £25.99 and £27.99 while a larger 600 watt units sufficient to power our freezer are £32.99 and £69.99 each and 200 watt or even 100 watt inverters are even cheaper.

Build A Power Station

If you have a small solar installation you can build your own power station to deliver inverter mains power and this also requires a few calculations; and if we use the same 1000w inverter rating we can calculate our battery requirements as follows.

1000w inverter ÷ battery voltage of 12 volts or 1000 ÷ 12 = 83.3 amps per hour.

If we assume we can get 4 X 100 A/H leisure batteries our calculation becomes 4 x 100 A/H = 400A/H if we wire our batteries in parallel and we divide this 400A/H by our requirement of 83.3 amps or 400 ÷ 83.3 = 4.8 and the 4.8 is the amount of hours running we get before we totally discharge our batteries. We don’t want to discharge our batteries less than 50% so we halve our runtime and this now becomes 4.8 hours divided by 2 = 2.4 hours runtime at mains voltage.

How did we build it? I constructed a trolley on wheels to make it more mobile which comprised of 3 levels and the bottom and middle layer each held 2 X leisure batteries which were clamped down and having the weight of the batteries lower down made it more stable.

On the top level I used a combined charge controller/inverter which houses a MPPT charge controller to optimise the charging efficiency of our batteries and a 1000 watt pure sine wave inverter which had two mains outlets fitted and with the batteries connected together on the bottom and middle shelf they were connected to the inverter. Power from the solar panels was connected through a dedicated waterproof plug directly into the charge controller side of the unit and charged the batteries and they were charged from two 170W solar panels on his garage roof giving him up to 340 watts of charging power and this sat there and it charged.

He had a small van and his little overhead crane lifted the unit high enough for him to push it into his van where it locked in to position and he had mains power available which he occasionally used at his allotment.

Build Your Own Generator

If you have basic engineering and fabrication skills there is no reason you cannot build your own generator to charge your battery pack and have the options of having two forms of power input and if your solar capacity is low or virtually non-existent due to snow for example; in the winter, your battery pack generator can recharge it’ basically it is a belt and braces approach. In many cases the components can be purchased if necessary and we begin with the frame and it is necessary to work out your layout which is determined by a couple of things, the rotation of your engine and the rotation of your alternator and do you want it belt driven or gear driven as a direct drive unit. With rotational directions established you can position your components on your frame and establish your layout and this is critical to getting it correct.

Next you need some technical information and this begins with your alternator maximum shaft speed as this is the maximum speed your alternator runs at and one I built used the venerable Bosch K1 unit which has a maximum shaft speed of 8000 RPM and this should not be exceeded. Next is the engine and we used a Briggs and Stratton 5hp unit as one was lying around and this was serviced and as it was from a domestic appliance it had a throttle cable and a maximum speed of 3000 RPM and the engine was run at full throttle to check this and its maximum speed was 2990 RPM which is close enough. With this speed established for both the engine and car alternator we could establish gearing and this was done through pulley sizes and we has to get 3000 RPM as close to 8000RPM as we could to get as close to maximum power as we could from the alternator and with a ratio of 2.5 : 1 we could get 7500 RPM as 3000 X 2.5 = 7500.

We found a twin row pulley of 2.5” diameter with a 1” bore for the engine complete with keyway and this slid straight onto the engine and the central bolt complete with locking tab held it all together and the engine was completed. We found a boss for the alternator shaft and I machined a 1” twin row pulley to fit the boss and this was bolted to the alternator and with an engine fitted with a 2 ½” pulley it would gear the alternator speed up to 7500 RPM and with these completed we made the mountings and bolted it all together. I wasn’t happy and made a tensioner for the pulley belts which was spring loaded and moved with the drive belts and stopped the whipping action, I also made and fitted a guard for the belts.

Next was the wiring which began with the positive terminal of the alternator and with appropriately sized cable I crimped a terminal to for the screw thread of the alternator and this was bolted on, another end was crimped on to fit the battery positive terminal and this was bolted up. With a small plate attached to the frame a slot was cut for an on/off switch and one was installed and an ignition light was collected from a local auto electrical supplier and this plate was drilled to accept this and a thinner wire had a terminal crimped to fit the battery positive terminal and ran to one side of the switch, the other side ran to the ignition light and the other side ran to the small excitation terminal of the alternator which is the smaller 6.35mm on the K1 unit, the positive connections were made. For the negative wiring we used the same size cable as the positive connections and crimped an end on to fit an alternator bolt on the housing and this was bolted to the alternator casing, this ran to the battery negative terminal. With the throttle cable shortened and its housing bolted to the plate and marked it can be easily started.

Starting procedures were simply; you switched the ignition switch on and the warning light illuminated, you switched the petrol on and switched the engine switch to the run position and pulled the starter cord and as the engine fired it drove the alternator which put the ignition light out and it was now charging.

What size was the alternator? Generally the K1 unit came from 40 amp to over 200 amp units and were, and still are available on many cars, particularly German and French cars as well as Skoda or Seat models owned by German company VAG and the unit I used was a 120 amp unit which actually came from an older BMW.

Why 12 volts? Because you can recharge your batteries in your battery pack, you can charge other batteries such as single units for stand alone lighting or even your car battery if it is flat and 12 volts is much safer then mains 240 volts, the unit is small and portable enough to be moved around and run sufficiently long enough to charge other batteries such as on allotments or in stables.

Why petrol? Solely because it was an engine we had which was reliable, long lived, and had excellent fuel economy and you only need store a small quantity of petrol and if you use the super unleaded which is E5 and add a good fuel additive you can store this for up to 6 months and it can also be used for other petrol equipment such as chainsaws if necessary so you spend relatively little. There is no reason you cannot use a small diesel engine but be aware they are heavier and the unit will not be as portable and generally they are noisier but diesel stored in sealed containers can be kept for years. You can also use older gas powered generators or the more modern dual fuel units running on either petrol or gas and any will suffice and your fuel storage will be minimal.

You can use a mains 240V generator and many come with 12 volt charging bit I have found the 12 volt side unreliable as voltages have reached over 20 volts on many units we tested and this will cook and kill a battery in no time; to charge a battery safely you will need a battery charger plugged into the generator so cut out the middle man.

Having such an alternator will ensure your batteries are charged during the lean months such as winter or during the times your solar panels may be obscured by ice or snow and you simply fire up the generator.

Love seeing your posts on self sufficiency off grid Assassin ,
I keep going the more you can see the jigsaw pieces coming together the more I stock up and prepare for what ever may be thrown at us ,
As the boxes come through the door my other half stacks them up and looks at me as though I,m not all there although he agrees it's as clear as day ,

I do know exactly what I'm doing last week I bought 3 x 25kg sacks of flour straight from the mill ,
Organic and fresh , worked out cheaper than a a small bag of basic bleached supermarket flour per kg ,
I have a bulk stock of yeast , sugar and salt so when bread is £20 a loaf my basic bread maker can run off a solar system and keep us in bread ..

The more you can do means you can become more independant and many youngsters will fail when Muck Donalds closes for good, and the more skills you can develop means the more chance you have to survive. You can make a simple Pizza oven using little more than a brick stand with a concrete top such as an old concrete slab and making a clay dome from clay dug from your garden, for luxury you can tile the concrete slabbefore making your clay top, excellent for making bread.