What to read to start on Solar?

[Swallow]

So I've mean mean to start building a solar/wind setup for ages now. Starting small & adding as required.

Maybe including a 12V circuit in the house or something along those lines.

I've also noticed that Maplins have adaptors for running Laptops from 12V and that there is a in-car entertainment scene in the US that sells devices for running a non-laptop computer off 12V.

I know about invertors but 12V appeals somehow.

A dodgy set of glow plugs that was misdiagnosed leaves me with a servicable heavy duty battery. We also have a 3 way fridge running off the mains that started out as a camping fridge but has become an extension to an under counter fridge.

So I could walk into Maplins & pick up a panel for little money but.... not well versed in outputs, modulators (if that is right word) etc.

What books/other does anyone recommend to read about how all the components work with each other as a system?

 

[vestlenning]

El from the sun is fun, but expensive for what you get. As for long term, the panels will last, but batteries wear out pretty quick and the regulators as well...

 

[Robson Valley]

The village of McBride is at the end of an unreliable 500 mile power line. It is rare for a week to go by without at least one outage lasting from a few seconds to several hours.
I have the usual forced-air, oil-fired central heating set-up in my house. For about 1/2 the cost, I run a Harman PP38+ wood pellet stove. 4-5 tons of wood pellets per winter.

You will agree that at -20C, it is in my best interest to stay warm. The Harman has 3 electric motors which draw a sum of approx 500W. So, I set up a small solar power system
which can operate the wood stove for 8 hours.
75W solar panel. Charge controller. 2 x 6VDC deep cycle batteries. 1.2kW pure sine wave inverter for 117VAC. "Smart" battery charger to charge the batteries at night when the grid
comes back on and the solar panel does nothing. It is effective and reliable = it has to be.

 

[vestlenning]

Robson Valley, in your case a small scale solar solution is a good idea. If ones grid power is reliable, not so much.

 

[Robson Valley]

Absolutely correct, vestlenning! Just one of those things that I felt compelled to set up. All my neighbors know that they can camp in my house if need be.
Hindsight tells me to buy 2 more 6VDC deep cycle batteries, they run about $250.00 each. When the grid fails, that's where the juice comes from.
Modern LED lights use so little power that I can light up the house instead of flickering candles.

Wood heat, over the fuel cost of the oil furnace, saves me about $1,100 - $1,200 per year.
1. The entire capital cost of the Harman wood stove, pipes, etc, was recovered in the first 3 winters of operation.
2. The capital cost of all the solar equipment was recovered over the next 2 winters.

The initial capital outlay seemed a real grunt at the time but I cannot be happier with the outcome over the years (12?).

 

[mrcharly]

I wouldn't use a 12V setup. 12V batteries, sure, but then use an inverter. You lose a lot in transmission if running 12V everywhere and 12V devices are often expensive.

Have a conventional AC mains setup and drive it from an inverter connected to a battery bank. You need a power charge controller between your batteries and your panels or wind power. It's essential and the place to spend some cash, don't stint on it.

One deep cycle battery will keep up with supplying a laptop and a few lights. Forget running a fridge from it.

I used to live off grid on a boat, so have a fair bit of practise at this sort of setup. 3-way fridges are really inefficient compared to domestic fridges, wouldn't even try to run one from solar myself, just use gas.

Where do you live, swallow? Do you have much roof space for panels?

 

[Robson Valley]

Fine points for me to finish:
1. When I was shopping for batteries, I was told that the charge storage capacity depends upon battery plate surface area.
That's why I bought 2 x 6VDC and connected them in series for 12VDC. Together, they have more plate surface area than a 12.
2. The newest 12VDC deep cycle battery with the plate area equivalent to the two 6VDC batteries was far to heavy for me to carry! That settled that.
3. I'm running 8ga. wire from the solar panel, maybe 25', to the charge controller and batteries. Would have bought 6ga if I could have.
Heed mrcharly's advice = long runs of 12VDC are not the way to go.

 

[Ogri the trog]

I seem to recall reading somewhere that in order to start the "self-generation" route, you should first make the best of what you already have - insulation, draught-proofing etc. The idea being that if you sink all your capital into generating power that you use for heating that then blows out of a leaky window or draughty door - you could waste a lot of money!
I did a lot of research using CAT (Centre for Alternative Technology) as a lead-in and subscribed to their "Clean Slate" magazine for a while.

We currently have a sub 4Kw favorable FIT system that pays us more than we spend for electricity - and while there is no battery back-up, we could spend a wad of cash for not much gain in the greater scheme of things

ATB

Ogri the trog

 

[Swallow]

I wouldn't use a 12V setup. 12V batteries, sure, but then use an inverter. You lose a lot in transmission if running 12V everywhere and 12V devices are often expensive.

Have a conventional AC mains setup and drive it from an inverter connected to a battery bank. You need a power charge controller between your batteries and your panels or wind power. It's essential and the place to spend some cash, don't stint on it.

One deep cycle battery will keep up with supplying a laptop and a few lights. Forget running a fridge from it.

I used to live off grid on a boat, so have a fair bit of practise at this sort of setup. 3-way fridges are really inefficient compared to domestic fridges, wouldn't even try to run one from solar myself, just use gas.

Where do you live, swallow? Do you have much roof space for panels?

Currently renting a maisonette, so zero roof space, house is approximately west facing, so garden in the east. Meaning most sun gone by 1.30.

Less than ideal huh?

Having seen people put small panels in car windscreens, presumably to trickle charge the car battery for a long park or something.
I wondered if the front of the house can be utilised in the same way. Interest in that kind of thing first sparked by the solar setup in this thread

http://www.bushcraftuk.com/forum/showthread.php?t=98286

Also it's as much about learning about these things as saving buckets of money.

Ogri mentions very sensibly about insulation etc. but as renting options are reduced.

 

[Bishop]

What books/other does anyone recommend to read about how all the components work with each other as a system?

Anything & everything you can get your hands on for free. All physics textbooks should have some basic electrical/electronic theory in them and of course there is a wealth of info online.
Electronic circuits for most applications such as battery chargers & power converters are also widely shared amongst enthusiasts on the Internet in collections known as 'Circuit Cookbooks', worth a look if going down the learning/ DIY route. At the most basic level technical skill is not required, sure it helps but it's not essential. Once you understand what the symbols look like as actual components and have got the hang of soldering you can dive straight in building some quite complex kits.
Manufacturers of Integrated Circuits also produce data sheets for every device from humble voltage regulator to more complex Buck-Boost voltage converters and these will often include a basic 'How-To' circuit diagram along with all the technical stuff plus limits not to exceed or things will go pop & start smoking, what wire goes where kinda thing.

Maplin really has gone down hill over the last decade so do google around for components, they used to sell kits of bits to build your own 12-to-240 volt power Inverter but alas no more. I should point out that even modern ready made ones are woefully inefficient on average you only get 35% of the energy from the battery being stepped up to mains voltage. Things gets even worse charging a laptop as it only needs 15-19volts depending upon the actual model so the step-down conversion from mains voltages also dumps energy in the form of heat. Things are a lot better though when you use a purpose made 'Boost Converter' between the battery and a laptop as less work is done moving & stacking electrons (awful analogy I know) to change 12v into 15-19v so the setup becomes typically over 70% efficient. Better still if the device/laptop battery pack can be powered/charged directly from the solar panel(s) with just a voltage/current limiting regulator.

Sunlight of course is a rare commodity in the UK so alternatively another electronic component worth a much closer look is the Peltier Module (sometimes called a Peltier Cooler* or Thermo-Electric-Heatsink). These are what perform the magic inside the Biolite and Power-Pot stoves and come in wide range of sizes/power outputs not just USB/5v so capable of directly charging way more than just a cell-phone. All you need to provide is something that will burn and something to burn it in.... concepts that I'm sure all bushcrafter's are familiar with and what little electronics required is just a simple voltage regulator to protect whatever it is being charged. A chimney/exhaust of sorts leading outside is also desirable for safety when operating indoors.

*When you apply power to Peltier module they work in reverse and you'll find them inside those horrible little desktop fridges that hold a single beer can.

 

[mrcharly]

While bishop has some sound advice, I think a lot of it should only be followed both those who really know what they are doing. Connecting a laptop to a DC source, even via a voltage/current limiting regulator, is very risky.

Decent modern inverters are a lot more efficient than 35%. Energy losses for low voltage DC transmission can be higher than losses in the conversion from DC to AC anyway (unless you run humongous and expensive cables).

I agree with the suggestion to look at peltier devices. There is a lot of fun and learning to be had there, for little cash.

The 12V doctor is a very old book that is still an excellent starter read for those know to 12V DC power http://kb-kbh.dk/shipslib/el_ombord/12volthandbook.pdf

 

[Robson Valley]

In many respects, the city of Prince George is still considered "remote" for the holiday travellers in their gigantic motor homes (aka land yachts). As big as a Rock Group tour bus.
I went to the PG business which supplies, installs and repairs the electrical systems in those vehicles. By then, I knew that I needed 500W x 120VAC continuous for 8 hours.
Not an elective choice just simple necessity in my situation.

The guy drew a block diagram on a piece of paper. Then he said: "We sell everything you need, including the wire and terminals to connect it all."
$1,500 dollars later, I drove home with the complete kit (my Post #3). Black-to-black, red-to-red, plus-to-plus, neg-to-neg. Push the single button.

Imagine a cold (-20C) sunny winter day, maybe 36" snow on the ground, no wind. BANG! Power is off for might be a couple of hours.
The very first time that I went downstairs, started the inverter, and plugged in the stove was a psychological satisfaction.

Ask yourself 2 questions: Do I want to do this or do I need to do this? Sum up all the applications for total power needed & duration.

mrcharly: thanks for the link to the 12VDoctor book = great start. And, the marine applications are available, world wide.

 

[bridget]

http://www.primrose.co.uk/-p-82.html
Examples of Solar use.


Solar Water Fountains Outdoors start from £20 approx. Suggest you look at Argos or Local garden centre deals and see if a tracking solar-pannel, will work in your own bit of land.

As there light and can be moved easily, from one spot to another & turnned around to face the sun's direction.

if it tracks you can workout how big your solar array needs to be for your 12volt battery to fully charge in the shortest time. Test it out yourself It will depend on the size & type of pannel you have or can buy.


Tony

 

[Swallow]

Here's a belated thanks to everyone who posted. Been way too busy to get back on and do so earlier.

 

[Robson Valley]

Start by figuring out how much juice you need and for how long. That dictates your batteries (AHr) and the inverter.
Which inverter? Square wave, modified square wave, full sine wave?????? They double+ in cost as you go up.

Next, look at the number of solar panels that can keep you juiced up. Obviously, they are of no help at night, whether they can "track" or not.
At -20C, I need juice. I need 500W minimum for 8 hrs minimum to keep my wood pellet heating stove alive and well.
Avalanches upscrew everything where I live. Rock slides and mud slides come next, in June.

This winter just passed, maybe 8hrs total grid failure, possibly 3 hrs max for the longest outage.