I have been using solar power as an energy source since 1985.
I get many enquiries about the success or otherwise which prompted me to write a 42 page book titled "Solar Power for Recreational Vehicles".  This covers the following topics:

Whilst this is written specifically for New Zealand, 95% of the content also applies to the rest of the world. N.Z. latitude ranges from 33 deg to 48 deg so a little adaptation may be required for your location.

(The following are extracts from the 42 page book written by Niol Lockington and available via email.)

Self Sufficient Electrical Power for Recreational Vehicles
Introduction
A reliable self sufficient electrical power source that will operate both luxury and essential services whilst camping in an area without mains connections can significantly enhance the enjoyment obtained from one’s prized recreational vehicle. The range of destinations broadens considerably...........
........we, (well my wife actually!), consider essentials to be 1 or 2 TV’s, Video, Stereo, Hot & cold running water, arrays of instrumentation, warning systems, satellite nav systems, showers, electric flush toilets, frig/freezer,  telephone, personal HF or UHF radio comms, computer, fax , dishwasher, clothes washer, vacuum cleaner & electric toothbrush to be the mere start point!
......... the big trick is to be able to get them to operate with out being umbilical corded to the national grid. In the following pages you will see how it can be done and how one can start with a budget sized pack, and by adhering to a simple plan, design a system which can be expanded at the same ratio as the gadget acquisition. You will see alternatives set out and learn facts and figures which will take out the guess work and avoid the many pitfalls. Solar panels, batteries, monitoring systems, generators and inverters are all covered. Wiring diagrams are included which can be easily modified to suit your design ........
........115 volt, 230 volt, 12 volt, 24 volt? Alternating current, direct current? What system should .....
........Old cars, including earlier Volkswagens used a 6 volt DC system. These systems suffered badly from VOLTAGE DROP which ............. More on voltage drop later in the section on batteries. .....
...must either use a generator set (Small diesel or petrol engine driven AC generator), or an inverter....
...This can be useful to run the occasional 12 volt item, however there does exist another head ache. Should the first battery become reasonably discharged then..........
...........fine for the occasional stop over but are not the best solution if your intention is to spend weeks on end at a remote spot with no mains power.
.......if  you use the vehicles batteries to supply your living power requirements the following 3 things will happen.
·      Because the vehicle is fitted with a “starting” battery it won’t have the capacity to store your power requirements.
·      Running the battery  50% flat and recharging it dramatically reduces the life of a “starting” battery.
·      After a couple of days camping your battery may be too flat to start the vehicle.
The solution is to design the RV to have a totally independent power system for the living requirements. This means ......
........ The peace of mind from having virtually unlimited power without prejudicing the vehicles ability to start removes worry and fear and permits some serious relaxation.

Batteries
The battery stores......
..... When power is being drawn out of the battery the lead peroxide in the positive plate, and the lead in the negative plate, convert to lead sulphate. This lead sulphate builds in bulk until the electrolyte can no longer reach the remaining active material on the plates and the voltage begins to fall..........
 ......There is a tiny bit of lead lost in each charge discharge cycle that is not recovered. In “cheap” batteries the lead content in the plates is reduced right down so that the lead loss reaches critical failure 1 day after the guarantee runs out! ....
.....Approximateley 75% of battery failures are caused......

“Deep cycle” vs “Starting”
A deep cycle battery is.........

Battery capacity
The amount of power a battery ...
....approximate guide is that 1 amp/hr = ......
........and the amp/hr capacity drops. If we pulled 200 amps out of the battery above it would.........

What capacity is required?
......is a relationship between battery voltage and the state of charge ......typical fluorescent light fitting for an RV will be rated at 9 watts. If two were on they would consume power as follows:

 Question. Having worked out the current flow as 1.5 amps, how long can we run these two lights before our 200 amp/hr battery is down to it’s 50% flat level?
Answer. We can........

Solar power charging
Solar panels are photo voltaic devices in which a silicon based compound reacts.......
A system that would ideally compliment our example would consist of ........

Setting up solar panels
Much has been written on the optimum angle for mounting solar panels. It is generally accepted that the best solution is to face the panel ........... and tilt the panel ..............as per the following table.
Approximate Latitudes and best tilt Angles

 ........there are other factors to be taken into consideration. During summer months the increased altitude of the sun angle results in ..........This results in the early morning and late afternoon sun actually being at an angle greater than 90°  to .........
.....what is the solution?” Well, two answers really. To optimise the panels production of electricity the panel could........
..... other alternative would be to ......
 it is visible light rather than direct sunlight that creates the electrical energy a .............. panel actually produces more power ........

Daily Power Output of a 55 Watt Solar Panel in NZ Averaged out  over a whole Year
 

Panel  set  Flat       Set  to  best  Tilt      Using  Tracker

          (-------------Ampere / Hours   per  Day ---------------------)

Free mounting
Free mounting refers to a .....

Solar tracking systems and the RV
A tracking system can ......
...... The most significant increase coincides once again during .......

Situating the panels for best performance.
For an RV application this usually means, “Where and how do I park?”
Solar panels will produce their maximum when .....
.... the shadow of a single overhead power wire crossing the panel will reduce the output into the battery by an amount which seems totally out of proportion to the size of the shadow. This is because ........

“High noon”
The sun is at it’s highest point when it is over the meridian of a site. (Over it’s longitude) When in this ....
.... The sun angle changes at the rate of one degree every .....
If you want to be really scientific, and find the exact high sun time for your site, then first find it’s longitude off a good map. Deduct this longitude from 180° and multiply this answer by 4 (minutes of time). Deduct the time from 24:00 hrs GMT.   Example:
Longitude of Gore is 167°.
180° - 167° = 13°
13 X 4 = 52 minutes
24:00 hrs GMT. - 52 mins = 23:08 hrs GMT. is when the sun will be at it’s highest point over Gore.

Designing the circuit
So far we have ..........

........ simplest form connecting the solar panels to the battery and getting services to work is a breeze. Below is a circuit ...
 

Factors influencing electrical performance
An electrical circuit is like a chain. It is only as good .....

Voltage drop
Voltage drop, is the term used to .......
....... performance. Typical symptoms will be :
·      Battery never seeming to be charging properly
·      Lights dimmer than expected
·      TV picture shrinking or in some sets, TV cycling on and off
·      Water pump running slowly
·      Reaching your calculated 50% amp/hr discharge level far sooner than your calculation predicted
·      Accusing your wife of watching too much TV whilst you were out doing serious fishing.
Further, once voltage drop occurs, the poor performance in turn starts to produce even worse performance. This is because .......

Hygiene of System. A very common cause of voltage drop in the system is ......

Controlling the system
It is important to monitor the system’s performance to ensure it is doing the job properly. It is impossible to design a system that will cover every eventuality, for instance one week of really heavily overcast weather is obviously going to knock the stuffing out of the battery. Only by careful monitoring will you really know just where you are with the system. Listed below are some essential tools required which are easy to use....
 

Specific Gravity Temperature Correction
                                             Electrolyte Temperature

....... mentioned earlier, the Voltmeter measures the electrical pressure in the system. It therefore makes a great tool for monitoring system performance, avoiding potential damaging over volt situations, and for diagnostic purposes. It is an essential piece of kit. Get one with a digital read out so you can work with accuracy.

There is a direct relationship between the state of charge of a battery and the stabilised offload voltage.

OFF LOAD STABILISED BATTERY VOLTAGE 

The table above comes as quite a surprise to most people who often imagine that 6 Volts would be half flat and 0 volts would be fully flat.

Over voltage
An overvoltage condition exists when........

Ammeter
A good ammeter is a real ..........

Optimising the system
Essentially there are two areas in the power system that need looking after or contolling on a continual basis. Simply .......

Remote reading ammeter voltmeter

This is the “Rolls Royce” of monitoring instruments. A hefty shunt unit sits right by the battery and monitors everything that goes in or out. A couple of light signal wires then run to the display unit. They are only carrying milliamps so the display unit can be mounted anywhere at all in the RV without causing any voltage drop in the system. It is .........

.... can also read out volts. This gives the ultimate in hands on control as panels can be switched in or out, or diverted to other batteries with the results being accurately displayed right alongside. The people to order the parts from are Carrel and Carrel Ltd., and their address is XXXXXX , Morningside, Auckland. The shunt, which they will manufacture on request, is a 12 volt, 0 to 60 amp unit which costs approxiamately NZ$60.00. The display unit is a XXXXXXX red LED digital meter which costs around $112.00. To toggle the display between amps and volts requires a switch, Cat XXXX from Dick Smith Electronics for $XX and two resistors also available from DSE for a few cents. One is a 45XXX and the other is a XXXXXXXX. The meter comes factory set with one decimal place, eg will read out say, 43.8 amps and, say, 13.2 volts. The meter requires a separate power supply, absolutely independant from the RV’s battery otherwise the meter will short out. A 12 volt cellphone battery is ideal because this can be charged from the RV battery from time to time. The voltage must be dropped down to 5.0V for the display unit. The voltage regulator for this is Cat XXXXXX from DSE and costs about $4.50. This is how you put it all together. The colour code on the diagram has no signifigance, use your own. On the top left, the wires from 3 solar panels can be seen, labelled Sol 1, Sol 2 & Sol 3. Bottom left is the Shunt, shown just above the cellphone battery. Locate this securely as close to the battery as possible. Be sure to insulate it by first mounting it on a scrap of perspex and then bolting the perspex to the body of the vehicle. The terminal labelled “battery” goes to the + terminal. Put a 30 amp fuse in this line and use heavy cable, at least 10 sq mm. Use the same cable to go on the terminal labelled “load” and take this to your distribution point.  The 4 big zeros represent the digital display. The numbers above are the 10 terminals as numbered on the display unit. We only need No’s 10, 8, 2 & 1 as shown. The oval above is the voltage regulator. The going to terminal 2 on the display is bolted or riveted to the metal case of the voltage regulator. At the opposite end to the left, the small circle represents a screw fastening the regulator to the insulated plastic case in which the whole thing is built. The B & E is stamped on the regulater and stands for Base & Emitter. 
(not viewable on web)

Note that this is viewed from the front so caution when wiring it up. In order that the three switches can sit snugly along side each other, remove the terminal screws that are supplied and solder the wires directly to the terminals. The two switches on the left are “ganged” together so that they both switch at the same time. To do this takes a little skill in the workshop. Sand the switch levers down to 4mm diameter, sanding out the taper. A power-file is ideal. Take a piece of steel, 10mm X 5mm and 22mm long. Drill 2, 4mm holes in the edge far enough apart so that they will slip over the 2 ground down switch levers. When satisfied with the fit, epoxy them into place.

Below is a drawing of the panel face with a suggested label format.
(not viewable on web)

The three circles represent the switches. If this is scaled up then the circles can be cutout and this decal slipped over. The two circles on the left are the “ganged” switches which act as one. When wired up as shown, the production from the two left panels can be switched to the left, producing 24V to chage the vehicles 24V batteries, to the centre, which is off, or to the right producing 12V charging the Domestic or Living battery. The panel on the right can be directed by it’s switch, to the left, feeding 12V into the Domestic or Living battery, centre off, or to the right diverting power down to the alligator clip thus providing an external charging scource for the boat or farmbike etc. Where the power is directed is dependent on the need at the time and the state of charge of the Domestic battery. 

Separate alternator
A separate alternator fitted .........

Adding a generator
An independent generator set ........

........ Don’t be fooled by the sticker on the microwave stating “650 watts of power”. A 650 watt microwave needs around 1500 watts to start it. .......

........handling question though, which is probably the most important, can be easily tested by loading the equivilent weight of the generator, using 40kg bags of cement, on the floor above the proposed position and............ a 4g load downwards and forwards (deceleration loading) and a 2g load rearwards, (acceleration loads)  and sideways............

..... fitting a stainless steel exhaust system as with the limited running a generator generally does, the exhaust system rarely dries out, and corrodes away in a fairly short time.

A diesel is much cheaper to run than a petrol powered one, but do some sums carefully before you choose. How ..........

Inverters.
An inverter can manufacture 115 or 230 volt AC power direct from your 12 volt battery. Early inverters used a 12 volt electric motor to drive....
.... high capacity inverter running a power tool can .......
.... Here are some actual readings of a 14 inch Telefunken television which has AC/DC capability.
Running on the DC selection ..... Current draw = 3.9 amps
Running on the 230 volt AC selection, with 230 volt power being supplied via a solid state inverter ..... Current draw = 5.7 amps.

Voltage regulator
A voltage regulator can be fitted to the output of the solar panels to prevent the .....
......are some minor penalties in as much as that the regulators .......
Manual voltage regulation is ..........

Diodes in solar panel
Often a diode, ....
.... a slight voltage drop occurs across the diode which ..
.. with the thin silver band end closest to the terminal.

Construction Tips
It is highly recommended that ...
... The solder flows between the individual wire strands ....
Battery terminals should.........
 .....one connection can cause as big a headache as all the rest of the stuff put together. Ensure that ....

The Future
Right now exciting new developments are on the horizon. The new generation will see solar panels reaching ...........

Conclusion
.... aim was to introduce the reader to a dawning alternative energy so they may reap the benefits offered, and even take part in shaping it’s future. ........

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If you decide this is for you, email me and I will email you a copy in MS Word format. On receipt of the book , post a check for one of the following amounts.