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Welcome to the site.

A battery in good condition should easily last you the week for the purposes you describe. Running a few lights and a radio (and I imagine the water pump) at times should not drain the battery.

We have a 110 amp battery and do a lot of weekends without hook up.  Our battery will last us at least 4 days with the kids having TV and DVD plugged in as long as it is fully charged.  If we were going for a week we would take a second battery just to be on the safe side.  You could always get a second hand car battery from your local scrap yard for a few pounds.

Have you thought about changing some of your light bulbs to LED's as these reduce the power consumption a lot. 

With regard to solar panels, i think you would need quite a big expensive type to be able to charge your leisure battery to replace the amps that you would use.

Hope you have a good time at the festival.

Quote: Originally posted by Stressed Al on 18/6/2009

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Welcome to the site.

A battery in good condition should easily last you the week for the purposes you describe. Running a few lights and a radio (and I imagine the water pump) at times should not drain the battery.

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Hello and welcome.

A good portable solar panel is dead easy....simply connect your wires to the battery....face your panel south...and voila!

Quote: Originally posted by Leisurepower on 18/6/2009

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Hello and welcome.

A good portable solar panel is dead easy....simply connect your wires to the battery....face your panel south...and voila!

 

The panel is protected by both a fuse and regulator which has LED status indicators, it also has an integral stand with security chain. A sturdy protective storage bag is also supplied. The 5m lead is fitted with a continental type 12 Volt plug, a short battery connection lead is also supplied to enable direct connection to a battery. The cell type is poly-crystalline.
Typical current output at load: 3 Amp

Dimensions (mm):Length:639 Width:652 Depth:54
Weight (Kg):7

 

This is a 50 watt solar kit....40,s are also available....best thing since sliced bread.

 

Here is some useful information.

 

Solar Power, An Introduction
Solar panels or modules convert sunlight directly in to D.C. electricity. This is a semiconductor process within the silicon cells. The light energy is transferred to electrons where it is available as electricity, from this you will see that the output is dependent on the amount of light energy falling on the panel. Temperature has an effect but is negligible in comparison. Panels are usually designed to charge a battery of 12volts, during charging a higher voltage of about 14volts is required to force a charge in to the battery. A panel will have a voltage of about 20volts with no load. When the panel is connected to the battery a charging current will flow in to the battery causing the panel voltage to drop to the battery voltage of 12-14volts. Panels can also be connected in parallel, this increases the power output by adding together current produced by each panel.

The power output depends on the weather, siting of panels and many other variables - therefore exact figures are very difficult. From experience in clear sunny weather an output peak of about 80-100% of the panels rated output power can be expected. An average of 50% over the day can be improved upon by moving the panel to track the sun. As it is difficult to define light levels without expensive equipment, a guide to when panels begin to charge the battery system is that dark and grey clouds remove the direct light that the panels require to give a useful output, white clouds allow enough direct light to pass through. Overcast days will usually produce sufficient to overcome battery self discharge.

Solar Regulator
A regulator/charge controller is required when the maximum current in to the battery exceeds 10% of battery capacity in Amp hours. Use of a regulator/charge controller will prevent over-charging of the battery, and is essential with large panels or when using small capacity batteries. If the output of a solar panel is less than 10% of the battery capacity a diode may be used instead of a regulator. When the panel is able to supply power to the battery, the diode lets it through, when the panel cannot supply power (at night or in bad weather) the diode prevents the battery discharging back through the panel. Fuses should be used as a safety measure, and fitted as close to the battery as possible.

Panels can also power equipment directly, these should be loads such as fans and pumps, not voltage sensitive equipment like televisions, radios etc. When using solar power to charge a battery, equipment can be connected and used at the same time, the battery will stabilise the voltage.

Types of Solar Cells
Essentially four solar cell technologies are available commercially:

Single Crystal Silicon (Mono-Crystalline)
Cells are sliced from a pure crystalline silicon ingot.
The most efficient available commercially (~15% conversion efficiency).

CIS (Copper Indium Diselenide)
Representing the latest development in Thin film technology solar cells. Approximately 11% efficient.

Poly-Crystalline or Multi-Crystalline Silicon
Molten silicon is poured into a mould and then sliced into cells. Now the most efficient technology (~16% conversion efficiency).

Amorphous Silicon
Commonly used in toys, calculators and consumer electronics. Thin film technology, inexpensive but least efficient alternative (~8% efficient).


What size of panel do I need?Required for 12 Volt Battery Charging (ideal conditions).

This depends on the size of battery you have, the amount of power you use and the amount of light available each day. In power terms we measure the amount of energy consumed in amp hours. A 1 Amp draw over 2 hours is a total of 2 Amp hours (AHr) of current.

Determine the number of Amp hours you will use to run your electrical equipment in one day such as lights, TV, Stereo. If you divide the wattage of the equpment by 12 this will give you an approximate Amp per hour rate.

e.g A typical 15" LCD Television rated at 36 watts uses approximately 3 Amps per hour.

The maximum current available from a solar panel is given by dividing the panel Wattage by 17.

e.g. A 75 Watt solar panel will give a maximum charging current of: 75 divided by 17 = 4.4 Amps per hour.

Where possible it is a good idea to reduce the amount of energy you consume our low power TV's and Low energy Lights are good solutions.

Fitted or free standing?
For maximum performance solar panels should be orientated facing south. If any part of the panel is shaded it will not work. A solar panel produces most power when it is tilted towards the sun. Our portable free standing solar kits allow the angle to be altered to the most efficient for maximum output. A panel mounted flat on the roof of a vehicle will perform efficiently in the summer months. However in winter will lose efficiency as the sun is lower in the sky. We recommend at least an 80 watt panel for roof mounting.

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