Solar Power and Batteries
Powering Your Hut
Just like with Solar Panels, there are lots of great sites on the internet that will tell you all about the details and possibilities of using Batteries as part of a Solar Panel System for powering a full house & even exporting your excess energy to the Grid Some of them are a little long winded and overly technical for our purposes, so here's a summarized simple description of what you'll need to know about using Batteries to power your hut from a Solar Panel system.
Storing your batteries
Batteries are a bit like human beings...they don’t like being to cold, they don’t like being to hot. This need can be helped by building a good home for them. Treat them well they will reward you with effcient power and a long life. The Carbeth battery box is designed to help achieve these conditions. There is of course a no one size fits all solution but the principals of this design can be applied to a range of needs and battery bank sizes. The example box is designed to accommodate up to 4 Trojan T105 batteries and to fit under a standard kitchen unit. Being designed for indoors use, it has the advantage of helping to provide all the desired good battery care requirements and is accessible for maintenance.
The major disadvantage in recharging lead acid batteries is the production hydrogen gas. In certain concentrations mixed with air explosive limits could be met. Essential in preventing this outcome is a effcient maintainance free ventilation system.
The battery box provides this system by working on then very simple scientific principal. Hydrogen has only around 7% of the density of air. Being much lighter it rises, cold air is dense and drops. This can be used to set up a natural circulation system that requires no power making it maintenance free.The box is fitted with two tubes to accommodate this. A venting tube to take hydrogen out and a dip tube to provide fresh air to replace it.
Click this link to download the design PDF- Battery box Design.
Leisure batteries and car battery's - what's the difference??
A car battery is designed to give out a large amount of power in a short space of time (starting the car) and then being quickly recharged. A leisure battery on the other hand is designed to store power and release it over a much longer period of time. Undoubtedly you can use a car battery in your hut but it is unlikely to work very well in the long term. .
Preserving the life of your battery
There are a number of ways to keep your battery working longer.
• Switch off all appliances when they are not being used - consider a main shut off switch.• Avoid using high drain appliances such as televisions etc
• Keep your battery regularly topped up - check the voltage each time you're at your hut.
• Consider a battery charging device (you can use a generator or even your own car when it's running)
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Battery Banks
The following diagrams illustrate how to get increased current (more power) by using parallel wiring and how to increase voltage levels by using series wiring. You can do both using series and parallel wiring in combinations. .
Using parallel wiring to increase power and cable connections
• The cables that link your batteries together should be good and thick. It's also a good idea to make sure that the connecting cables are all the same length.
• Use crimped connectors. This will let you join different cables together into one crimped connector. Crimped connections also provide a far better connection - it's all about the amount of contact area when making connections.
This diagram shows a simple parallel circuit to increase current or power. Assume that we are using 12 volt batteries. The power of all 3 batteries add to give us the effect of a battery 3 times as powerful but the voltage stays the same at 12 volts. Parallel wiring increases current but the voltage does not change. This is the wiring used when jump starting a car for example.
Using series wiring to increase voltage
This diagram shows a simple series circuit to increase the battery voltage level. Assume that we are using really big 4 volt industrial batteries. The voltage of all 3 batteries add to give us the effect of a battery 3 times the voltage or in this case a very large 12 volt battery. In this circuit the current is the same as the current in just 1 of the batteries. But since the 4 volt industrial batteries are very large, we have in effect created a huge 12 volt battery. .
Use series & parallel wiring in combination
This diagram shows a combination series and parallel circuit to increase both the battery current and voltage level at the same time. Assume this time we are using 12 volt batteries. The left to right series connection add the two 12 volt batteries to make 24 volts. And, since we did this 3 times and then connected each group of 2 (now 24 volts) in parallel we end up with one very large 24 volt battery. It has twice the voltage of a single 12 volt battery and 3 times the current or power because all 3 groups are wired in parallel.
So, using series wiring, you can build up the voltage to the level you need and using parallel wiring you can increase the current or power. For example, you could setup a 12 volt battery bank by connecting two 6 volt batteries together in series or create a 12 volt battery bank by connecting six 2 volt batteries in series. Then just repeat this until you get the power you want and put all those 12 volt groups in parallel. Batteries for solar power systems are available in 2, 4, 6, and 12 volts, so any combination of voltage and power is possible.
The information above is equally applicable to Wind Turbines and many huts now have these set up and powering their Battery banks.
• For all the info you need on Solar Panels, go to Solar Power
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SOME GREAT LINKS FOR THIS SUBJECT
LINKING YOUR BATTERIES - The Zbattery.com website
FREE SUN POWER WEBSITE - A great source for battery set-up information
SOLARFACTS.COM - A Beginner's Guide to all things Solar Power
FAQs - A great FAQ site for everything relating to Solar Power systems
DISCLAIMER: The information contained within this page is offered as a outline guide only. Expert advice should be sought when installing electrical or venting systems.