24V 12V DC DC Converter
There are many advantages to using a 24V or 48V battery bank rather than the more commonly found12 Volt. Primarily, the cable used to connect the alternator/generator to the battery bank, and from the battery bank to the load appliances can be thinner since line …

Battery Desulfation
A Lead Acid Battery is made up of plates of lead in a case filled with an electrolyte (dilute sulphuric acid). When the battery discharges, some of the lead from the plates combines with the electrolyte to make lead sulfate (PbSO4) which builds up on …

AWG To Square Mm Wire Size Converter
Wire (cable) is a vital component of any renewable energy system. It is also one of the most expensive components - particularly in low voltage DC systems with long runs of wire between the generator andbattery bank. At the bottom of this article is a …

Measuring the Capacity of a Battery
The capacity of a battery tells you how much charge it can store. The rechargeable AA batteries we sell in the REUK Shop for example are rated with a capacity of 2,900mAh (=2.9Ah). This means that they can theoretically provide a current of 2.9A for …

TL431 Battery Voltage Monitor
A TL431 (pictured below) is an Adjustable Precision Zener Shunt Regulator. Its output voltage can be set to any value between 2.5V and 36V with the use of two external resistors (acting as a voltage divider). With very sharp turn-on characteristics, the TL431 is an excellent …

Make a Simple Battery Status Monitor
It is essential that the battery bank in a renewable energy system is well looked after. This means that the voltage of the battery bank must be known. It can be easily measured with a multimeter or a voltmeter, however a fun and inexpensive project …

Solar Battery Charger With LM317T
A small solar panel makes an excellent battery charger for AA and AAA rechargeable batteries. Only a few components are required and construction is very simple making this a perfect first renewable energy project. Rechargeable AA and AAA batteries have a voltage of around 1.25 Volts …

Fuses for Power Inverters
The Power Inverter is often a key component of all but the smallest off-grid renewable energy systems. The inverter takes the DC voltage from a battery or battery bank (typically 12, 24, or 48 VDC) and converts it to an AC voltage similar to that …

Interconnecting Batteries for Battery Bank
For any off grid renewable energy system the battery bank is probably the most important component. It doesn't matter how much power you generate - if it is not stored safely and efficiently then you will have no electricity when you need it. Batteries are …

Lead Acid Batteries
Lead-acid batteries store energy using a reversible chemical reaction between lead plates and dilute sulphuric acid (electrolyte). There are three basic types of lead acid battery - starter batteries: used to start engines in cars etc, deep-cycle batteries: used in renewable energy applications and camping …

12 Volt Deep Cycle Batteries for Solar
Most of our articles about lead acid batteries refer to large (20Ah+) batteries connected into a battery bank. Such battery banks are typically used for large scale solar charging - for example, to power the lighting in a home. We have also looked in detail at …

Deep Cycle Batteries For Sale
eBay is often the best place to find affordable deep cycle batteries for solar and wind generation. Prices are far cheaper typically than those of retailers however the weight of the batteries can make delivery expensive. Deep Cycle (Leisure) Batteries Below are a selection of the latest ebay …

Watt's Up Meter
Available in the USA for around $60 (and around £45 in the UK), the Watt's Up Meter and Power Analyzer (model WU100 version 2) is a combined ammeter, voltmeter, wattmeter, and battery capacity meter. The Watt's Up meter can either be powered by an auxiliary battery, …

Battery Specific Gravity
It is possible to test the state of charge of a lead acid battery (or battery bank) with a multimeter simply by measuring the voltage however this is not always an accurate indicator. More accuracy is provided by measuring the specific gravity of the electrolyte …

Power Inverters
A Power Inverter is used to convert low voltage direct current (DC) voltage (typically from a 12/24V battery bank or direct from solar panels or wind turbines) into mains power (220-240V AC in the UK, 110V AC in USA). This is very important as it …

Build a Battery Shed
In any off-grid renewable energy system the battery bank, power inverter, bridge rectifiers, charge controller, and other expensive equipment need to be housed away from the elements, close to the generation equipment, and definitely not inside the living quarters. Hence the invention of the Power …

Pure Sine Wave Power Inverters
In our article Power Inverters we introduced inverters and explained how they convert DC voltage from a battery bank into high voltage AC electricity of the type supplied by the National Grid - 230 VAC in the UK, 110 VAC in USA etc. In this article …

Minimising Line Losses in RE Systems
In most renewable energy systems low voltage DC (direct current) electricity is generated. When this is from a wind turbine generator or a hydro electricity generator there is usually quite a distance between the location of the generator and the battery bank or power inverter. If …

What Are Ultracapacitors
Ultracapacitors (sometimes called double-layer capacitors or supercapacitors) store energy electrostatically by polarising an electrolytic solution. Unlike batteries no chemical reaction takes place when energy is being stored or discharged and so ultracapacitors can go through hundreds of thousands (or even millions) of charging cycles with …

Understanding Batteries
Every day we receive emails from our site visitors about batteries. In the majority of DIY renewable electricity generating systems, the battery or battery bank is one of the most expensive and least understood components. While we attempt to offer our advice in response to …

Battery Terminals
When using a battery or battery bank in a renewable energy system it is essential to ensure that all cables are fastened very securely to the terminal posts of the battery. If you look under the bonnet of a car at the battery you will …

Keep Rechargeable Batteries in Freezer
Alkaline and lithium disposable batteries have a very slow self-discharge rate. This means that an alkaline or lithium battery left untouched for many years will retain most of its charge. This is why Duracell and other manufacturers can confidently print use by dates on their …

Equalization Charge
Individual batteries and individual cells within lead acid batteries react differently to be charged. Over time battery performance will drop as differences become more pronounced. At this stage it is necessary to perform an equalization charge (or refreshing charge) - usually once every 10 cycles, at …

Freeloader Battery Charger
The Freeloader Battery Charger is a new device for recharging AA batteries and AAA batteries directly from the USB port of a personal computer, or from a Freeloader Solar Charger. It's manufacturers claim this is the smallest and lightest AA and AAA battery charger in …

Freeplay Weza Portable Energy Source
There are now many portable solar chargers available for recharging batteries, media players, and mobile phones etc. (for example Freeloader, Solio, PowerMonkey Explorer, and even the handheld Hymini wind powered charger. While fantastic at what they do, they are obviously limited in terms of the power …

Alkaline Battery Regeneration
Every year in the UK an incredible 30,000 tonnes of single-use batteries are thrown out with the domestic rubbish. Though some are eventually recycled, the vast majority find their way into landfill sites where their nasty component chemicals and metals are buried in the ground. Many …