Energy and links to Wind, Solar power etc.

Solar and Wind Energy maps for Nicaragua

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Energy Storage

A storage battery stores electricity by a chemical change in the playtes of each cell. A flow battery stores electricity by a chemical change in the electrolyte -Example-.

This type of cell has a capacity limited only by the volume of electrolyte available.

It may soon be a practical proposition to supplant lead acid batteries as the energy storage medium of choice.

Although the cell membrane will wear out with time the electrolyte will not so the pollution problems of conventional storage batteries disappears.

Lead Acid Storage Batteries

Love 'em or hate 'em at the moment deep discharge lead acid batteries are the most practical way of storing energy 'for a rainy day'. Deep discharge batteries are not as readily damaged as a 'car' battery by repeated discharge cycles. A 'car' battery is designed to provide short high current bursts for engine starting followed by rapid recharge. They do not tolerate well the abuse of wind/solar energy.

There is much mystique about charging cycles for lead acid batteries.
-This page- gives as concise an explanation as I have found. The rest of the site is a bit precious though.
Having lived with these batteries on a boat I'd suggest the two most important points are to be obsessive about topping up with deionised water after charging and charging to vigorous gassing from time to time to stir up the electrolyte. This is called 'equalising'.

Inverters

A significant amount of the cost of a wind/solar/storage battery setup is the inverter used to turn the DC battery voltage into AC to run standard household appliances. Bear in mind that the output power rating of the inverter needs to be at least twice the maximum AC load you intend to use.

But-many AC appliances will run off DC. Anything with a brush motor in it (electric drills/saws/vacuum cleaners/fans) will run just as happily on DC as AC. 48V DC will give the same performance as 110V AC.

Many modern AC appliances use a switch mode power supply(SMPS)and will also run perfectly well on DC - indeed the first thing an SMPS does is to rectify the AC to DC. If you've got a voltmeter use it on the resistance range across the lead to the appliance with the mains switch 'on'. If it shows a very low reading (a few ohms) the appliance uses a transformer and cannot be run from DC. If the resistance reading is high (and often showing a steady increase ) you've probably got a SMPS which might well be happy with 24 or 48 volts DC. Mobile phone chargers, computers, televisions may all use SMPS.

The advantage of running selected appliances on DC is that they often have a small current draw but enough to wake up your inverter which will be running very inefficiently at a low power level.

Links to useful sites

• Solar energy in Nicaragua -- http://www.grupofenix.org/ (includes a list of their projects)
• Solar energy for Nicaragua (US based) -- http://terrasol.home.igc.org/terrasol.htm
• ECAMI -- http://www.ecamisa.com/ solar, pumps, refrigerators, communications, wind generators
• Altertec, S.A. -- http://www.altertec.com/
• Alternative Energy Store (in the US) -- http://howto.altenergystore.com/ has a good How To section