Wednesday, March 13, 2013

Off-Grid Power {Battery Bank}...

8:23 pm - 49 degrees - partly cloudy...

We have been living off-grid for almost three years now.  During that time, our only source of power has been our Honda EU 2000i generator.  We have been piecing together our off-grid power system one piece at a time, and our latest purchase was the battery bank. 

Our battery bank --- eight standard 6 volt deep cycle lead-acid batteries.
This will get us up and running but we really need a total of 16.

Solar and wind energy can be as fickle as the weather they depend upon.  Therefore, anyone hoping to escape from the grid by turning to these renewable forms of energy must have a good storage systems set up to supply all of their power needs when the sun has set and the winds have become still.

Battery banks are the best choice for renewable energy storage.  By using batteries to deliver energy captured from the sun and the wind in a consistent and reliable form, you will not be left dependent on the whims of nature as you attempt to leave the electrical grid behind them.

Putting in a system of batteries to harvest and store the output of the sun and the wind involves more than meets the eye.  Before installing a battery bank, much thought, care, and calculation will be necessary to ensure that the system chosen will fully meet the energy needs of the household in a cost-efficient way.

Deep cycle batteries are the best choice for home energy systems.  'Deep cycle' simly means that the batteries in question can handle being regularly dishcarged and recharged on a regular basis.  They have the ability to store large amounts of energy for when it is needed.  The sun, wind, hydro or generator keep the battery bank charged, which supplies DC current to the inverter, which then converts that energy into the AC current that is required to power household appliances.

Lead-acid batteries come in two styles, sealed or flooded, and while the latter is cheaper it also requires greater levels of maintenance.  Batteries for renewable energy storage usually cost between $80 and $200 each , and the lifespan of a lead-acid battery is usually somewhere between one and 15 years, depending on the quality of the battery chosen and on how well it is taken care of.

The battery technology is advancing so rapidly right now, that it wouldn’t be wise to invest a large amount of money in the battery system at this point, for us at least.  Within the next five years there will be large advances in off-grid home batteries; this is why we choose to get eight standard 6 volt deep cycle lead-acid batteries.  Once the eight batteries are wired together in a series, it will give us one 48 volt battery. 
 

OUR OFF-GRID POWER CHECK LIST:
(A basic off-grid system is made up of nine components.)
 
     Power Source --- Solar, Wind, Hydro, and Generator – whatever system will be creating your electricity.

  X  DC Disconnect --- this is a breaker between the power source and the inverter.  This allows you to disconnect from the power source to troubleshoot errors.  (Housed in the Power Center – click here)

  X  Charge Controller --- this keeps the batteries from overcharging and from being discharged by the power source.  (Housed in the Power Center)

  X  Battery Bank --- stores excess electricity.

  X  System Meter --- this is like a small computer.  It describes how the various components in your system are behaving and allows you to program virtually every aspect of the system.  (Housed in the Power Center)

  X  Main DC Disconnect --- this is the breaker between the battery bank and the inverter.  (Housed in the Power Center)

  X  Pure Sine Wave Inverter ---this is the component that transforms the DC (direct current) electricity, which is yielded by the power source and stored in the battery bank, into the AC (alternating current) electricity that can be used on your appliances in the home.  (Housed in the Power Center)

  X  AC Breaker Panel --- this is the same breaker panel that is found in any home that is tied to the grid.

  X  Backup Generator --- an important source of backup power when the power system is insufficient for the demand.

     Hidden Expense --- all the wiring that is needed to connect everything together; conduit and fittings; small insulated shed aka ‘power house’ with two rooms, one room for the battery bank and one room for all the other electrical components.