Windy Nation Complete Off-Grid Solar Kit - Manual (Page 17)

Complete Off-Grid Solar Kit Manual
Revision 2.0
5.6 400W (F OUR 100W P ANELS ) – 24 V OLT S YSTEM
6 BATTERIES
The battery is a critical component in your renewable energy system to store the power generated by your solar
panels and provide a relatively constant source of power when the grid is down, or during periods when your
photovoltaic system is not producing power. Although batteries are not one hundred percent efficient, they are
predictable and stable enough for reliable long-term service.
Windy Nation recommends Deep Cycle lead-acid batteries and discourages the use of car or marine batteries.
This is because car and marine batteries are designed to give a large burst of energy when starting a vehicle
and are not made for deep discharges. However, golf cart batteries are a less expensive acceptable alternative.
6.1 T YPES
There are three main types of batteries that are commonly used in renewable energy systems, each with their
own advantages and disadvantages.
1. Flooded or “wet” batteries are the most cost efficient and the most widely used batteries in photovoltaic
applications. They require regular maintenance and need to be used in a vented location.
2. Gel Cell uses a silica additive in its electrolyte solution that causes it to stiffen or gel, eliminating some of
the issues with venting and spillage.
3. Absorbed Glass Mat (AGM) construction method suspends the electrolyte in close proximity with the
plate’s active material.
Gel Cell and AGM batteries are both sealed, requiring virtually no maintenance. They are more suitable for
remote applications where regular maintenance is difficult, or enclosed locations where venting is an issue.
6.2 S IZING
All deep cycle batteries are classified and rated in amp-hours. Amp-hours is the term used to describe a
standardized rate of discharge, measuring current relative to time. It is calculated by multiplying amps and
Page 17 of 21 windy nation 03/31/2014