Lead Acid Batteries
Table of Contents
Introduction
"Lead acid batteries are the most commonly used type of battery in photovoltaic systems. Although lead acid batteries have a low energy density, only moderate efficiency and high maintenance requirements, they also have a long lifetime and low costs compared to other battery types. One of the singular advantages of lead acid batteries is that they are the most commonly used form of battery for most rechargeable battery applications (for example, in starting car engines), and therefore have a well-established established, mature technology base. " - PVEducation
Efficiency
"Lead acid batteries typically have coulombic efficiencies of 85% and energy efficiencies in the order of 70%." - PVEducation
Benefits of Lead Acid Batteries
Drawbacks of Lead Acid Batteries
Safety Hazards
Corrosive Acid
"Batteries are potentially dangerous and users should be aware of three main hazards: The sulfuric acid in the electrolyte is corrosive. Protective clothing in addition to foot and eye protection are essential when working with batteries." - PVEducation
Electrocution
Batteries have a high current generating capability. If a metal object is accidentally placed across the terminals of a battery, high currents can flow through this object. The presence of unnecessary metal objects (e.g. jewellery) should be minimised when working with batteries and tools should have insulated handles." - PVEducation
Explosions
Explosion hazards due to evolution of hydrogen and oxygen gas. During charging, particularly overcharging, some batteries, including most batteries used in PV systems, may evolve a potentially explosive mixture of hydrogen and oxygen gas. To reduce the risk of explosion, ventilation is used to prevent the buildup of these gasses and potential ignition sources (i.e. circuits which may generate sparks or arcs) are eliminated from the battery enclosure." - PVEducation
Maintenance
"Flooded lead acid batteries are characterised by deep cycles and long lifetimes. However, flooded batteries require periodic maintenance. Not only must the level of water in the electrolyte be regularly monitored by measuring its specific gravity, but these batteries also require "boost charging". " - PVEducation
Maintencance Costs
"The production and escape of hydrogen and oxygen gas from a battery causes water loss and water must be regularly replaced in lead acid batteries. Other components of a battery system do not require maintenance as regularly, so water loss can be a significant problem. If the system is in a remote location, checking water loss can add to costs. Maintenance-free batteries limit the need for regular attention by preventing or reducing the amount of gas which escapes the battery. However, due to the corrosive nature the elecrolyte, all batteries to some extent introduce an additional maintenance component into a PV system." - PVEducation
Pollution
Lead
Lead is a dangerous heavy metal that remains in the soil around mines, manufacturing, and waste cites. Lead can absorb through skin, or contaminate drinking water. Lead causes brain damage, learning dificulties, mood swings, and other health problems.