LEAD ACID BATTERIES
Using an electrolyte consisting of sulphuric acid, a battery can store impressive amounts of electrical energy in a relatively small space. This energy is stored in chemical form within lead grids mounted inside the battery. Currently, there are three common lead acid battery technologies: Flooded, Gel and AGM. All our systems use either Gel or AGM batteries and here is why.
- AGM stands for Absorbed Glass Mat, a newer type of battery construction that uses saturated absorbent glass mats. AGM batteries are sealed and therefore require no maintenance. This also means no acid spills, gassing, watering or an equalization process to contend with.
- Gel batteries use a thickening agent like fumed silica to immobilize the electrolyte. If, by chance, the battery container cracks or is breached, the battery will continue to function. As with the AGM battery, the Gel cell is sealed and user friendly as well.
- Flooded batteries are the most common lead-acid battery-type in use today. However, they do require maintenance on a regular basis. Along with the need to have the electrolyte solution topped up, specific gravity checks done with a hydrometer, an equalization process performed, they also need a specially built container or a separate ventilated room as they “off gas” (produce toxic fumes). Since the battery is not sealed, great care has to be used when working with these batteries as the electrolyte (sulphuric acid) will burn your skin!
Salt Water Batteries
A salt water (sodium ion) battery use a concentrated saline solution as its electrolyte. The batteries are non-flammable and more easily recycled than batteries that have toxic or flammable materials. Some saltwater batteries are maintenance-free, with no battery management required, and are compatible with leading power control electronics.
Unfortunately, salt water batteries have a low round trip efficiency and therefore waste energy that could be used by the consumer.
NiFe Nickel Iron Batteries
The nickel–iron battery (NiFe battery) is a very versatile battery which is tolerant to overcharge, over-discharge, and short-circuiting. The batteries can have very long life even if improperly maintained, and are often used in backup situations where it can be continuously charged and can last for more than 20 years.
Due to its low specific energy, extremely high-maintenance, poor charge retention, and high cost of manufacture, other types of rechargeable batteries have displaced the nickel–iron battery in most applications. The round trip efficiency is also very low.