May 31, 2019
AGM Batteries | A Brief History
Electricity is perhaps one of the most influential scientific discoveries of the last 400 years. The citizens of developed countries rely on readily available electricity to perform a wide range of daily tasks. Without it, many modern conveniences would be impossible. It lights our homes, provides reliable refrigeration, keeps our air conditioners running, and lets us post pictures of our cats on social media through our smart phones.
It might be hard to believe that electricity has been in use for 400 years, but archeological evidence suggests that ancient civilizations may have been utilizing it 2,000 years ago or more. In 1936 a construction team working near Baghdad unearthed an artifact that has come to be known as the Parthian battery. The curious device consisted of a clay jar containing an iron rod surrounded by a copper cylinder. The jar could have been filled with a vinegar solution or fruit juice that would have acted as the electrolyte. While it is unlikely that the Parthian battery was powering ancient refrigerators or smart phones, it is believed that it was used in electroplating processes to add layers of precious metals to jewelry and other ornaments.
Fast forward to 1800. The first voltaic cell, or battery, is invented by the Italian scientist Alessandro Volta. Volta discovered that certain fluids could act as conductors and produce continuous electric power. His inventions caught the attention of France, a country very invested in scientific advancement during this era, and Volta gave several lectures at the Institute of France. He even had Napoleon Bonaparte participate in several of his experiments!
The first electric battery designed for mass production was invented in 1802 by William Cruickshank. The battery consisted of copper and zinc sheets soldered together in a sealed wooden box. Half a century later, French physicist Gaston Planté created the first rechargeable battery. This battery utilized the lead acid system we still use today. That’s right, the rechargeable battery was invented in 1859! The first camera was invented only 20 years earlier, and Coca Cola wouldn’t be invented for another 27 years.
Despite the age of the lead acid battery design it is still widely used in various applications. Lead acid batteries offer reliable energy at minimal expense. Their ability to provide cheap bulk power makes them a cost-effective option for smaller motorized vehicles, boats, and cars. They are also the batteries we at PHS West Inc. utilize in our powered carts and tugs, specifically the absorbent glass mat (AGM) variety.
So, what is an AGM battery? In the mid-1970s, the first sealed lead acid (SLA) batteries were produced. Until this point, lead acid batteries used a wet-cell (flooded) design in which a lead alloy grid was submerged in acid. SLA batteries utilize a separator that is saturated with electrolyte, creating a maintenance free battery that can function in any orientation without the risk of leaking.
The most common SLA batteries are the gel and AGM variety. The separator in AGM batteries is a woven mat of glass fiber that has been soaked in electrolyte. The advantages of this design include faster charging (up to five times faster than a flooded lead acid battery) and on demand high load currents. They are also more resistant to issues like sulfation and can be stored for longer periods of time without needing to be charged. AGM batteries are vibration resistant, making them the batteries of choice for auto-racing leagues like NASCAR.
Despite the advantages AGM batteries provide, it is still important to properly maintain them to maximize their lifespan. Fortunately, this is as simple as ensuring the battery is charged on a regular basis and operates at a safe temperature. Lead acid batteries can operate in a broad range of temperatures, from below freezing to above 100°F, however the nominal operating temperature is between 72°F and 82°F.
Charging the battery after use or after prolonged storage is the most important factor in extending its lifespan. When it comes to you PHS West Inc. equipment, this means plugging your carts or tugs in to a standard 110-Volt outlet when they are not in use. Our powered products include a built-in smart charger which prevents overcharge and should be charged at any time regardless of discharge level. In the event that the batteries are fully discharged, a full charge of between 3 and 8 hours will be necessary,
Why is My Battery Dead?
Batteries die. It can’t be avoided. Even rechargeable batteries have a finite lifespan. So why does it happen? There are a number of reasons for this, but two that can be mitigated by proper charging practice are corrosion and sulfation.
Corrosion, or “shedding”, is the result of chemical reactions that occur between the lead plates and the acidic electrolyte inside the battery. The lead plates quite literally expand and contract while discharging and charging. Over time, sulfite crystals form and cause the plates to shed material. As the plates shed, the battery loses capacity until eventually it can no longer hold a charge. It is this process that determines the anticipated lifespan, or cycle life, of a battery which is measured in charge/discharge cycles. The AGM batteries used in our equipment have a cycle life of 400-500 charge/discharge cycles (meaning 400-500 days of daily use and charging). The cycle life can be higher or lower depending on how much the batteries are discharged during each use.
Because the electrodes in a lead acid battery are always reactive, the corrosion process cannot be stopped. It can, however, be slowed by limiting the depth of discharge, using the battery in its nominal operating temperature, and avoiding overcharge.
Sulfation is another issue that can result in the premature demise of your battery. Unlike shedding, sulfation is mostly preventable. During normal use, small crystals of sulfate form. These crystals are not harmful to the battery unless it is deprived of charge for an extended period of time. If the battery is not charged, the sulphate will form crystalline deposits on the lead plates. These deposits prevent the electrolyte from saturating the active material, thereby reducing the batteries charge capacity. If the battery remains in this state for several weeks or months, the sulfation becomes permanent.
As long as the battery is charged regularly, sulfation should not be an issue. Even when not in use, batteries slowly self-discharge over time. Idle equipment and batteries kept in long term storage should be periodically charged to avoid this issue.
Got a Problem? We’ve Got You Covered!
At PHS West, Inc., we are committed to providing you the highest of quality in our products and services. Along with our 24/7 Tech Support line, we also offer battery replacement and Preventative Maintenance services to keep your carts, tugs and powered wheelchairs working hard for you and your staff. If you have noticed that your equipment isn’t working the way it used to, or you want to stay on top of replacing your batteries before they go bad, please don’t hesitate to contact us. Whatever the issue, our Technical and Customer Support staff will be more than happy to assist you.
For more information or to speak with a PHS West, Inc. customer support representative, visit our Technical Support Page.