Absorbent Glass Mat Batteries

Car batteries are usually lead-acid batteries which is a well known and heavy technology. AGM, Absorbent Glass Mat, batteries offer some improvements. Will AGM batteries save our environment?

History

The first batteries made from an acid reacting with a metal plate were found in the middle east and ancient temples. Were they merely a novelty because they had no use for electricity or did people find a way to use electricity? read about the 2000 year old battery at Baghdad battery.

17??

Alessandra Cont di Volta (1745 to 1827) developed the galvanic cell, a battery using salt and metal sheets. Volta used copper and zinc plates. Zinc is still used in Zinc-manganese batteries. The term volt is derived from Volta.

1859

Gaston Planté (1834 to 1889) developed a battery using lead and sulphuric acid in 1859.

1881

In 1881 the first lead-acid battery of today's design was manufactured. Finally electric cars could replace the noisy smelly steam cars that dominated the automobile industry for 111 years. Petrol powered cars were still too noisy, too smelly and too unreliable to compete.

1885

In 1885, Gottlieb Daimler invented the first modern petrol engine and, with his partner Karl Benz, in 1886 produced the first practical petrol engine car which destroyed the electric car industry. The lead-acid battery lived on as the only easy way to start those noisy smelly petrol engine cars.

1960s

Somebody added silica to the sulphuric acid in the lead-acid battery to make the acid into a gel which made the battery spill proof. A pressure seal kept excess hydrogen in the battery so the hydrogen could be reabsorbed which reduced the need to top up the water level in the battery.

1970s

The silica in the sulphuric acid was replaced with a fine silica glass mat that absorbed the acid keeping the battery spill proof and providing a slight advantage over the gel battery. This battery is the AGM battery and features a very slow self discharge rate.

Batteries go flat even when not used. A conventional lead-acid battery will become useless in two months over winter when you need maximum power. You leave your car in the garage for several weeks then try to go for a drive and find the battery is flat. An AGM battery could last the whole winter retaining enough charge to start your engine. AGM batteries are more expensive than conventional lead-acid batteries but are worth the money for vehicles used only occasionally, especially emergency vehicles.

Spill Proof

The biggest advantage of AGM batteries is the spill proof design. Gel batteries offer almost equal spill safety which places both batteries in the same area of use. Use spill proof batteries in motorcycles because motorcycles fall over. Both gel and AGM spill proof batteries are ideal for any type of use where the batteries will not remain vertical.

The spill proof design also reduces problems with transporting the batteries. Transport costs are lower because of the safety but the weight is about the same, for a given power output, which means the energy used to transport the batteries is about the same.

The spill proof design reduces fumes which means you can use the batteries indoors as emergency backup and to store solar power for overnight use. The AGM battery overs no advantage here over gel batteries.

Short Life

All the lead-acid batteries, conventional, gel, and AGM, have a short life. They last only 200 full discharge/recharge cycles, which is less than a year for a solar powered house. The reason the batteries last three years in your car is that the manufacturers fit larger batteries that are not completely discharged each day.

Use a battery that is five times too large to get a 1000 days use or three years, which is the average lease time for a business vehicle. The main disadvantage is the extra fuel used to carry a larger battery. An environmentally friendly alternative is to use a small light battery and replace the battery every year, which means your car will fail to start at least once per year instead of once every three years.

Safety

Spill proof batteries are safer than the older design but AGM batteries show little advantage over gel batteries. You could be better off buying the cheaper gel batteries and using the lower price to get a larger battery so you place less stress on the battery.

Reliability

Spill proof batteries are more reliable than the older design but AGM batteries show little advantage over gel batteries. You get better reliability when you buy the cheaper gel batteries and using the lower price to get a larger battery.

Conclusion

Buy AGM batteries for emergency vehicles and vehicles that are used only occasionally. For everything else, the cheaper sealed lead-acid gel batteries are just as good.