We received a question today which we hear frequently: Would gel or AGM batteries be better in the extremely hot environment of Nigeria? This is a good question and you can hear many opinions about it in this industry. Unfortunately, sometimes the opinions change depending on what type of battery is being sold. Here are some things to consider:
Both are starved electrolyte batteries, but the gel is more severely starved, which means there is less gas to bubble or escape under over-heated conditions. The AGM, by contrast, would do better in very cold environments. Gel batteries are less likely to go into thermal runaway than AGM batteries, but you should not be putting a battery in those conditions anyway.
Neither battery should be installed in direct sun or without a cover from the rain. No battery should be installed without a temperature sensor – almost all of our inverter manufacturers now include battery temperature sensors for free in the box.
Now for practical experience – Deka has installed thousands of gel batteries to back up cable TV installations in Phoenix, Arizona. Compare the temperature in Phoenix (average high temp 40c and highest average monthly temp 33c) to the temperatures in Sokoto (average high of 35c and highest average monthly temp of 32c). In other words, Phoenix is hotter and if the batteries can do well in Phoenix, they will do well in Nigeria.
So if both types are properly cared for and properly charged, the operating temperatures in Nigeria should not make a difference. But in real-life, where they are often over-heated, abused, and over-discharged, gel would be a better choice…..
For more information, Deka publishes a VRLA manual (http://africanenergy.com/new/wp-content/uploads/2012/08/dekagelmanual.pdf ) which gives a good explanation of both technologies.