The question of which batteries one should use for various purposes is a challenging one. Most alarm and other security systems have been using lead-acid batteries for many years, and the number of installed systems continues to grow.
While there are different options in terms of what type of batteries one can use and which are better for different purposes, something which is top of mind for everyone as Eskom’s failure continues unabated, is that, in most instances the cost of the solution plays a key role in decision-making. Additionally, in today’s environmentally conscious world, the ability to recycle used batteries is also important.
While the market is pushing lithium-based batteries as the battery of choice these days, Vaughn Tempelhoff from Forbatt spoke to Hi-Tech Security Solutions about the viability of lead-acid batteries and how to get the best performance from them. One must always remember that while lead-acid batteries are cheaper to buy than lithium-based batteries, the total cost of ownership over a longer period is what determines the real value of the purchase.
With this in mind, we started by asking Tempelhoff about lifespan; how to get the longest lifespan and optimal performance from your valve regulated lead-acid (VRLA) battery (also called a sealed lead-acid battery).
Tempelhoff notes that the lifespan of a battery will vary considerably depending on how it is used, how it is maintained and charged, the temperature it operates in and other factors. Different types of batteries naturally have different lifespans due to differences in design.
For VRLA batteries operating at around 250°C, Tempelhoff says one can expect 3-5 years in standby service, while the Gel design (as opposed to AGM) can offer 5-8 years in standby service. For VRLA long-life batteries, customers can expect 8-12 years in float charge (float charge is the voltage the battery is maintained at after being fully charged to compensate for ‘self-discharge’). Similarly, he says a VRLA deep-cycle battery can offer 8-10 years in common use or ‘nominal number of cycles’ (a deep-cycle battery is designed to be ‘deeply discharged’, using most of its capacity).
Getting the best lifespan
VRLA batteries are designed to eventually wear out, also known as a sacrificial design (of course, the very nature of batteries means that all batteries of any design will eventually wear out and come to the end of their life). This is due to the reaction of the lead electrodes and electrolyte during discharging and charging. However, by taking care of the batteries their lifespan can be prolonged, and similarly, when the batteries are not maintained their lifespans will decline.
Tempelhoff recommends that when a battery’s capacity is reduced to 60% of its nominal capacity (the original capacity), that means its grid has corroded and expanded, the active material within the casing has deteriorated and the electrolyte is drying out (or has dried out). Batteries in this condition should be replaced. The 60% charge is simply an indicator and there can be other reasons a battery has reached its end of life, such as poor maintenance.
To ensure maximum VRLA battery life, Tempelhoff suggests that setting the maximum depth of discharge to 30% and fully charging it after each use will give a battery better long-term performance and a longer lifespan. Naturally, he also recommends that users pay attention to maintenance and the temperature of the environment where they are stored.
Don’t throw it away
While we are used to throwing away dead batteries, such as torch batteries and even mobile phone batteries, that is not a good idea. All batteries should be recycled to ensure their impact on the environment is minimised – especially when it comes to the larger batteries used in UPSs and in solar installations.
A benefit of the lead-acid battery is that it has been around for a long time, so the recycling technology and techniques have matured considerably. This means that the recycling process is reliable, but also more economical in scale. Since we know that our batteries have a limited lifespan (even if it is measured in years), it is worth checking with your supplier to see how they deal with end-of-life batteries and can assist customers when the time to recycle them arrives.
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