In South Africa, load shedding has become a daily reality, leaving businesses and homes without power several times each day. Having a battery backup power system can make these challenging times far more manageable, and can help businesses stay up and running, and homes protected and comfortable.
Backup power systems are energy storage devices that can be rapidly turned on to power a home or business. However, every backup power system needs an energy source. Generators, for example, mostly run on diesel fuel, which is the main disadvantage of these solutions.
They release a lot of exhaust fumes and need ongoing maintenance much like any other diesel engine. Moreover, they need to be constantly topped up with fuel, which given the soaring fuel prices in South Africa, makes them expensive and inconvenient.
Less intrusive, more reliable
This is why many are turning to batteries instead of generators for their backup power needs. Batteries are less intrusive and far more reliable. They promise no noise or emissions and require little maintenance beyond making sure the batteries are fully charged.
In addition, while generators cost less per kilowatt-hour than batteries at the point of sale, maintenance and ongoing fuel costs make generators infinitely more costly in the long term.
Which battery to choose?
However, not all batteries are the same. Choosing between lead-acid and lithium-ion batteries can have practical considerations for any business or individual.
There are several factors that need to be considered when choosing the type of battery that is best suited to a business or individual’s needs.
- How much of the charge the battery stores can be used without causing damage to them?
- What is the cost of charging or recharging the batteries after use?
- How much space will need to be set aside to house the batteries?
- Is there any special ventilation or cooling that needs to be installed?
- What is the expected lifespan of the batteries?
- How much maintenance is required to look after the batteries?
- How long will the batteries last?
- How much of the charge held by the batteries can be used?
Lead-Acid vs Lithium Ion
While all batteries come with a rated capacity or nominal capacity which reveals how much electrical charge the battery can store, it does say how much of that storage can actually be used.
In order to avoid damage, only about 30% of the electrical energy that lead-acid batteries can store is able to be used before they are recharged. Deep-cycle batteries enable between 50 and 60% of the energy they store to be used, meaning with this type of battery, users can never regularly use above 50% of the energy that they have paid for.
If lead-acid batteries use more than this even on rare occasions their lifespan will be significantly reduced.
However, lithium-ion batteries enable users to use 90 to 95% of the energy they store every day if they choose to do so, without any damage occurring.
In essence, this means that in order to benefit from the same output a user will need to buy, install, and maintain many more lead-acid batteries than their lithium-ion counterparts.
While it’s clear that lithium-ion batteries are the clear winner over lead-acid batteries, again not all lithium-ion batteries are created equally.
While lithium-ion batteries and lithium ferrous phosphate batteries (LiFePO4) both fall under the class of lithium batteries, and have similarities, LiFePO4 batteries offer more benefits in terms of cycle life, as they last four to five times longer.
Moreover, they have the edge when it comes to safety because lithium-ion batteries can overheat and even catch fire, while LiFePO4 cannot.
Longevity and cost
Lithium-ion batteries normally offer a cycle life of between 300 to 500 cycles, which translates roughly into a time period of around two to three years. LiFePO4 batteries have a far longer cycle life of approximately 3000 cycles, which means they will last for seven years or more.
When it comes to the money spent, the cost per kWh is the amount of money a user spends for every kWh of battery capacity. And because every type of battery is available in a wide range of storage sizes, comparing them on the basis of cost per kWh is the best way to establish true cost-effectiveness.
A lithium-ion battery makes use of cobalt as an electrode material, which leads to a higher cost for the battery. LiFePO4 batteries also use cobalt-free options such as iron and phosphate, both of which are significantly cheaper.
Differences in performance
While all batteries hold some advantages over their competitors, there is no doubt that lithium-ion batteries have far more advantages over lead-acid ones. Lithium-ion is simply a more convenient and safer alternative and can be installed and forgotten about, instead of requiring ongoing maintenance.
However, it is also clear that LiFePO4 batters offer dramatic advantages in performance over normal lithium-ion ones.