Advantages of LifePO4 (Lithium iron phosphate batteries)

Lithium iron phosphate batteries (LiFePO4) offer lots of benefits compared to lead acid batteries, namely: Longer life span, no maintenance, lightweight, improved discharge and charge efficiency.

Lithium has a long lifespan

Lithium iron phosphate batteries live up to 2000 cycles at 80 percent depth of discharge, without decreasing in performance. The average lifetime of lead acid is 150 – 200 cycles.

High Efficiency

Lithium iron phosphate batteries (LiFePO4) have 100% of their capacity available. Additionally, their fast charge and discharge rates cause them to be a great fit for all sorts of applications. Fast charging  educes any downtime and increases efficiency.

Lightweight

Lithium iron phosphate batteries (LiFePO4) offer high power density which causes lithium batteries to be relatively small and light. Compared to lead-acid batteries lithium provides great energy density and are at least half the mass.

No Active Maintenance

Lithium iron phosphate batteries (LiFePO4) don’t require active maintenance to extend their service life. Also, the batteries show no memory effects and due to low self-discharge (<3% per month), you can store for months. Lead-acid batteries need to be cycled every 2 months as the acid will start to sulphate on the top of the battery and will start decreasing the life of the battery.

Lead Acid has historically been used in Inverter / UPS Applications. Based on the historical infrequent load shedding (2008 – 2020) of stages of 1 and 2, one would achieve a 2-3 year lifespan on the battery. 

A Lead Acid Battery is cheaper than a Lithium battery however it does come with its limitations in the current Load Shedding environment that we are experiencing.

A lead acid battery is designed for backup application with capacity of 150 cycles. Eskom’s load shedding schedules of propose daily load shedding are in a range of up to 4 hours for a few days a week. The reality is that it could be shorter, longer and with frequencies from twice a day up to every 3 days or more. This daily load shedding condition represents a cyclic (recurring) application for batteries that are meant for application as a standby / backup. Therefore, early capacity loss of ones battery can be expected, leading to earlier battery replacement as one goes through the number of cycles of a battery sooner than expected.

Lead acid batteries are designed for occasional (infrequent) load shedding, at stage 1-3. The average life span of these batteries is 2 to 3 years which has been experienced by the battery manufacturers over the past 15+ years. The current load shedding schedules have resulted in reduced run time on the batteries. The advent of stage 4-6 has significantly reduced this indicative lifespan of the battery.

In addition, a lead acid battery in normal conditions needs to be overcharged in a range of 5 to 10 percent, an inverter application requires around 72 hours to reach this stage after a deep discharge; therefore, under current Eskom Load Shedding conditions with daily discharge if the battery bank is exposed to deep discharges the battery bank will not be fully recharged when the next load shedding occurs the next day and so on. This leads to a fast capacity loss due to insufficient recharge and plate crystallization which might damage the battery permanently