How to estimate running time for a 12V LiFePO4 battery powering a device? Let us take an ordinary LiFePO4 battery with a 20Ah capacity as an example. With a load power of 60W (corresponding to 5A current), the theoretical life of the battery would be 20Ah/5A=4 hours. In real usage, there is an 80%-90% discharge depth constraint, and the effective power supply time is therefore brought down to 3.2-3.6 hours. Compared to traditional lead-acid batteries, LiFePO4 batteries have a life of over 3,000 times (DOD 80%), while lead-acid batteries enjoy a life of only 500 times. This means that when the daily usage charge and discharge conditions are taken into consideration, the former survives for 8.2 years, while the latter needs to be replaced after 1.4 years.
In a solar power storage unit, 1.2kWh of electric energy can be stored by a 12V 100Ah LiFePO4 battery. With a 200W solar photovoltaic panel, the daily power output is approximately 1kWh (taking 5 hours effective sunlight into consideration), which can drive continuous lighting of 3 10W LED lamps for 33 hours, or driving a 50W laptop to operate for 24 hours. According to the actual measurement values of Tesla Powerwall, a lithium iron phosphate battery system of similar capacity can increase the rate of power self-sufficiency to 65%-80% in off-grid domestic applications, significantly higher than lead-acid batteries’ 40%-50% efficient operation.
The power supply testing of the vehicle-mounted equipment states that a specified brand of 12V 50Ah lifepo4 battery is yet capable of holding 85% of the nameplate capacity at a low temperature of -20℃ and feed power to the vehicle-mounted refrigerator (power, 45W) in real-time continuously for 8.5 hours. Compared to the same family of lead-acid batteries, power supply time in low temperature declined drastically to 4.2 hours and capacity declined to 50%. Such a factor makes LiFePO4 batteries the preferred solution for polar scientific instruments research equipment. Germany’s Neumayer III Antarctic Station, for instance, is completely installed with lithium iron phosphate battery systems from 2019 and reduced its device breakdown rate by an historic 72%.
Cost-benefit calculation illustrates that though initial purchase price of LiFePO4 battery is 2-3 times more than lead-acid batteries (approximately 6,000 yuan as opposed to 2,000 yuan for the 100Ah model), calculated on a 10-year life cycle, its cost per kilowatt-hour is only 0.16 yuan per time, which is much less compared to 0.48 yuan per time for lead-acid batteries. In 2023, after Jackery’s outdoor power supply used LiFePO4 cells, the product return rate decreased from 4.7% to 0.9%. Meanwhile, it also adopts 2000W fast charging technology, which can charge 80% of the battery in 30 minutes, increasing the charging efficiency by 60% compared to the previous generation.
Environmental endurance test data show that after 2000 hours’ continuous operation of LiFePO4 battery at high temperature of 45℃, the capacity retention rate was still over 92%, while the capacity of ternary lithium batteries decreased by 18% in the same time span. This heat resistance was verified during the 2021 Texas power grid failure. The home energy storage system with lithium iron phosphate technology had only 1/5 of the failure rate compared to ternary lithium systems. The LiFePO4 battery pack, in accordance with the UL 1973 certification standard, can safely withstand 120% overcharge conditions, having a thermal runaway temperature of up to 270℃, 90℃ above that of ternary lithium batteries.