When it comes the moment to selecting the most efficient engine starter device for your aircraft or the most suitable portable battery-operated power station, to setting up a power backup system for your home or to choosing the right battery for any other application, you will find a lot of different options in the market, as well as very relevant differences in their prices!
So much information can even be overwhelming, but it is important to have, at least, some basic notions about the main differences between the traditional Sealed Lead Acid (SLA) and the more modern lithium batteries, with a focus in the LiFePO4 chemistry that we use in ENERCRAFT.
Let’s have a close examination of these two options, which are used in many different industrial equipment, energy storage systems, vehicles and machinery all around the world.
WEIGHT / ENERGY DENSITY
- SLA: Heavy cells (30 – 40 Wh/kg).
- LiFePO4: Up to 4 times lighter on average (110 – 250 Wh/kg).
- LiFePO4 batteries are 55% lighter than SLA batteries, which is key especially for portable devices.
CAPACITY & DEPTH OF DISCHARGE (DoD)
- SLA: 50 – 60 % DoD. VERY LOW EFFICIENCY.
- LiFePO4: Usually 80 – 90% DoD, but can handle up to 100% discharge.
- LiFePO4 density is significantly higher, therefore it can power more appliances for a longer period of time, resulting in a much higher usable capacity.
- SLA: With very high discharge rates, the capacity of the SLA batteries decreases exponentially.
- LiFePO4: Battery capacity is independent of the discharge rate.
- A major difference between LiFePo4 batteries and lead-acid batteries is that the Lithium Iron Phosphate battery capacity is independent of the discharge rate. Lithium batteries also have a longer cycle life than lead-acid batteries.
CONSTANT POWER DELIVERY
- SLA: Voltage drops quickly during discharging processes.
- LiFePO4: Voltage is almost constant during discharging processes.
- LiFePO4 batteries can constantly deliver the same amount of power throughout their entire discharge cycle. But in SLA batteries the power starts strong, but dissipates faster, and decreases gradually.
PEAK POWER DELIVERY
- SLA: Not designed to deliver high energy peaks.
- LiFePO4: Designed to deliver high energy peaks, in a safer and more efficient way.
- LiFePO4 batteries are fully capable of delivering high energy peaks, which are needed for specific applications such as performing engine starts. With the right electronics (BMS), those peaks will be delivered safely and very efficiently. SLA batteries are not designed for those applications, and will degrade very quickly if they are exposed to those requirements.
- SLA: Notoriously slow.
- LiFePO4: Charging can be 4 – 5 times faster.
- This results in less time to charge and more time for battery usage.
- SLA: Environmental factors can significantly reduce its efficiency and life.
- LiFePO4: Prepared for hard weather and environmental conditions.
- LiFePO4 batteries performance is far superior in high temperatures, compared to the SLA batteries. Lithium batteries also have a higher discharge capacity in cold temperatures.
- SLA: Usually 500 – 1000 cycles.
- LiFePO4: Up to 5,000 cycles, and improving in recent years.
- The cycle life of the LiFePO4 batteries is 10 times or more the cycle life of SLA batteries under most conditions. LiFePO4 batteries will need to be replaced much less often than SLA in every case, especially in cyclic applications.
SELF DISCHARGE (STORAGE)
- SLA: 5 times or greater self-discharge rate.
- LiFePO4: Minimal.
- The self-discharge rate of a LiFePO4 battery is 10 times lower. This means that you can store your battery, vehicle, machinery or equipment for a much longer period, performing monitoring and preventive maintenance, but without the need to recharge the batteries so often, while they are temporarily not in use.
- SLA: High chances of leakage.
- LiFePO4: LiFePo4 can be installed and used in any position as they don’t have any chance of leakage.
- This is a very important factor for logistics, storage and daily use of your batteries or energy storage devices, especially if those are portable equipment.
- SLA: Needed.
- LiFePO4: Maintenance Free. No action needed, when handled appropriately according to the manufacturer’s instructions.
- LiFePO4 batteries require no maintenance thanks to its internal chemistry, and do not need to be drained or added with water and liquid.
- SLA: Heavy Metals Environmental Implications
- LiFePO4: Do not contain pollutant Heavy Metals
- LiFePO4 batteries are more environment-friendly than SLA batteries, since there are fewer raw materials needed to create the same capacity of energy storage. More importantly, LiFePO4 batteries can also be recycled to recover the materials used in their electrodes, wiring and casings, to be then used in manufacturing new lithium batteries.
- SLA: Risk of fires and explosions
- LiFePO4: Cells cannot explode or burn through internal or external damage
- LiFePO4 batteries must always meet the requirements of the prevailing United Nations standard UN38.3, in order to receive certification for safe transport. Therefore, LiFePO4 batteries must undergo a rigorous series of tests performed by an approved independent testing laboratory to ensure they do not rupture, leak, disassemble, or catch fire, thus ensuring the excellent safety features of this type of technology.