The market for lead-acid batteries has steadily eroded. Although lead-acid batteries are only used in small UPS, the proportion of lithium iron phosphate batteries in large and medium UPS is increasing. Since the beginning of last year, the batteries of my country Mobile and Netcom’s telecom base stations have now all started to use lithium iron phosphate batteries. As a base station using UPS, the price advantage of lithium iron phosphate is reflected. The lithium iron phosphate battery has better high-temperature tolerance than lead-acid batteries, which can save the cost of temperature control.
Because of its voltage platform and safety performance, lithium iron phosphate batteries perfectly match lead-acid batteries. In particular, it has a cycle life of up to 4,000 times, which has prompted more and more consumers to abandon lead-acid batteries and use lithium iron phosphate batteries instead.
However, these two are not batteries of the same system after all, so when replacing, what key points need to be paid attention to?
- Battery size
Under the same specifications, the volume of the lithium iron phosphate battery is only half of the lead-acid battery, and the weight is only 35% of the lead-acid battery. In theory, the space is completely sufficient. But consider whether it can still be installed in the original position, whether it is protruding or squeezed.
- A charger matches the battery type
Because the charging mode, voltage, and current required by the two batteries are different, the original charger cannot be used directly.
- socket replacement
The interfaces of the two are generally different, and the battery must be replaced with a matching socket.
- cut-off voltage
Discharge cut-off voltage = number of blocks * battery discharge cut-off voltage. For example, a 48V lead-acid battery is 4*10.5=42V, and a lithium iron phosphate battery is 162.5=40V or 15 series of iron lithium.
- Select protection board according to motor power and controller
For example, the car has a 500-watt motor and a 60V battery. Common formula for protection board current: (500/60)*(2.2~2.5). Some motors are relatively old, the current will increase, and the current parameters should be appropriately enlarged.
- Replace the fuse
The lithium iron phosphate battery has strong power and high current, and the original fuse may burn out when it is suddenly started.
- Pay attention to capacity
Replace the lithium iron phosphate battery with the same capacity and voltage. The actual capacity of the lithium battery is more than that of the lead-acid battery. This is because the lithium battery can achieve 100% DOD, but the lead-acid is generally only recommended to be placed at 70%, otherwise Lead-acid batteries are easily damaged. Another important reason is that lead-acid batteries have poor high-current characteristics, only 50% of the capacity at 1C discharge, while lithium batteries can basically achieve 100% DOD at 1C.
Protection level: IP**, the last two numbers, the first number is the solid protection level (range is 0-6); the second number is the liquid protection level (range is 0-8). The larger the number, the stronger its protection capability. Lead-acid batteries are generally sealed or filled with instant glue, and the waterproof function is very good. But lithium iron phosphate batteries may not.
- Change the charging method
Lithium batteries have no memory effect, and the battery can be charged or discharged at any time. Of course, when it is not used for a long time, it needs to be charged regularly, after all, lithium batteries have their own power consumption.
Lithium-ion batteries (LIBs) have become the main energy storage solutions in modern social life. Among them, lithium iron phosphate battery perfectly replaces lead-acid battery, and is the first choice for grid-connected peak regulation, off-grid energy storage, photovoltaic energy storage, UPS, data center and other industries.