Advantages of Lithium Iron Phosphate in Solar Streetlights

Advantages of Lithium Iron Phosphate in Solar Streetlights

1. Charging Efficiency

Lithium iron phosphate batteries (also called LiFePO4 Batteries) can reach 100% charging efficiency.

But the lead-acid battery charging efficiency can be only 60%.

So take a 100W solar panel as an example. According to the weather conditions in Shanghai city, the daily lithium iron phosphate (LiFePO4) batteries can store about 45W-75W of electricity, while the lead-acid batteries can only store 27W-45W.

So that means 2pcs lead-acid batteries to achieve a lithium iron phosphate (LiFePO4) battery charging effect.

In other words, the battery's same capacity, lithium iron phosphate (LiFePO4) batteries can supply 60W solar street lights, while the lead-acid battery can only supply 30W of solar street lights.

2. Excellent Discharge Performance

Lithium iron phosphate batteries have a smooth discharge voltage and can discharge up to 100% at room temperature.

Lead-acid batteries have a discharge depth of up to 60-70%.

Lead-acid battery charging performance is approximately half the lithium iron phosphate discharge level and can only discharge half of the lithium iron phosphate.

In practice, the same 12V 40AH battery, lithium iron phosphate batteries can discharge 40AH of electricity

If the solar street lights work 10 hours per night, can work continuously for two rainy days;

If you take into account only half of the state's charging performance, charging one day, lead-acid batteries receive 20AH. Still, they can only discharge 10AH of electricity, can only supply continuous work half a rainy day.

The cycle life of lead-acid batteries is greatly reduced if they are frequently deeply discharged.

Suppose the lead-acid battery is often under-charged and cannot be recharged on time. In that case, the lead-acid battery generated within the sulphate particles will be large, plate active material cannot be fully utilized. In the long run, the actual capacity of the lead-acid battery will gradually diminish.

However, the lithium iron phosphate battery's charge and discharge state are reversible, and there is no memory effect. You can 100% DOD discharges in the solar street lighting system.

3. Small Size and Lightweight

Lithium-ion batteries have a volume ratio of up to 100wh/l and are smaller than lead-acid batteries. There are no space restrictions on installation.

LiFePO4 batteries of the same capacity weight are only half the weight of the lead-acid battery.

For example, the 12V 110AH lithium iron phosphate battery size specifications are 258 * 155 * 238(mm), weight: 14kg;

Lead-acid 12V 100AH battery size specifications are 410 * 175 * 212 * 240 (mm), weight: 33kg. Weight is less than half.

4. Long Service Life and Low Maintenance Costs

Lithium iron phosphate battery after 2,000 cycles, its capacity is still maintained at more than 80% of the nominal capacity, in the basic case available for 7-8 years, while lead-acid batteries need to be replaced in 3 to 5 years.

In the charge and discharge process of lithium iron phosphate batteries, the opposite volume change in the cathode lithium iron phosphate and cathode graphite, the battery's total volume remains the same, the pressure on the separator is less, the battery safety and cycle life are greater security.

Battery storage, lead-acid batteries must be recharged within three months. Otherwise, the battery will be scrapped;

But lithium iron phosphate batteries have good storage performance and storage time of up to 3 years without recharge and maintenance.

Significantly reduce labour costs, but also pollution-free.

The magnitude of self-discharge can measure the storage performance of a lithium-ion battery.

Generally, the capacity loss from self-discharge can be divided into non-recoverable capacity and recoverable capacity.

Lithium iron phosphate batteries have superior storage performance, with a monthly self-discharge rate of about 2% and a capacity recovery rate of more than 98%.

The required maintenance costs based on 1000 solar street lamps and eight years of a cumulative lifetime are.

Lead-acid batteries 4000 RMB x 1000 lamps x 8 = 32 million RMB

Lithium iron phosphate batteries 0$

5. Wide Operating Temperature Range

Lithium iron phosphate battery operating range of -20 ℃ ~ 60 ℃, that is, in the hot sun and cold conditions, the battery can work normally.

Due to the iron phosphate in the P-O chemical bond, lithium iron phosphate batteries are very strong. Even at high temperatures of 500 ℃ will not release active oxygen, and there will be no thermal runaway.

The normal operating range of lead-acid batteries is 20-30℃; when the battery temperature is too low, the capacity decreases because the electrolyte does not reflect well with the plate's active material at low temperature.

The reduced capacity will not allow the battery to meet the expected backup use time and stay within the specified discharge depth, easily causing the battery to over-discharge.

At room temperature, an ideal working controller can make the lead-acid battery fully charged, but when the ambient temperature drops to 0°C, using the same controller to charge, the result will not be fully charged.

By the same token, when the ambient temperature rises, it will be easy to cause overcharging. The electrolyte heating up will accelerate the positive plate's corrosion rate, the lead-acid battery operating temperature rises severely, will produce boiling, up and down tumbling electrolyte.

Over time, the shed lead powder will accumulate higher and higher, and when it touches the lead plate, it will cause the plate to short-circuit, and the battery will be scrapped.

When the lead-acid battery works at high temperatures, the lead-acid battery will lose water and thermal runaway, which is very dangerous.

6. Best match with solar street light charge and discharge state

The charging and discharging currents of street lights are very small; most do not exceed 10A, so for batteries, they are shallow charging and discharging, and this way of working limits the matching batteries.

For example, nickel-metal hydride batteries must be discharged and then charged; otherwise, it affects the battery's life.

For lithium iron phosphate batteries, there is no memory effect, but it will extend the battery's life.

As a leading solar street light manufacturer in China, SUNVIS has been committed to technological innovation and service improvement. Please feel free to send us any inquiries about solar street light.