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LiFePo4 Batteries

Lithium iron phosphate batteries are quite the novelty. These systems are much more powerful, long-lasting, and lightweight than traditional battery chemistries and stand out amongst other batteries due to the advantages they promise. This article will explain why this is so and run a simple test to prove a LiFePo4 battery’s superiority.

What Makes LiFePo4 Batteries Stand Out From the Rest?

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Lithium iron phosphate batteries provide a higher energy density, are lightweight, and last longer than the average battery, making them ideal in a wide range of applications:

  • RVs, boats, golf carts
  • electric vehicles
  • backup emergency power or primary power source at home
  • primary power source for living off-grid in recreational vehicles
  • off-grid power for exterior activities
  • portable solar systems

Compared to other lithium batteries, LiFePo4 batteries are nontoxic, meaning their disposal is much more practical and safe for the environment. Lithium iron phosphate batteries have more thermal stability due to their chemical composition and built-in battery management system (most LiFePo4 batteries have it).

 What Options Are There for LiFePo4 Batteries?

Lithium iron phosphate batteries are gaining traction quite quickly, and there are many options to choose from than there were just a couple of years ago. Here are three LiFePo4 batteries with the same capacity offered by three of the most popular power system brands.

  Battle Born Renogy Victron
Battery Model 100Ah 12V LiFePO4 Deep Cycle Battery 12V 100Ah Smart Lithium Iron Phosphate Battery Lithium Battery Smart 12.8V 100Ah *

Life Cycle

(# cycles to 80% DOD capacity)

3000 cycles 4000 cycles 2500 cycles
Weight 31 lb 26 17lb
Price $874 $899 $1,327

*Victron Lithium Battery Smart 12.8V 100Ah does not include BMS.

Our Recommended Renogy Lithium Battery

Advantages of LiFePo4 Batteries

Let’s review their benefits to understand why they are the top choice.

Long Life Cycle

LiFePo4 batteries have an outstanding lifespan expectancy. Compared to lead-acid batteries, which provide an average of 300 to 500 discharge cycles, LiFePo4 batteries promise up to 3,500 discharge cycles. This amount of cycles translates to 10 years of use or more.

High Energy Capacity

Lithium iron phosphate batteries provide around 50% or more electrical capacity than other battery chemistries. Thus, offering a higher power-to-weight capacity than any other type of battery in the market.

 Faster Charging

Usually, LiFePO4 batteries grant four times the energy density and charge five times faster than lead-acid batteries. They are deep cycle efficient, which means they can discharge from 100% to 0% without affecting the battery’s performance over time or damaging it.

 High Depth of Discharge

Depth of discharge (DOD) is a percentage of how much of the battery’s charge capacity has been discharged. A LiFePo4 battery has an average depth of discharge of 80% and can go up to 100%, whereas a lead acid battery has a low DOD of only 50%.

No Memory Effect

Memory effect is when a battery is charged to a specific percentage during its first charges, it will remember its previous charging percentage and recharge it to that same potential on the following charges. Lithium iron phosphate batteries can be charged to any percentage, and it won’t affect their future charging capacity.

No Maintenance

Lithium batteries do not require constant maintenance, unlike lead acid batteries, which need to be watered every few months and be used and kept under specific conditions.

Lightweight

Their main component, lithium, is the lightest metal out there. Therefore, on average, they are one-third of a lead-acid battery.

What Is the Average Price of a LiFePo4 Battery? 

Due to their top-notch efficiency and lifespan, lithium iron phosphate batteries are more expensive than any other. On average, lithium batteries can go from $600 to $1000 or more. What defines the price is not only the brand that manufactures it but also the life cycle expectancy and other features that the battery might include. These features could be Bluetooth or Wi-Fi connectivity, the warranty offered when purchased, features its battery management system (BMS) includes, etc.

Price , test and what to expect<br />

Let’s Put It to the Test

Now, let’s test how long a refrigerator will run for using a 12V 100Ah LiFePo4 battery  from Renogy. We will first do a theoretical calculation and compare it to the practical test. Simultaneously, we will do a theoretical test with the same refrigerator specifications but with a lead-acid battery, just for pure entertainment.

556kWh Refrigerator 

A typical refrigerator ranges from 300 to 800 watts. For this test, we will focus on a 556kWh refrigerator. Before preceding to the fridge’s run time per hour, we need to get the average fridge energy consumption in the following formula:

556kWh / (365 days)= 1.52 kWh per day

Then, we calculate the watts per hour the refrigerator uses:

1520Wh / (24 hours)= 63.33 Wh per hour

Next, we calculate the battery’s capacity available:

Battery capacity = DOD% × 100Ah

Lead-acid Battery Capacity

LiFePo4 Battery

Battery capacity =50% ×100Ah

Battery capacity = 50Ah

Battery capacity =80% ×100Ah

Battery capacity = 80Ah

Now, we calculate the battery’s capacity available in watt-hours with the following formula:

Wh = Battery Volts × Battery Ah

Lead-acid Battery Wh Capacity

LiFePo4 Battery Wh Capacity

Wh = 12 volts ×50Ah

Wh = 600Wh

Wh = 12 volts ×80Ah

Wh = 960Wh

Finally, to calculate the run time we will use both the battery’s Wh capacity result and the refrigerators watts per hour with the following formula:

(Battery Wh capacity) / (Refrigerator watts) = hours of run time

Run time with lead-acid battery

Run time with LiFePo4 battery

600Wh / (63.33 watts) = 9.47 hours 960Wh / (63.33 watts) = 15.16 hours

Practical Test 

Now that we have the theory, let’s get to the fun part, the actual test. We used a 2000W Pure Sine Wave Inverter . Through a battery monitor, we kept track of the battery’s parameters, which allowed us to determine the battery’s discharge progress.

In the table below, we took note of the battery’s voltage and amp hours used every few hours.

Run Time

Battery Voltage

Amp Hours

3 hours

13.4 volts

19.4 Ah

6 hours

13.1 volts

41.1 Ah

9 hours

12.9 volts

61.8 Ah

12 hours

12.3 volts

78.6 Ah

15:08 hours

12.1 volts

97.4 Ah

Keep in mind that as the battery discharges the voltage will decrease. Therefore, the run-time hours might differ depending on the battery’s brand, lifespan, and other factors.

 

12V 100Ah LiFePo4 Battery

Depth of Discharge

80%

Battery Capacity

80Ah

Battery Capacity Wh

960Wh

Refrigerator Watts per Hour

63.33Wh

Lead-acid Theoretical Run-time

9:28 hours

LiFePo4 Theoretical Run-time

15:09 hours

LiFePo4 Practical Test Run-time

15:08 hours

In this case, the theory result is the same as the practical test, a 556kWh refrigerator will run for 15 hours and 8 minutes. We can say that the theoretical and experimental results are almost exact. The lead-acid theoretical result indicates that a 556kWh refrigerator will run for much less time with a lead-acid battery than it would with a LiFePo4 battery.

Our Recommended Renogy Lithium Battery

Conclusion

After learning a LiFePo4 battery’s advantages and testing it with a 556kWh refrigerator, we can conclude that a lithium iron phosphate battery offers much more run time than a lead-acid battery. Thus, confirming that LiFePo4 batteries are the ideal choice when you need reliable power for longer periods, especially in off-grid applications.

Mireya Cervantes

Mireya Cervantes

Writer

Bachelor’s degree in Biomedical Engineering, I am also passionate about renewable energy applications and innovations. Full-time writer for Solar Home Stead, where I review and share my opinion on energy products and trends.

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