Do I need a lithium battery or a lead-acid battery?
RV enthusiasts understand that the power supply in an RV operates in a mobile, bumpy environment, often outdoors where timely charging is unavailable, and RVs are frequently left idle for extended periods. The primary role of the battery is to store energy generated from various sources and supply power to household appliances in the RV.
Lead-acid batteries are inexpensive, but they are bulky, heavy, and have a short lifespan. For RV owners who have low daily power consumption and use their RVs infrequently, lead-acid batteries can be a good choice.
However, if your average daily power consumption is around 8 kWh, you would need at least eight 100Ah lead-acid batteries. Each 100Ah lead-acid battery weighs around 30kg, meaning eight batteries would weigh about 240kg, roughly the equivalent of three adult men. Furthermore, lead-acid batteries have a short lifespan, and their capacity to store power decreases over time, requiring frequent replacements.
Lithium batteries, on the other hand, are more compact and lighter than lead-acid batteries. By using lithium-ion batteries, you can store more power in a smaller, lighter package, which means you have more space for other things in your RV! Additionally, as lead-acid batteries discharge, their voltage continuously decreases. The higher the power demand, the faster their voltage drops. Lithium-ion batteries do not have this issue; they can provide peak power at a constant voltage, regardless of the load.
Finally, lithium-ion batteries can accept a higher charging current, which means they charge much faster than lead-acid batteries.
Therefore, choosing lithium batteries is more suited to the needs of RV owners who want to carry large amounts of power in a limited space.
Is NCM or LifePO4 better for RVs?
Once you’ve chosen lithium batteries, you’ll encounter the debate between lithium iron phosphate (LiFePO4) batteries and ternary lithium batteries.
The advantage of ternary lithium batteries is their high energy density. In small passenger vehicles, they have become the first choice for power batteries. High energy density allows for longer driving range, which is crucial for electric vehicle users. Ternary lithium batteries meet this need in electric vehicle usage scenarios.
Compared to ternary lithium batteries, lithium iron phosphate batteries have a lower energy density, but they have a much longer cycle life. The extended lifespan makes them a worthwhile investment for many RV enthusiasts. A healthy lithium battery can cycle 4,000 to 10,000 times before being depleted! While the upfront cost of lithium-ion batteries is higher, the longer lifespan reduces the overall cost, potentially meaning you won’t need a replacement for more than a decade.
Lithium iron phosphate batteries are also safer. Their chemical properties are stable, and they have excellent thermal stability, only beginning to decompose at temperatures of 700-800°C. Additionally, they do not release oxygen molecules when subjected to impact, puncture, or short circuits, and they do not ignite easily, making them much safer. In contrast, ternary lithium batteries have poorer thermal stability, decomposing at temperatures of 250-300°C. In the presence of flammable electrolytes and carbon materials inside the battery, they can ignite rapidly and create a thermal runaway effect, causing an explosion in a short time.
For RVs, the battery’s main role is to store electricity generated from solar power, vehicle operation, or external power connections and supply power to household appliances. Unlike electric vehicles, where range is a major concern, RV users require frequent charging and discharging, and safety is paramount.
For these reasons, the longer cycle life and higher safety make lithium iron phosphate batteries the preferred choice for RV applications.
How to Maintain Lithium Batteries?
We recommend recharging the battery when the charge level drops to around 25%. Additionally, if the external temperature falls to around 0°C, you should charge the battery promptly to maintain its cycle life. For storage, a 50% state of charge (SOC) ensures the longest battery life. Operating below 20% SOC or above 80% SOC shortens the lifespan. Therefore, whether in use or storage, it's best to keep the charge level between 50% SOC ± 30%.
If the battery will not be used for more than 10 days, discharge it to 40% to 65%.
Every 3 months, perform a full charge and discharge cycle to maintain the battery's activity, which can extend its lifespan. Long periods of complete discharge may cause over-discharge damage to the battery cells, leading to reduced efficiency and capacity. This is particularly relevant for RV owners who might not use their vehicle for prolonged periods, thus leaving batteries susceptible to such risks.
Avoiding overcharging is as critical as preventing over-discharge. Overcharging lithium batteries can lead to excessive heat, increased internal pressure, and irreversible damage. Utilizing a smart charger that ceases charging once the battery reaches full capacity prevents the risk of overcharging.
Temperature plays a significant role in battery health. Lithium batteries operate best at temperatures between 5°C and 35°C.
Investing in quality battery management systems (BMS) can further enhance battery life and safety.
Lastly, regular visual inspections and cleaning of the battery terminals and connections are essential for maintaining good electrical connectivity and preventing corrosion. A simple routine inspection can help identify potential issues before they lead to significant problems.