Camper Van LifePO4 Batteries and High Temperatures
Introduction
This article will explore whether it is a good practice to run all of your camper van’s air conditioned air into your LifePO4 battery compartment first, and then let it trickle out from there into your van. Here’s the context:
- This involves an expensive aftermarket 12 volt air conditioner bought for a camper van like the one I installed from Undermount AC.
- I’m a Phoenix native, and I was looking into maintaining cool temperatures inside the van in the Phoenix summer when it’s 115+ degrees Fahrenheit out.
- I found some claims that his type of high heat can degrade the LifePO4 batteries to cause a drastic shortening of output and lifetime.
LifePO4 batteries are quite expensive as well, depending on the Brand you choose. For example, I have 1,600 AH (Amp Hours) of LifePO4 battery storage in my van.
- If you go with the popular gold standard Battle Born brand (I did not), this will cost you $15,051.
- My Lossigy battery bank of 1,600 AH cost $4,196.
So, I completely understand the desire to protect this investment.
However, some claim that everyone should route all the cold air from the AC directly to the batteries first and let it leak out from there. This would greatly diminish the effectiveness of the AC system. So, I researched whether this trade off was worth it.
My Experience Living in Phoenix, AZ and Selling Residential Solar
From living in Phoenix all my life, I knew that routing all the cold air to the batteries first would greatly lower the effect of the $4,000 van AC system I bought. This would especially be true in the Phoenix summer heat when I will need it the most.
The cold air would hit the hot battery compartment first, lose a lot of its coldness, and then disperse unevenly through obstructed channels to the rest of the van interior. Cold air doesn’t fill up a room anything like heat does. A gas heater in a freezing camper van will have the entire space hot in a few minutes. In contrast, cooling a van down from 120 degrees to 80 degrees can take HOURS and will consume significantly more energy.
Tesla Powerwalls Installed in Direct Sunlight
I own a solar company and have been selling residential solar here in the Valley of the Sun for six years door-to-door. Walking the streets of my beautiful city, I have seen thousands of residential solar batteries installed on the exterior of homes in direct sunlight.
It is the rule for the local solar installers to install residential batteries, like the popular Tesla Powerwall, on the exterior of houses with no attempts to shade it. This is never changed unless the customer insists, and pays extra for, and install inside the garage. Every customer I’ve sold a Tesla Powerwall (with NMC batteries) to has it installed on the exterior of their home, and I’ve never received a complaint.
These residential solar batteries are baking in DIRECT SUNLIGHT at 115+ degrees for a good two months per year. They are in 100+ degree sunlight five months out of the year. It’s rare in Phoenix for residential customers to have their solar batteries installed anywhere besides right next to the exterior electrical panel.
Since LifePO4 batteries have a higher heat tolerance than NMC batteries, I was quite skeptical about the necessity of blowing cold air on the LifePO4 batteries in my camper van.
Types of Batteries and Heat Tolerance
Let’s cover the top three types of batteries used with solar systems:
- LiFePO4 (Lithium Iron Phosphate): The most common type of battery used in modern camper vans.
- NMC (Nickel Manganese Cobalt): Commonly found in electric vehicles, portable electronics (like laptops and smartphones), and power tools.
- Lead Acid: Your van’s starter battery is a Lead Acid battery. They are the oldest type of rechargeable battery. They used to be the gold standard for all off-grid and camper van solar setups, but LifePO4 has taken over.
Lithium Iron Phosphate (LiFePO4)
Key in energy storage systems, LiFePO4 batteries are distinguished by their phosphate-based battery chemistry, which enhances safety and cycle life. These batteries are integral in high-power applications such as electric vehicles, solar energy installations, and portable power stations, gaining favor for use in camper vans and marine environments due to their reliability and long service life.
Heat Tolerances and Management: LiFePO4 batteries exhibit superior thermal stability, efficiently managing heat transfer to operate safely across a broad temperature spectrum, from about -20°C to 60°C (-4°F to 140°F). This high heat tolerance, coupled with minimal heat generation, makes them well-suited for hot climates like Phoenix, AZ. The inherent stability of their cathode materials significantly reduces the risk of thermal runaway by preventing excessive heat accumulation.
Nickel Manganese Cobalt (NMC)
NMC batteries, known for their high energy density, serve critical roles in powering electric vehicles, portable electronics, and electronic systems, contributing to their prominence in stationary energy storage applications. Despite their advantages, they require meticulous heat sinking strategies in hot environments to maintain optimal body temperatures and ensure safety.
Heat Tolerances and Management: Operating within a temperature range of about -20°C to 55°C (-4°F to 131°F), NMC batteries demand advanced cooling systems and battery management systems (BMS) to mitigate heat generation and transfer issues. Their cathode materials’ high energy density poses challenges in thermal stability, making them more prone to thermal runaway under extreme temperatures than LiFePO4 batteries. This necessitates robust thermal management to prevent overheating and potential damage to the battery’s internal structure.
Lead Acid
As the oldest type of rechargeable battery, lead acid batteries are widely used in automotive starters, uninterruptible power supplies (UPS), and backup power solutions for homes and businesses. Despite their broad application, they are gradually being overshadowed by LiFePO4 batteries in off-grid solar installations due to the latter’s superior efficiency and longevity.
Heat Tolerances and Management: Lead acid batteries typically perform best at room temperature, with their operational range extending from -20°C to 50°C (-4°F to 122°F). However, their susceptibility to heat-induced corrosion and water loss shortens their lifespan in hot climates. The lead acid battery’s vulnerability to elevated temperatures stems from its battery chemistry and design, where high temperatures accelerate the degradation of the lead plates and evaporation of the electrolyte, thereby impacting battery performance and longevity.
LifePO4 Batteries Have the Highest Heat Tolerance
LiFePO4 (Lithium Iron Phosphate) batteries are less susceptible to high environmental heat compared to lead acid and NMC (Nickel Manganese Cobalt) batteries due to several key factors related to their unique battery chemistry, thermal stability, and the way they manage heat generation and dissipation. Here’s why:
Unique Battery Chemistry
Stable Cathode Materials: LiFePO4 batteries use lithium iron phosphate as the cathode material, which is inherently more stable than the materials used in NMC and lead acid batteries. This stability means that LiFePO4 batteries are less likely to undergo exothermic reactions (reactions that release heat) when subjected to high temperatures or overcharging scenarios.
Thermal Stability
Higher Thermal Runaway Threshold: Thermal runaway is a condition where the battery’s internal temperature and pressure escalate dramatically, leading to a risk of fire or explosion. LiFePO4 batteries have a much higher thermal runaway threshold compared to NMC and lead acid batteries. This means they can withstand higher temperatures before thermal runaway occurs, making them safer in hot environments.
Lower Heat Generation: During charging and discharging, LiFePO4 batteries generate less heat than NMC and lead acid batteries. This lower heat generation contributes to their better performance in high temperatures, as there’s less internal heat to manage.
Efficient Heat Dissipation
Heat Management: Although all batteries generate heat, the structure and chemistry of LiFePO4 batteries help them dissipate this heat more efficiently. Efficient heat dissipation keeps the battery cooler, even when environmental temperatures rise, further reducing the risk of overheating.
Cycle Life and Heat Resistance
Minimal Degradation: High temperatures can accelerate the degradation of battery materials, reducing their lifespan. LiFePO4 batteries are less affected by high temperatures, maintaining their performance over many more charging cycles compared to lead acid and NMC batteries. This resistance to high-temperature-induced degradation contributes to their longevity, especially in hot climates.
Environmental Heat vs. Internal Heat
Better Tolerance to Environmental Heat: While NMC and lead acid batteries might suffer from accelerated degradation and capacity loss under high ambient temperatures, LiFePO4 batteries maintain their integrity and performance better under similar conditions. This is partly due to their ability to resist the compounding effects of internal and environmental heat.
In summary, the combination of stable battery chemistry, higher thermal runaway thresholds, lower heat generation, efficient heat dissipation, and resistance to temperature-induced degradation makes LiFePO4 batteries more resilient to high environmental heat compared to lead acid and NMC batteries. These properties make LiFePO4 batteries particularly suited for applications in hot climates, where thermal management and safety are critical concerns.
Conclusion: Using Air Conditioned Air to Cool LifePO4 Batteries is Not Necessary
Cooling LiFePO4 (Lithium Iron Phosphate) batteries in your camper van using air-conditioned air is not necessary under normal operating conditions. LiFePO4 batteries are known for their excellent thermal stability and can operate efficiently in a wide range of temperatures, typically between -20°C to 60°C (-4°F to 140°F). Here’s why cooling them with air-conditioned air is not needed:
High Thermal Stability
LiFePO4 batteries have a higher thermal tolerance compared to other types of batteries, such as lead-acid or NMC (Nickel Manganese Cobalt) batteries. They are less prone to overheating and do not require the same level of cooling to maintain optimal performance.
Efficient Heat Management
These batteries are designed to manage heat effectively on their own. Their internal structure and chemistry allow for efficient heat dissipation, reducing the risk of thermal runaway and negating the need for additional cooling in most situations.
Broad Operating Temperature Range
LiFePO4 batteries can operate in a broad temperature range without significant performance degradation. This means they can withstand the high temperatures often encountered in camper vans during summer without additional cooling measures.
No Significant Performance Boost from Cooling
While extreme temperatures (both hot and cold) can affect battery performance, the range within which LiFePO4 batteries operate comfortably means that cooling them with air-conditioned air is unlikely to provide significant benefits in most climates.
Practical Considerations
Using air-conditioned air to cool batteries could potentially waste energy that could be better used for cooling the living spaces within the camper van or for other energy needs. Since LiFePO4 batteries already handle heat well, it’s more energy-efficient to allocate cooling resources elsewhere.
Considering all of this, I will be directing my air conditioned air directly to my FACE instead of my batteries.