How To Protect Your Battery Against Cold Weather

As the winter months approach, many of our customers will be relying on lithium-ion batteries to power devices even in frigid temperatures. Whether you need your electric vehicle to start on those below-freezing mornings or want to keep your power tools running on job sites, it’s important to understand how cold weather can impact battery performance and what you can do to safeguard your investment.

Using Batteries in Cold Weather

How Cold Weather Affects Batteries

Winter weather takes a toll on battery performance through its effects on electrochemical processes. As temperatures drop below freezing, the chemical reactions inside the battery slow considerably. Research shows reaction rates may decrease by 30% or more just below 0°C/32°F.

This slowing occurs because battery electrolytes, the medium that allows ion flow during charging and discharging, become more viscous at colder temperatures. The lower electrolyte conductivity restricts how fast ions can move between the anode and cathode. Studies have found electrolyte viscosity increases exponentially with falling temperatures.

The drop in reaction speed and ion flow hampers a battery’s ability to provide power. Capacity tests on lithium-ion cells found over a 50% reduction when taken from 20°C to -20°C. Repeated charge/discharge cycles in the cold can also stress battery components over the long run. Some evidence suggests this stress may accelerate aging effects like capacity fade.

Prolonged exposure to freezing conditions has even been known to cause damage at electrode-electrolyte interfaces in rare cases. To maintain peak performance through winter, batteries require strategies to minimize these detrimental cold-induced impacts on their underlying chemistry. With proper precautions, batteries can still offer usable power in freezing temperatures.

How Different Battery Types Perform in Cold Weather

Cold temperatures affect various battery chemistries differently. Lead-acid batteries like AGM and flooded varieties struggle below freezing, with capacities dropping over 50%. Frozen electrolytes can crack flooded cells. Lithium-ion batteries maintain usable power to lower temperatures than lead-acid. With the right handling, lithium may offer an edge in winter applications due to its superior tolerance to cold. Upcoming sections will explore lithium and lead-acid cold-weather characteristics further.

AGM Batteries

Absorbed Glass Mat (AGM) batteries represent an improvement over traditional flooded lead-acid in tolerating freezing conditions. Where flooded lead risks electrolyte freezing and plate cracking below 0°C/32°F, AGM batteries can typically deliver some capacity even at these temperatures.

However, research shows AGM performance still degrades significantly as temperatures dip below freezing. Tests conducted by Battery University found AGM capacity dropped by over 35% when taken from 20°C to 0°C. Another study published in the Journal of Power Sources tested multiple AGM models down to -18°C, finding capacities reduced by 45-55% on average at this temperature.

The glass mat material in AGM batteries helps immobilize the electrolyte, preventing freezing and expansion damage to plates. But the mat also increases electrolyte viscosity at low temperatures compared to flooded lead-acid. This thicker electrolyte impedes ion flow between positive and negative plates during discharge.

While more tolerant of freezing than flooded lead, AGM batteries still face limitations in truly cold winter conditions below 0°C. Their internal chemical reactions slow considerably due to electrolyte thickening. This makes delivering high currents difficult and reduces usable energy storage at low temperatures. For reliable winter performance, alternative chemistries may need to be considered.

Flooded Batteries

Of all major rechargeable battery types, flooded lead acid is most vulnerable to freezing conditions. When temperatures dip below 0°C/32°F, the liquid electrolyte inside standard flooded cells is prone to icing. Once frozen, expansion of the electrolyte can generate pressures over 1000 pounds per square inch, often cracking lead plates and ruining the battery.

Lab tests have found that flooded lead-acid capacity decreases by 60% or more when cooled just to -18°C. One automotive industry study recorded average capacities falling by a catastrophic 75% below freezing. With electrolyte freezing points around -60°C, these batteries cannot deliver power in cold weather.

Even if freezing is avoided, flooded lead performance still drops off steeply due to electrolyte thickening at just slightly warmer temperatures. A study published in the Journal of Power Sources measured a 40% reduction in available energy from flooded cells taken from 20°C to 0°C.

Flooded lead chemistry offers poor tolerance for freezing conditions common in winter climates. Unless used in extremely mild areas, these batteries require removal, storage in a heated space, and reinstallation for the cold months. Alternative sealed designs like AGM overcome freezing but face capacity losses below 0°C.

Lithium Batteries

While lithium-ion batteries still face performance declines in freezing temperatures, research shows many chemistries maintain usable power well below 0°C. Tests conducted by EV manufacturers like Tesla have demonstrated lithium batteries can discharge close to specified capacities even at -30°C.

A study published in Nature Energy investigated the low-temperature capabilities of lithium nickel manganese cobalt oxide (NMC) cells. When cooled from 20°C to -20°C, these batteries exhibited a capacity loss of only 15%. Comparatively, lead-acid and lithium iron phosphate chemistries dropped 50-60% at the same temperature.

The electrolytes used in lithium-ion batteries tend to be less affected by viscosity increases at cold temperatures compared to liquid electrolytes in lead-acid designs. Studies have found many lithium electrolytes see only small conductivity changes down to -20°C. This allows lithium chemistry to continue internal reactions and deliver currents effectively in freezing conditions.

Some advanced lithium formulations are engineered specifically for winter applications. Cells using lithium nickel cobalt aluminum oxide (NCA) and lithium titanate anode chemistries have received UL certification for continuous discharging down to -30°C. These high-performance batteries maintain 80% of room temperature capacity at -20°C.

With proper battery and thermal management, lithium technology remains a top choice for powering electric vehicles, tools, backup generators and more in freezing climates. While no battery escapes cold-weather impacts entirely, lithium offers the most robust low-temperature performance of major rechargeable options on the market today.

Temperature vs. Capacity

Tips to Protect Your Batteries from Cold Weather

Following best practices can safeguard the performance of batteries braving freezing conditions. Proper selection, storage, and maintenance are key. Choosing chemistries rated for anticipated temperatures optimizes output. Effective management throughout the season helps batteries last. Upcoming sections cover techniques like battery monitoring, temperature control, and inspection to keep power flowing this winter.

Choose The Right Battery For Your Working Conditions

When selecting a battery technology to withstand freezing temperatures, the most critical factor is understanding the lowest ambient temperatures it will experience in use. Without this knowledge, there is a risk of choosing a chemistry that cannot deliver the necessary power and energy when temperatures drop.

Studies show lithium-ion and AGM lead-acid batteries generally maintain the highest capacities at temperatures near and below freezing, with performance declining less sharply than flooded lead-acid. For example, tests of lithium cobalt oxide cells found capacities reduced by only 10% at -20°C compared to 50% for lead acid at the same temperature.

However, not all lithium or AGM batteries are created equal. Manufacturers typically provide minimum and maximum temperature operating ranges based on chemistry. Cells rated for -30°C or lower may be required if regular sub-zero Celsius use is expected. It is also important to account for potential acute temperature swings that could cause brief freezing, not just average lows.

Applications requiring high discharge currents or energy throughput in winter conditions may need batteries with above-average capacity to compensate for cold-induced losses. The energy density advantage of lithium becomes even more valuable at low temperatures.

For critical functions, advanced battery packs with integrated thermal management can potentially expand the usable temperature window by several degrees Celsius compared to unregulated cells. Heating enables reliable lithium or AGM performance in very cold environments.

Make Sure The BMS is Suitable For Your Battery

A battery management system (BMS) plays an important role in maximizing output from lithium-ion batteries in freezing conditions. Advanced BMS designs incorporate temperature sensors and control firmware tailored to each chemistry’s unique cold-weather characteristics.

Studies show BMS features like temperature compensation and thermal regulation can help lithium cells maintain 80-90% of their room-temperature capacity even at -20°C. Without a properly calibrated BMS, that same battery may only reach 50-60% capacity in the cold. The BMS safeguards the battery from damage caused by freezing while still enabling power delivery.

  • Look for a BMS that safeguards the battery from damage caused by freezing while still enabling power delivery.
  • Look for a BMS certified for the battery’s intended temperature range. Leading manufacturers rate their BMS down and safeguard the battery from damage caused by freezing while still enabling power delivery.
  • Look for a BMS certified for the battery’s intended temperature range. Leading manufacturers rate their BMS down to -40°C when paired with suitable lithium chemistries. Effective low-temperature BMSMS safeguards the battery from damage caused by freezing while still enabling power delivery.
  • Look for a BMS certified for the battery’s intended temperature range. Leading manufacturers rate their BMS down to -40°C when paired with suitable lithium chemistries. Effective low-temperature BMS algorithms adjust charge/discharge curves to electrolyte thickening effects. They also prevent freezing through active heating if equipped with a temperature control circuit.

Regular firmware updates can optimize the BMS for a battery’s changing performance profile as it ages. This protects the investment and lifespan even in variable winter conditions. An advanced BMS represents a relatively small added cost for major returns in energy throughput, safety, and calendar life.

Place The Battery In A Dry Place with A Suitable Temperature

When not in use during cold winter months, it is critical to store batteries in an environment conducive to maintaining their optimum performance parameters. High or low humidity, along with exposure to freezing temperatures, can significantly accelerate battery aging.

Studies show lithium-ion chemistry is particularly sensitive to moisture ingress, which can cause corrosion of internal components. When humidity rises above 60% relative, the risk of corrosion increases exponentially. Storing lithium batteries in a cool, dry place with temperatures between 0-25°C and relative humidity below 50% helps minimize these degradation pathways.

For short-term storage of a few weeks, most battery types can be kept near room temperature, provided freezing does not occur. However, longer-term lithium storage extending for months is best conducted at temperatures between 15-20°C. Data indicates capacity and impedance changes are least pronounced within this narrow window.

Ventilated indoor areas like an unheated garage or shed offer protection from the elements while still allowing airflow. Uninsulated outdoor sheds are inadvisable, as temperature swings may cause condensation. Thermal runaway is also a risk if the battery is exposed to fire or high heat, so avoid direct sunlight and other ignition sources.

Proper storage conditions preserve the battery’s charge level and internal health during seasonal downtime. This ensures it can reliably deliver design performance when power is again required in colder weather applications.

Inspect Battery Condition Periodically

Batteries sitting unused or in partial use during winter months still require periodic inspection and maintenance. Even when not cycling, internal processes continue that can affect long-term health. Checking battery voltage every 4-6 weeks can identify cells in need of reconditioning before damage occurs from deep discharge.

Lab studies show lithium-ion batteries left for extended periods at voltages below 3V/cell risk accelerated aging effects. Keeping lithium chemistries at 3.8V or higher through occasional refresh charging helps maintain maximum storage capacity. Voltage readings below 3V should trigger a recharge cycle for prevention.

Visual checks are also important, as battery swelling or leakage can serve as early warning signs of failure. These issues are better addressed promptly before safety becomes compromised. Thermal damage from overheating can similarly degrade internal components over time and should be monitored.

Simple maintenance like these routine inspections adds little effort to the valuable information gained about the storage battery’s state of health. Identifying issues early allows for corrective action that can gain months to years of additional service life – a worthwhile investment for equipment requiring winter power.

Inspect Battery Capacity

While voltage checks provide useful status updates, the true measure of a battery’s health is its capacity retention over time. Cold temperatures can permanently degrade storage over winter use or storage. Conducting capacity tests before and after seasonal downtime helps quantify any loss in amp-hours.

Discharge the fully charged battery under a known, steady load. AGM and flooded lead-acid types can be load tested with a battery load tester or portable jump starter. For lithium, a battery analyzer capable of constant-current discharge is needed. This process delivers the battery down to its low-voltage cutoff, showing the total amp-hours delivered.

Comparing results to the battery’s rated capacity at 77°F reveals real-world percentage retention. Industry experts consider more than 20% loss from the original capacity rating as the point where replacement is recommended. This threshold balances performance against safety and cost.

Catching such degradation early allows upgrading to a larger capacity replacement before a critical failure occurs. The investment of an hour’s testing saves far greater downtime and expense in the long run. The periodic evaluation also establishes a performance baseline as the battery continues through future winter/summer cycles.

With proactive maintenance like capacity tracking, batteries can reliably power equipment for their full economic lifetime, even when braving extreme seasonal temperature swings.

Conclusion

With some basic precautions, lithium-ion batteries can reliably power devices even in freezing conditions. Choosing a chemistry suited to anticipated temperatures, a well-designed BMS, and proper storage practices will help maximize performance and service life through winter months.

Our customers can feel confident relying on lithium power, knowing we stand behind the quality and cold-weather durability of every battery that leaves our factory. Stay charged up this season!

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