The best guide for electronic smart lock battery life

Lithium and lithium-ion are not the same

Lithium batteries are not the same as lithium-ion batteries.  Often consumers buying AA batteries for their locks will pick up lithium batteries because they look exactly like alkaline batteries. Be careful when you buy batteries to buy only alkaline batteries for your electronic door lock unless the manufacturer specifically recommends another type of battery.

I have bought several smart locks that came with a rechargeable lock connected magnetically.  The batteries were poor performers losing the ability to open the locks after only a few weeks.  In addition, you had to pull off the lock and plug it into a charger cord.  These were expensive locks which we just replaced with a different brand because we used them in vacation rentals and needed to provide access to guests.

It’s time to talk about battery life and what causes batteries to drain prematurely.  Starting with what many lock manufacturers claim is a 12-month battery life, do not believe them.  Why?  because you will find that one size does not fit all.  

Lithium batteries vs Alkaline Batteries

Most smart lock manufacturers do not recommend the use of lithium batteries. Some forums out there claim great performance with lithium batteries and as mentioned above they should be a better-performing battery except that most smart lock manufacturers do not recommend them.

Before I knew this, I installed lithium batteries in my Kwickset smart lock. Within a month the batteries overheated and burst. While this can happen to alkaline batteries, I have not experienced it in any of the many locks that I manage. Go to the manufacturer’s website and check before you change from alkaline to any other type of battery chemistry.

Battery life will vary

Not all batteries are made the same, meaning some will last longer than others, some will provide higher power than others, etc.  Next, some locks are used once per day, others many times per day.  This is why it is not possible to give you an accurate estimate of how long your batteries will last before you experience the use of the lock yourself.

The best remaining power level to replace alkaline batteries in an electronic lock depends on several factors:

1. Lock’s voltage requirement: Different locks have varying minimum voltage requirements to function properly. Consult the lock’s manual or manufacturer’s website to find this information. It’s usually specified in volts (V).

2. Battery type and brand: Alkaline batteries have a gradual voltage decline over time. Standard alkaline batteries might start around 1.5V and drop to 1.2V or lower when depleted. High-performance alkalines might maintain higher voltages for longer.

3. Environmental temperature: Cold temperatures can affect battery performance. Batteries lose voltage faster in cold environments. So, if you live in a cold climate, you might need to replace batteries sooner than someone in a warm climate.

4. Usage patterns: If you frequently use the lock, the batteries will naturally drain faster. Heavy usage might necessitate earlier replacements compared to infrequent use.

5. Warning signs: Many electronic locks provide low-battery warnings, often through flashing lights or beeps. These are valuable indicators to replace the batteries before they completely die and leave you locked out.

Here’s a general guideline based on voltage:

• Above 80% of the lock’s minimum voltage requirement: This is the ideal zone. The batteries have plenty of juice and should function optimally.
• 60% to 80%: Performance might start to decline, especially in cold conditions or with demanding locks. Consider replacing the batteries soon.
• Below 60%: Increased risk of malfunction. The lock might struggle to operate consistently or even fail to open. Replace the batteries promptly.

Remember:

• These are just estimates. Always check your specific lock’s voltage requirements and consider the factors mentioned above.
• Don’t wait for the lock to completely die. Replace the batteries at the first sign of low-battery warnings or noticeable performance decline.
• Using high-quality, long-lasting alkaline batteries can help extend replacement intervals.

Replace lock batteries at 50% capacity or greater

It has been my experience that batteries should be replaced when they are at 50% capacity for the reasons above.  The very minimal amount of battery power required for a lock to be effective will generally degrade quickly after 50%.  

My experience consists of owning many smart locks from various manufacturers and working with many more owned by clients.  It seems counterintuitive to throw away a battery because it has 50% life remaining.  The big problem is the power to throw those deadbolts.  

It’s common in some climate areas such as near a beach for the wood in the door to warp when wet.  This can bind the bold and cause more power to be used.  

Although the battery chemistry to create an alkaline battery is similar to all manufacturers, the finished products are often different from any standard.  For example, one battery will produce 2500mAh and another will produce 2400mAh.  

Top 3 Alkaline AA Battery Manufacturers: Parameter Comparison

*Lifespan estimates based on manufacturer claims and independent testing. Actual results may vary depending on usage and environmental factors.

**Notes:**

• This table compares Duracell Ultra, Energizer Max, and Kirkland Signature, based on their readily available AA alkaline batteries. Other models and brands may offer different parameters.
• mAh rating indicates the battery’s capacity, but it’s not the sole factor determining lifespan.
• Leakage resistance claims are based on manufacturer testing. While rare, leaks can still happen under certain conditions.
• Prices are approximate and may vary depending on retailer and quantity purchased.

Best battery for smart lock battery life

Based on the table above, Duracell Optimum appears to be the best choice for an electronic deadbolt lock, considering the specific demands e.g. significant mechanical operation of locks and wifi contact:

Reasons:

• Highest Lifespan in High-Drain Devices: Deadbolt locks often activate motors and sensors, making them high-drain devices. Duracell Optimum boasts the longest lifespan (up to 90 minutes) among the three, meaning it will likely last longer on a single charge in your lock.
• Guaranteed Leakproof: Leaks, even if rare, can damage sensitive electronic components. Duracell’s guaranteed leakproof construction offers peace of mind for long-term use in your lock.
• Widely Available: Finding replacements won’t be a hassle, ensuring you can keep your lock powered without disruption.

While Energizer Max offers similar capacity and lifespan, its slightly lower performance in high-drain devices and less widespread availability make Duracell Optimum the more reliable choice for a crucial security device like a deadbolt lock.

Kirkland Signature, though tempting due to its lower price, falls short in both lifespan and high-drain performance compared to the other two. While it might be suitable for less demanding applications, it’s not the optimal choice for a deadbolt lock.

The Duracell Optimum is rated at the highest output of all alkaline batteries, the Energizer Max comes in a close second and most others are rated at lower power output. The difference may seem small but why take a chance? I recently paid $0.80 per battery for the Duracell Optimum. $3.21 for a full set. Not much considering the need to enter your house when you need to is important.

The locking mechanism encounters resistance

The lock mechanism must use more power to overcome resistance caused by poorly installed locks or warping wood.  If you discover that your lock is lumbering and having difficulty locking, perform some maintenance on the door and frame.  This is a very common reason for reduced smart lock battery life. Another problem with smart locks and battery life is direct sunlight.  

I prefer locks with a blackout screen meaning that there are no exposed buttons that can be affected by too much sun.  Direct sunlight will negatively affect locks by bleaching out their numbers and letters plus deteriorating rubber gaskets.

Some locks like the Yale Assure 2 have a glass screen and numbers light up when the screen is touched.  You will need to stand between the sun and the lock to open the door but those lighted numbers at night are easier to see.  

Temperature extremes are another issue with locks.  

The optimal operating temperature range for alkaline AA batteries is generally between 15°C and 25°C (59°F to 77°F). However, they can still function within a wider temperature range, albeit with some caveats:

Moderate Temperature Decline (5°C to 15°C and 25°C to 35°C):

In this range, you might notice a slight decrease in battery capacity and runtime. The batteries may also take longer to reach peak performance, especially when cold. However, they are still generally usable for most applications.

Significant Temperature Decline (Below 5°C and Above 35°C):

Here, the decline becomes more pronounced. You’ll experience a noticeable drop in capacity and runtime. The batteries may struggle to function at all in extreme cold or heat.

Extreme Temperatures (Below -18°C and Above 55°C):

In these extreme zones, even alkaline AA batteries can suffer permanent damage. They might leak, corrode, or even explode. It’s best to avoid exposing them to such temperatures.

Additional Considerations:

• Individual batteries within a pack might exhibit slight variations in performance.
• High-performance alkaline batteries like Energizer Max or Duracell Optimum might have slightly wider operating ranges than standard alkalines.
• Storing batteries at room temperature will maximize their lifespan and performance. Avoid extreme cold or heat, even when not in use.

Recommendations:

• For optimal performance and longevity, use alkaline AA batteries within the recommended temperature range of 15°C to 25°C.
• If you need to use alkaline AA batteries in extreme temperatures, consider using high-performance brands and monitor their performance closely.
• Store batteries at room temperature when not in use to prolong their lifespan.

You can see from the information above that allowing direct sunlight to bake your batteries will help reduce their ability to operate at optimum efficiency.  So what can be done about this if you have a smart lock exposed to high amounts of sunlight?  Buy a cover for your lock see the section below for a recommendation.

How is your smart lock connected to the internet?

Another thing you can do to extend the life of your smart lock batteries and prevent that dead battery issue is to pay attention to how the smart lock is connected to the internet.  The following indicates issues with Wi-FI signal strength can have an impact on how long your batteries will last.

Battery drain:

• Connection attempts: If your lock constantly tries to connect to Wi-Fi, even when not in use, it can use more battery. Look for settings to control this, like a “heartbeat” mode that connects only when needed.
• Signal strength: A weak Wi-Fi signal forces the lock to work harder to transmit data, draining the battery faster. Ensure a strong, stable connection near the lock.
• Lock model and features: Different models and firmware versions have varying Wi-Fi management strategies. Some locks are more battery-conscious than others.

Minimizing drain:

• Strong Wi-Fi: This reduces the power needed for the lock to connect and transmit.  It’s about Wi-Fi connectivity.  
• Limited checks: Resist the urge to check your lock status constantly. Remote actions also require data transfer, so use them mindfully.
• Battery quality: Invest in high-capacity, long-lasting batteries designed for smart home devices.

Remember:

• Even with frequent checks, modern Wi-Fi locks are designed to be efficient. Battery life depends on various factors, not just checking.
• Monitor battery levels and recharge proactively. Most locks offer low-battery alerts.

Clean your lock regularly

Electronic keyless locks should be cleaned regularly to extend battery life.  The mechanism can corrode, and the glass or face can become dirty.  Keep your lock clean to increase life expectancy.  Keep a single set of fresh batteries nearby or even in your car.  The best batteries have a 10-year shelf life as long as they are stored at room temperature.  

While my vehicle does get hot in the summer, I keep batteries in a pocket just in case.   If you have friends or children who use battery-powered items, they can use the remaining life in your old batteries.  Not many electronic devices use the kinetic energy needed to throw a door bolt.

A key consideration when shopping for a smart lock is to understand your router. Most routers will output signals at 5ghz and 2.4ghz.  The default is often only 5ghz. While many smart locks will use either speed, some will need 2.4ghz which is preferred by many smart devices. Locks, security cameras, and other devices may only perform with a 2.4 GHz signal.

Have your cable installer activate 5ghz and 2.4ghz on the router

Before your cable installer leaves, have that person set your router on both signals so your devices have a choice. One of the most popular smart locks is a Kwikset Halo which only works on 2.4ghz. When people try to install the lock and the router is only broadcasting on 5ghz, the lock will not connect. Generally, 2.4 GHz is considered better for smart lock performance than 5 GHz. Here’s why:

Advantages of 2.4 GHz for smart locks:

• Better range and penetration: 2.4 GHz signals have a longer range and can penetrate walls and other obstacles better than 5 GHz signals. This is crucial for smart locks, as they often need to be installed on doors away from the router.
• Less interference: The 2.4 GHz band is less crowded than the 5 GHz band, especially in densely populated areas. This reduces the risk of interference from other devices and ensures a more stable connection for the smart lock.
• Compatibility: 2.4 GHz is widely supported by all routers and smart home devices. This makes it easier to set up and use your smart lock, regardless of the specific router you have.
• Battery life: 2.4 GHz communication typically consumes less battery power than 5 GHz. This is particularly important for battery-powered smart locks, as it helps conserve battery life and extend the time between recharges.

In some cases where 5 GHz might be advantageous:

• Faster data transfer: 5 GHz offers significantly faster data transfer speeds than 2.4 GHz. This can be beneficial for smart locks with features like live video streaming or real-time notifications.
• Less congestion: If you have a lot of devices connected to your 2.4 GHz network, it can become congested and slow down performance. Using 5 GHz for the smart lock can help alleviate this congestion.

Ultimately, the best Wi-Fi frequency for your smart lock depends on your specific needs and environment. If you prioritize range, stability, and compatibility, 2.4 GHz is the better choice. However, if you need faster data transfer speeds or have a congested 2.4 GHz network, 5 GHz might be worth considering.

Here are some additional factors to consider:

• Distance from the router: If the smart lock is located very close to the router, 5 GHz might provide better performance.
• Number of connected devices: If many devices are connected to your network, using 2.4 GHz for the smart lock might be more efficient.
• Smart lock features: Some smart lock features, such as live video streaming, might require the faster speeds offered by 5 GHz.

It’s recommended to consult the manufacturer’s instructions for your specific smart lock model to determine the recommended Wi-Fi frequency. Additionally, you can try connecting the smart lock to both 2.4 GHz and 5 GHz networks and see which one provides better performance in your home.

Lock exposed to the sun and elements

Many smart locks are exposed to the hot sun part of the day or even rain. I recommend that you purchase a lock cover in these situations. A poly lock cover will help to prevent UV rays from damaging the face of the lock and the lock cover can help prevent moisture from impacting the mechanism of the lock.