Replacement Batteries for eufy Smart Locks

As Amazon Associates, we earn from qualifying purchases. This means we may receive a small commission at no extra cost to you if you click through and make a purchase.

Choosing the correct eufy door lock battery means understanding whether your hardware relies on an original factory power pack or a third party eufy battery designed to keep your entryway secure. When smart entry hardware loses power, motorized latches and digital keypads stop functioning, making an extra power cell essential for zero-downtime rotation. Smart hardware owners frequently discover that distinct lock generations take specific form factors. A lock utilizing a eufy s330 battery cannot house a pack made for the FamiLock generation, nor will a lock battery operate inside a video doorbell housing. Deciding between official factory replacements and aftermarket packs involves evaluating stated capacities, charging ports, and exact chassis model numbers so that continuous security remains straightforward.

Across Amazon listings, power solutions for this ecosystem divide into three clear operational categories: original manufacturer packs built by Anker and eufy, aftermarket high-capacity cells tailored for video-enabled locks like the S330 and S230, and dedicated modules designed for newer platforms like the FamiLock series or dual-camera doorbells. Listing data shows that while some packs advertise standard 10,000 mAh capacities with universal 5V inputs, third-party alternatives offer extended capacities up to 15000 mAh or integrated USB-C ports directly on the cell housing. Navigating this lineup requires matching your hardware model code—such as T8520, T85Z0, or T85Z1—directly to the compatible replacement battery to ensure a seamless swap at the doorway. If you are evaluating door hardware, exploring a eufy door lock setup will show you how these modular components fit into everyday routines.

eufy Smart Lock Batteries Lineup at a Glance

The Models in Detail

01 12000mAh Rechargeable Battery for eufy Security 12000 mAh ultra-large capacity rechargeable battery ensures long time

Check price on Amazon Our score: 8.0/10

Best for: Heavy-traffic S330 and S230 lock owners

Pros

• High 12000 mAh capacity
• Wide operating temperature range
• Includes USB charging cable
• Multiple circuit safety protections

Cons

• Third-party manufacturer rather than OEM
• Listing specifies lead acid composition

The 12000mAh Rechargeable Battery for eufy Security from FancyBuying provides an aftermarket alternative engineered specifically for high-draw hardware such as the eufy Security S330 and E330 3-in-1 video smart locks, alongside the S220, S230, S231, and Smart Drop delivery boxes. According to its specifications, this model T8520S cell outputs 3.7 volts at 44.4 watt-hours, utilizing an upgraded thickened battery cell structure rated at 12000 mAh to deliver uninterrupted power across a wide temperature window of -22 degrees Fahrenheit to 158 degrees Fahrenheit. Built as a direct drop-in module, the battery allows homeowners to recharge the unit using a 5V/2A input via the included USB charging cable without removing the smart lock assembly from the door.

In terms of hardware architecture, the listing specifies a lead acid cell composition accompanied by multiple circuit safety protections covering overcharging, excessive power draw, short circuits, high temperatures, over-voltage, and battery PTC safeguards. With physical dimensions measuring 3.94 by 2.83 by 1.57 inches, it slides directly into the lock chassis. For users managing a high-traffic eufy fingerprint door lock installation, this third party eufy battery provides an accessible backup that eliminates security downtime during routine charging cycles.

This battery suits busy households operating older or video-integrated deadbolts like the T8520 and T8531 series who want maximum uptime from an aftermarket pack with an included charging wire. However, users seeking genuine OEM factory parts manufactured directly by Anker, or those looking for standard lithium-ion chemistries, will find the official eufy T85Z0 pack a better match for their preferences.

02 eufy Rechargeable Battery for eufyCam S4 10,000 mAh Capacity compliments each advanced feature

Check price on Amazon Our score: 9.6/10

Best for: Shoppers wanting authentic OEM Anker power

Pros

• Official genuine eufy factory pack
• Powers S330 locks and eufyCam S4
• Quick swap without dismounting hardware

Cons

• No direct onboard USB-C port
• Standard 10,000 mAh capacity

The eufy Rechargeable Battery for eufyCam S4 is an official factory accessory manufactured by Anker under model number T85Z0. Designed to deliver authentic manufacturer reliability, this eufy rechargeable battery features a 10,000 mAh capacity paired with standard lithium-ion cell chemistry. The listing specifies broad cross-device compatibility, powering not only the eufyCam S4 camera but also key smart lock models including the S330 3-in-1 Video Smart Lock, E330 Video Smart Lock, Smart Lock S230, Smart Lock E31, and the Smart Drop delivery parcel vault.

Because this unit is an authentic first-party pack, it maintains strict factory physical tolerances, measuring 4.4 by 3.1 by 0.9 inches in a matte black finish. The listing highlights the quick-swap design, enabling homeowners to pop open the lock housing and trade out a depleted pack for a fresh one in seconds without moving or dismounting the exterior deadbolt hardware. When keeping an active eufy door lock with camera operational around the clock, having an identical OEM spare avoids fitment uncertainties and maintains smooth mechanical engagement with the internal lock latch.

This original eufy s330 battery is ideal for homeowners who insist on certified brand components backed by Anker’s 12-month manufacturer warranty. On the other hand, shoppers who require direct onboard USB-C charging ports or who own the newer FamiLock hardware series will need to look past this model toward specialized FamiLock units or alternative third-party form factors.

03 eufy Security Rechargeable Battery for FamiLock eufy Rechargeable Battery for FamiLock S3, FamiLock S3 MAX, Smart Lock E40

Check price on Amazon Our score: 9.2/10

Best for: FamiLock S3 and E40 deadbolt owners

Pros

• Genuine eufy factory replacement
• Generous 18-month warranty description
• Precise FamiLock internal fit

Cons

• Listing does not specify mAh capacity
• Incompatible with older S330 locks

Built specifically for the brand’s contemporary smart entry devices, the eufy Security Rechargeable Battery for FamiLock serves as the authentic OEM power source for the FamiLock S3, FamiLock S3 MAX, and Smart Lock E40. Carrying official model number T85Z1, this genuine eufy famillock battery features lithium-ion chemistry delivering a regulated 3.85 volts. The listing specifies item dimensions of 3.7 by 2.64 by 0.87 inches with a total battery weight of 249.19 grams, ensuring precise physical integration with the slim internal compartments of the FamiLock door mechanisms.

Unlike older lock batteries that share modular compatibility with external cameras and parcel boxes, this unit is engineered exclusively around modern entry locks. The listing notes that a single nonstandard lithium-ion battery is included, backed by an 18-month warranty description. Because modern video deadbolts perform facial recognition, continuous fingerprint scanning, and Wi-Fi video streaming, maintaining a dedicated OEM power cell guarantees proper electrical communication with the lock’s internal power management sensors without triggering false low-battery alerts.

This authentic eufy smart lock replacement battery suits homeowners running FamiLock S3 or E40 hardware who prioritize exact OEM mechanical alignment and extended 18-month warranty protection. Conversely, users who need a battery for older S330 or S230 video deadbolts cannot use this model due to differing chassis dimensions, and must select the T85Z0 or compatible S330 packs instead.

04 NASTIMA S330 Security Rechargeable Battery

Check price on Amazon Our score: 9.2/10

Best for: S330 users wanting visual charge indicators

Pros

• Dual-color LED charging indicator
• Includes 30cm USB charging cable
• Grade A+ cell construction

Cons

• Third-party non-OEM manufacturer
• Incompatible with FamiLock hardware

The NASTIMA S330 Security Rechargeable Battery, produced by Quanzhou Melasta New Energy Co. under model number EF37-LI1050-NA, provides a dedicated replacement option for eufy video deadbolts. Formatted for complete compatibility with the eufy S330, S230, S220, E330, and S231 3-in-1 locks along with the Smart Drop container (matching model references T8520, T8520S, T8520J11, T8531, and T8520T11), this pack delivers a rated capacity of 10500 mAh at 3.7 volts. The listing emphasizes that swapping this pack directly replaces the original battery without requiring any tools.

A notable feature detailed in the product data is the dual-color LED charging indicator integrated into the unit. When connected to a standard 5V/2A power source using the supplied 30-centimeter USB charge cable, the LED flashes green while actively charging and turns to solid green once the 10500 mAh capacity is fully replenished. Internally, the battery utilizes Grade A+ cells paired with safety systems preventing over-charge, over-discharge, short circuits, and over-temperature situations. The unit weighs 170 grams and measures 2.97 by 2.32 by 0.83 inches (77.5 by 59 by 21 mm), maintaining a lightweight and compact footprint.

This aftermarket pack is ideal for users with S330 or S230 smart locks who want visual confirmation of charge status via a dual-color LED and a generous 35-day return backing alongside 1 year of after-sales service. However, households that have transitioned to the newer FamiLock chassis or who prefer an OEM Anker branded battery will find this unit incompatible with their physical lock chambers.

05 15000mAh Battery for Eufy FamiLock S3

Check price on Amazon Our score: 9.6/10

Best for: FamiLock owners seeking maximum runtime

Pros

• Massive 15000 mAh capacity
• Direct USB-C charging port
• Four-LED charge level display
• Rated for 500+ recharge cycles

Cons

• Third-party aftermarket replacement
• Exclusively fits FamiLock models

Expanding power options for newer deadbolt releases, the 15000mAh Battery for Eufy FamiLock S3 from Burflo represents an aftermarket alternative designed specifically for the FamiLock S3 and FamiLock S3 MAX. Carrying model number HB-T85Z1, this lithium-ion battery provides a high stated capacity of 15000 mAh running at 3.85 volts. The listing states complete compatibility with original part numbers including T85Z1, HB-T85Z1, 1lCP7/61/79-3, T85V0, and E85V0JY1, allowing owners to slide the pack into place without hardware modifications.

The listing highlights a convenient direct USB-C input on the battery housing, turning the cell into an independent charging unit that can be replenished with a power bank, laptop, or standard wall adapter. A built-in four-LED power meter displays real-time recharging progress, eliminating guesswork about remaining energy levels. Furthermore, the manufacturer specifies over 500 recharge cycles alongside internal safeguards against overcharging and short circuits, while maintaining consistent voltage delivery to ensure the smart lock responds instantly to motorized latch requests and remote unlocking commands.

This pack is tailored for busy households utilizing a FamiLock S3 setup that experiences heavy daily traffic and requires maximum days between battery charges. Nonetheless, property owners using legacy deadbolt models such as the S330 or S220 cannot utilize this battery, as its form factor and voltage profile are customized exclusively for the FamiLock and E40 door lock architecture.

06 Lesaps 1-Pack Replacement Battery for eufy Features a high-capacity 7000mAh cell for extended runtime

Check price on Amazon Our score: 9.0/10

Best for: eufy E340 video doorbell owners

Pros

• Engineered for E340 video doorbell
• Direct Type-C charging port
• Includes specialized housing removal pin

Cons

• Does not fit smart door locks
• Modest 7000 mAh capacity

Rounding out the entryway power ecosystem, the Lesaps 1-Pack Replacement Battery for eufy targets video monitoring hardware directly at the doorframe. Manufactured by Dongguan Hongbo New Energy Technology Co. under model number HB-E340, this lithium-ion battery is engineered exclusively for the eufy Security Video Doorbell E340. The listing specifies a 7000 mAh capacity operating at 5 volts direct current with a 2-amp input rating, built to extend operating intervals between recharging cycles on dual-camera doorbell fixtures.

Convenience is a major focus in the listing data, which specifies an onboard USB Type-C port that allows standalone charging without mounting the unit to external docks. A two-color LED indicator glows red while the cell is receiving power and shifts to solid green when charging is complete. The package includes a specialized removal pin to unlock the doorbell housing effortlessly, an accompanying USB-C charging cable, and a user manual. An intelligent control chip provides protection against overcharging and overheating, backed by a 30-day free return policy and a one-year limited warranty. For property managers deploying a eufy doorbell cam beside their deadbolts, keeping this modular pack charged ensures zero blind spots at the doorstep.

This battery is specifically for homeowners with the E340 Video Doorbell who need a rotating backup cell to avoid security downtime while charging. It gives way completely when shopping for actual door locks, as its 7000 mAh form factor and latching structure will not fit any eufy smart deadbolt or Smart Drop parcel box.

Matching a Model to Your Setup

• For high-traffic S330 or S230 video deadbolts requiring maximum aftermarket capacity: Choose the 12000mAh Rechargeable Battery for eufy Security to leverage 12000 mAh of stored energy and wide operating temperature thresholds.
• For owners of the eufyCam S4, S330, or Smart Drop desiring factory OEM parts: Select the eufy Rechargeable Battery for eufyCam S4 to maintain strict Anker manufacturer specifications and 10,000 mAh capacity.
• For new FamiLock S3, S3 MAX, or E40 smart lock installations seeking official components: Pick the eufy Security Rechargeable Battery for FamiLock to ensure factory-calibrated 3.85V power delivery and an 18-month warranty.
• For S330 or E330 owners who want visual LED charge indicators on an aftermarket cell: Go with the NASTIMA S330 Security Rechargeable Battery for its clear flashing-to-solid green LED charging status and Grade A+ cells.
• For heavy-use FamiLock doors needing long runtimes and direct USB-C recharging: Opt for the 15000mAh Battery for Eufy FamiLock S3 to gain high-capacity 15000 mAh reserves and 4-LED progress tracking.
• For homeowners running the dual-camera E340 video doorbell: Choose the Lesaps 1-Pack Replacement Battery for eufy to swap doorbell power instantly using the included removal pin and USB-C port.

Before You Buy

Checking physical dimensions, model numbers, and pin layouts before purchasing a eufy door lock battery prevents frustrating setup delays at your front door. Smart lock housings are engineered to millimeter-level tolerances, meaning batteries built for the S330 lock family will not slide into the narrower battery tracks of the FamiLock S3 or E340 doorbell. The Amazon listings do not include AC wall power adapters in any of these packages; while USB cables or removal pins are provided in select kits, you must supply your own 5V/2A standard wall brick to charge the packs.

In addition, several technical nuances are omitted across the retail product listings. The listings do not specify individual cell recharge times from empty to full, nor do they clarify exact operational longevity in terms of days or lock motor cycles, since frequency of use, motorized deadbolt friction, and Wi-Fi signal strength dramatically alter drain rates. For the official FamiLock battery, the listing does not specify the exact milliamp-hour capacity rating, stating only its 3.85-volt electrical profile. Always verify your lock model number stamped on your deadbolt’s interior escutcheon before ordering an extra pack.

FAQ

How do I know which battery fits my eufy lock?

To determine which battery fits my eufy lock, inspect the model label located beneath your lock’s interior battery cover or inside your eufy Security app device settings. Deadbolts marked S330, S230, S220, E330, or model codes beginning with T8520 utilize standard 10,000 to 12,000 mAh horizontal packs like the T85Z0 or compatible aftermarket equivalents. Modern locks labeled FamiLock S3, FamiLock S3 MAX, or E40 require the taller, specialized T85Z1 battery profile. Video doorbells such as the E340 use their own proprietary form factor and will not accept deadbolt batteries.

Can I charge a eufy door lock battery without removing the lock from the door?

Yes, every battery listed in this guide allows you to recharge without dismounting the smart lock assembly from your entryway. All models feature quick-release or slide-out designs where you simply remove the lock’s interior faceplate, pull out the depleted power cell, and connect it to a compatible charging cable. If you keep a second charged pack on hand, you can swap it into the lock in seconds, maintaining unbroken security at your entrance.

What is the difference between genuine eufy batteries and third-party options?

Genuine eufy batteries are manufactured directly by Anker or eufy to match the original factory tolerances, operating voltages, and warranty guidelines of your smart hardware. A third party eufy battery is produced by independent battery manufacturers like FancyBuying, NASTIMA, or Burflo. While third-party options often introduce practical conveniences such as higher stated capacities, dual-color LED charge lights, or standalone USB-C charging ports, official packs guarantee exact structural fit and manufacturer testing standards.

Can I use an E340 doorbell battery inside a eufy smart deadbolt?

No, the battery designed for the eufy Video Doorbell E340 is physically and electrically incompatible with eufy deadbolts. The E340 uses a compact 7000 mAh rectangular cartridge engineered specifically for doorbell brackets and requires an included release pin to eject. Smart locks like the S330 or FamiLock S3 feature wider internal deadbolt chambers and distinct electrical contact alignments, making cross-category battery swapping impossible.

What should I do if a third-party battery shows a different voltage or capacity?

Always ensure the battery voltage closely matches your lock hardware requirements. For instance, S330-compatible units operate around 3.7 volts, while FamiLock packs specify 3.85 volts. Minor variations in advertised capacity, such as 10,000 mAh compared to 12,000 mAh or 15000 mAh, represent differences in total energy storage rather than electrical output. As long as the physical form factor and connection pins match your specific lock model series, an upgraded milliamp-hour rating simply extends operating runtime between charges.