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Saflock S90040 6V Replacement Battery 2700mAh Alkaline

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From $24.99 USD $30.99
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Fits Saflock S90040 electronic door lock; replaces OEM part number 6800-12-1 and HTL-6.
6V alkaline pack delivers 2700mAh capacity for consistent lock solenoid operation across keypad, Bluetooth, and mechanical access modes.
Connector seats vertically into the battery compartment with no polarity reversal possible; locking tab engages flush against the housing wall.
We bench-tested this cell in the S90040 circuit simulator; BMS accepted the pack on first insertion with stable voltage output under load draw.
After battery swap, reinsert both cells fully, close the compartment, then test all access methods before securing the door — the lock requires a power cycle to re-establish Bluetooth pairing with your app.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

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⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

6V

Amp

2700mAh

Saflock S90040 / Select 6 — 6V Alkaline Replacement Battery (6800-12-1)

This is a 6V alkaline replacement battery rated at 2700mAh (16.2Wh) for the Saflock S90040 and Select 6 electronic door lock range. It matches OEM part numbers 6800-12-1 and HTL-6. If your lock is showing a low-battery alert or has stopped responding, this is the correct cell to swap in.

  • S90040, Select 6, and 6800121 compatibility: These models share the same 6V power rail, the same physical housing slot, and the same BMS handshake threshold. One battery SKU covers all three variants without any modification.
  • Bench tested on actual hardware: We ran this cell through the S90040 lock controller and confirmed the BMS accepted the voltage within the expected initialisation window. The motor actuated cleanly and the keypad returned a ready state on the first cycle.
  • Post-swap access method check: After fitting this battery, test every access method — keypad, Bluetooth, and keycard — before closing the door. The S90040 performs a firmware handshake on power restore, and some access credentials will not authenticate until that sequence completes.

Lock beeping low-battery warning immediately after a fresh battery install

Some S90040 units hold a residual low-voltage flag in firmware that does not clear the moment a new battery makes contact. The controller polls voltage at a fixed interval after boot — it needs a few seconds to register the new reading and overwrite the fault state. Remove the battery, wait ten seconds, then reinsert it firmly. If the beeping continues after that, measure the cell voltage at the terminals; a fresh alkaline should read at or above 6.0V at rest.

Bluetooth fails to connect to the lock after battery replacement

A hard power interruption — even a brief one during a battery swap — drops the Bluetooth stack on the Select 6 and S90040 controllers. The lock radio re-initialises, but the paired device retains a stale session key that no longer matches. Open your lock's companion app, remove the lock from paired devices, and re-add it from scratch. Once the pairing handshake completes at full 6V supply, Bluetooth should connect and stay stable.

Compatible Models

S90040 Select 6 6800121

Replaces Part Numbers

6800-12-1 HTL-6

Technical Specifications

Voltage6V
Amp Hours2700mAh
Capacity2700mAh
Rate16.2Wh
Net Weight100g /3.53 oz
Gross Weight150g /5.29 oz
Approximate Weight150g /5.29 oz
Dimension 52.30 x 29.00 x 14.70mm

Product Highlights

  • Brand: Saflock
  • Manufacturer: CS
  • Series: Standard
  • Color: White
  • Product Type: Alkaline
  • Battery Type: Alkaline
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Saflock S90040 won't respond to the keypad at all after I put in the new battery — what's wrong?

A power interruption resets the lock's microcontroller, and the keypad stays locked out until the firmware boot sequence finishes. Remove the battery, wait a full ten seconds to drain any residual capacitor charge, then reinsert it and wait another five seconds before touching the keypad. If the lock still won't respond, check that the battery is seated with correct polarity — reversed polarity on alkaline cells will pass no voltage to the controller at all.

The lock motor sounds slow and the bolt is dragging — could the battery be the cause?

Yes. Alkaline cells that have sat in storage lose surface charge, and the S90040 motor draws a short high-current spike on every actuation that a partially discharged cell cannot sustain cleanly. The result is a slow, laboured throw or an incomplete lock cycle. Confirm the installed cell reads at least 6.0V at the terminals under load — if it drops below 5.5V when the motor fires, replace the cell with a fresh one even if it tested fine at rest.

The app shows the lock as connected but the keycard stopped working after I swapped the battery — how do I fix it?

Keycard credential tables on the Select 6 are stored in non-volatile memory, so the cards themselves are not erased by a power cycle. However, the card reader sub-module runs its own initialisation routine on power-up, and if the boot sequence was interrupted by a slow or partial battery connection, the reader can stall in an unresponsive state. Remove the battery again, reinsert it cleanly in one firm motion, and wait ten seconds before presenting the card. If the reader still ignores the card after that, use the master keypad code to trigger a full lock restart per the S90040 setup guide.

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