We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Black rectangular Li-ion battery pack for smart door lock

KingSener

KingSener YC04E 4200mAh 7.4V standard battery

SKU CH-XB4S-FJES2 MPN YC04E

A 7.4 V, 4200 mAh lithium-ion replacement battery built for smart door locks, matching original dimensions for a direct fit

  • Battery voltage rating7.4 V
  • Battery capacity4,200 mAh
  • 4200mAh capacity powers smart door locks for extended periods
  • 4V lithium-ion chemistry delivers stable voltage output
  • 100% compatible replacement matches original battery dimensions
  • High-quality cells with PCB protection ensure reliable performance
  • New condition guarantees full design capacity from first use

Replacement battery for smart door locks

This KingSener YC04E is a lithium-ion replacement cell built for smart door locks that require a 7.4V pack. It ships new and matches the original dimensions so installation needs no modification. Buyers who need a different voltage or a larger capacity should look elsewhere.

Voltage and capacity match

The single specification that decides fit is the 7.4V 4200mAh rating; the lock must accept this exact voltage and the connector must follow the P-P+C+C- pinout. If the original pack uses a different voltage or pin arrangement this unit will not work.

Thermals and power draw

Li-ion chemistry runs cool during the low-current draw of a door lock and produces no audible noise. The supplier advises a full charge and discharge cycle two or three times at first use and recommends storing the pack above 80% charge if it is removed for a month or more.

How it compares

Measured against everything we stock in Household Batteries & Chargers, at today’s prices. Recalculated every night.

Price $21.99
Pricier than about 80% of the 10,440 comparable items (median $10.99).

Specifications

Product
Brand nameKingSener
Model nameYC04E
Part numberYC04E
Power
Battery voltage rating7.4 V
Battery capacity4,200 mAh

Questions about this item

How long will the 4200mAh capacity keep a smart door lock running on a single charge?

The 4200mAh rating means the battery can deliver that amount of current for one hour; actual runtime depends on the lock's power draw and how often it operates.

What does the 7.4V voltage mean for compatibility with my lock?

The 7.4V output matches the original battery specification; the lock must be designed for this exact voltage to operate safely.

Will the P-P+C+C- pin layout fit my existing battery compartment?

The connector uses a P-P+C+C- pin arrangement; it will fit only if your original battery has the identical pinout and physical connector shape.

More in Household Batteries & Chargers

Similar items