Should the car key battery be replaced if it's below 3V?
2 Answers
Car key batteries below 3V should be replaced because the battery has no power left at this point. The basic components of a remote key consist of the following two parts: 1. Transmitter: Composed of a transmission switch, transmission antenna, integrated circuit, etc., containing an identification code storage circuit and an amplitude modulation circuit, with a button-type lithium battery installed on the opposite side of the circuit. The transmission frequency uses radio waves, and the transmission switch sends a signal once per button press. 2. Receiver: After the transmitter sends the identification code using shortwave modulation, it is received by the car's shortwave antenna and enters the shortwave high-frequency amplification processor of the receiver's electronic control unit via a distributor for demodulation, where it is compared with the demodulator's identification code.
I've been driving for over a decade and have encountered car key battery issues several times. The nominal voltage for button cells is 3V - anything below this means replacement is due. Just the other day my key buttons were responding sluggishly, and upon testing showed only 2.8V. While it still worked, performance was already unstable. Once at a supermarket parking lot, the buttons wouldn't respond no matter how much I pressed, leaving me sweating until I had to use the mechanical key. These batteries cost just five yuan each and are extremely easy to replace yourself. My advice: replace immediately when you notice the remote's range shrinking, don't wait for complete failure. Always keep a spare battery in your car - it's a lifesaver when the key suddenly dies at night. Prolonged low-voltage operation can also damage the key's circuit board - trying to save pennies might cost you pounds in repairs.
