Both key fobs on low battery after 8 months?!
Super Member
Joined: Apr 2007
Posts: 633
Likes: 48
From: USA
2006 E320 CDI
So my car started to alert me saying that my key had low battery. So I switched to my spare. A few months in, it's started to do the same. I don't understand how my previous BMW didn't require a battery change in 7 years but my two MB keys won't last 4 months each. I place my keys around 4 metres from my car overnight so I can't imagine it's being drained by the car. Also I only drive around 20 minutes a day. Anyone else had this issue? Could this be a fault or is it a common thing?
Super Member
Joined: Apr 2007
Posts: 633
Likes: 48
From: USA
2006 E320 CDI
Do you have keyless go? If you do and you keep your keys close enough to the car (20 to 30 ft) it will constantly communicate with the car and drain the battery very quickly.
your BMW likely didn't have keyless go (or whatever BMW calls it) thus the battery lasted 7 years.
My previous BMW key battery lasted 8 years 175k miles. My current E350 key lasts about 2 to 3 months with the standard CR2025 battery, or more than 8 months with a slightly thicker CR2032 battery. I keep my key about 10 to 15 ft away from the car.
My spare key is on the other side of the house away from the car and it is still on original battery after nearly 3 years. I use the spare about once every 2 or 3 months.
your BMW likely didn't have keyless go (or whatever BMW calls it) thus the battery lasted 7 years.
My previous BMW key battery lasted 8 years 175k miles. My current E350 key lasts about 2 to 3 months with the standard CR2025 battery, or more than 8 months with a slightly thicker CR2032 battery. I keep my key about 10 to 15 ft away from the car.
My spare key is on the other side of the house away from the car and it is still on original battery after nearly 3 years. I use the spare about once every 2 or 3 months.
