Originally Posted By: pkunk
Originally Posted By: Quattro Pete
The ones in my bmw keys are rechargeable. They recharge whenever the key is sitting in the ignition. The original lasted close to 15 years, but the battery is not easily replaceable. And of course if you dont use the spare key for a while, it'll go dead.
And cost hundreds for a new key
My Mercedes key have keyless go and they're about $500 from the dealer, the regular keys are about $300. There was some TSB that mentions that dealers should replace the batteries in the fob whenever the customer comes in for service. Some dealers even do it for free. Mine only end up lasting around 6 months or less, I've tried several brands but they all seem about the same, but maybe I should just stop buying them from eBay, they're probably all fakes even with the brand name. But even the one the dealer put in only lasted 6 months so even if they're fakes, they're still lasting as long as the dealer.