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How to Recharge a BMW E90/E91 Key Without Opening It

Model: BMW Serie 3 E91, E90, E92 - Years 2005-2013
Part: Key

BMW keys recharge while in use, and it takes 30 hours for a full charge. If you leave the key in the car without using it, the key will discharge, which is a hassle because the key cannot be opened. Our YouTuber conducted an experiment by looking inside a BMW key and found that the battery is soldered to the CPU, making it non-replaceable. He then created a small device; a sort of homemade charger that someone with electronics knowledge can replicate, to charge the key without placing it in the vehicle, and in just a few hours; much less than the 30 hours required under normal circumstances. It's worth a try.

Updated on 22 June 2026 by ScegliAuto

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