getting a second (and third) remote entry solution

[oldskewel]

Originally Posted by Effduration

Hey Oldskewel, Is there a convenient way to charge key fobs outside of the car?

I like the idea of used genuine key fobs as extra remotes, but I remember reading that if they are hanging on a key chain they aren't close enough (or are not positioned correctly) to be charged by the induction charging of the ignition.

I have heard that certain phone and toothbrush chargers can charge our fobs, but haven't see a definitive solution.

I analyzed all that when I had the fobs opened up when I put in new rechargeable batteries, covered in this thread:

https://xoutpost.com/bmw-sav-forums/...r-options.html

Specifically on the recharging ...
Prior to doing the surgery, my solution was to masking tape all 4 of my fobs (one original diamond key in the ignition, plus the 3x eBay fobs) together, with the diamond key in, and the other fobs close enough to optimal position to take in the charge. I'd put them in the ignition, with the key to ACC, with the car on a battery charger so it would not run down, and overnight the fobs would be well charged. I found I could easily go a year or more before I needed to repeat that.

But when I had things opened up, I thought I'd try to experimentally verify which of the various chargers would actually work, of course wanting to use a charger I already had.

Post #14 in that thread: https://xoutpost.com/1183412-post14.html

Post #19 https://xoutpost.com/1183483-post19.html

I measured the fob battery voltage in the presence of my toothbrush charger (failed to charge), and then my son's iPhone charger, which worked perfectly, steadily ticking up at about a mV per minute, leading to an end to the experiment. So that's what I do now to keep them maintained without needing to do the more manual solution above.

As said there, the iPhone charger is a Belkin F7U027
https://www.amazon.com/Belkin-Boost-...075M59ZB7?th=1
https://www.belkin.com/us/support-ar...icleNum=274455

with some details in there about the green light on the charging pad. If not measuring the fob battery voltage, I would think it was not working, based on the green LED.

BTW, @workingonit had asked me earlier about where these fobs were on eBay. From a quick look, I could no longer find used Genuine BMW fobs on there, which were plentiful back in 2014 when I got mine. I can see that these NEW non-OE ones are so cheap, do the job, and have the convenience of replaceable batteries, so maybe that led to the old ones going away. But the BMW ones are pretty amazingly built on the inside, so I'm happy I got mine when I did.