BMW E39 and E46 keys (Commonly Known as Diamond Keys). BMW E90/91/92/93 as well as many BMW key fobs from the early 2000's. (there are many guides on how to do this on the internet).
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【TO】5 PCS CR123A Battery Box Cover For PCB DIY Plug-in CR123A Battery Holder 16340 Battery Box LIR123A Battery Storage Box
Aliexpress UK
BMW Mini KEY FOB Battery. Battery Capacity: 20mAh. Battery Size Code: 2020.
eBay
1PC Battery Storage Rack Battery Mount Holder Portable Storage Rack Basket Bracket Holder For Makita 18V Battery (NO Batteries)
Aliexpress UK
BMW E39 and E46 keys (Commonly Known as Diamond Keys). BMW E90/91/92/93 as well as many BMW key fobs from the early 2000's. (there are many guides on how to do this on the internet). BMW had a different shape pcb leg mount put on the there batteries (which you cant buy) but this just requires a little modification.
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1-5PCS Battery Holder Battery Holder Compatible for Dewalt 14.4-18V Battery Mounts Dock for DCB200 DCB201 DCB202 （No Battery)
Aliexpress UK
BMW E39 & E46 Diamond Keys. A cheaper alternative than buying direct from BMW. BMW E90/92 & 93. We aim to match the lowest price for all our products. Large orders will require a signature. 100 Laiton Rondelles Rond Trou Bombé Horloge Montre Réparation Parts Clockmaking.
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Battery Storage Organizer Small Battery Keeper Wall Holder Battery Dispenser Container For 10AAA & 10AA Batteries-AA & AAA Combo
Aliexpress UK
For BMW E90 E91 E92. For Ford Galaxy (CA1) 2010-2015. Car Remote Keys. Car Key Shells. Battery Capacity:50mAh. For BMW Mini Cooper 2007-2014. Battery Size Code:2020. Battery Technology: Lithium Vanadium Pentoxide.
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Large capacity 18650 battery 3.7V 9900mAh rechargeable liion battery for Led flashlight Torch batery litio battery
Aliexpress UK
This fits Most BMW 3, 5, 7 and E46 series (check it requires the battery with pins and not the CR2032). Battery Capacity: 20mAh. Battery Size Code: 2020.
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Digital Battery Tester LCD Display AAA AA Button Cell Battery Checker Volt Measure BT189 Battery Capacity Indicator Meter Tools
Aliexpress UK
BATTERY VL2020. For BMW E81 E82 E84 E87 E88 E89. For BMW E90 E91 E92. For BMW E70 E71 E72. For Ford Galaxy (CA1) 2010-2015. For BMW 1 3 5 7 Series X5 X3 Z3 Z4 E46 E39 E60 E63 E53. For BMW 1 Series 2004 - 2013.
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1300mAh 3.7V Li-ion Rechargeable 16340 Batteries CR123A Battery + LCD 4-slot Charger For 16340 CR123A Battery Flashlight Battery
Aliexpress UK
BMW E90/91/92/93 as well as many BMW key fobs from the early 2000's. (there are many guides on how to do this on the internet). BMW E39 and E46 keys (Commonly Known as Diamond Keys).
eBay
50PCS Spring Steel Battery Contact Battery Insert 18650 Battery Clip 18650 Battery Holder
Aliexpress UK