DIY: Replacing the battery for an e90 - BMW 3-Series (E90 E92) Forum
12 Volt Battery for the Razor E90 Accelerator, Power Core 90, Power Core E90 (Versions 1-2+), & Power Core E90 Glow (Versions 1+) - Monster Scooter Parts
Pack of 10 Energizer E90 N Size 1.5V Alkaline Battery - Bulk Pack - with FREE Clear Battery Storage Holder Case
Amazon.com: Energizer E90 N Alkaline 1.5 Volt Battery (6-Pack) : Health & Household