1. Integrated (Hidden) Battery
Mounted inside the frame (e.g., downtube).
Pros: Sleek design, better weight distribution, theft-resistant.
Cons: Harder to remove/swap; requires bike-specific frames.
Best for: Commuter/city e-bikes (e.g., VanMoof, most modern e-bikes).
2. External (Mounted) Battery
Attached to the frame (e.g., rear rack or downtube).
Pros: Easy to remove/charge, universal compatibility.
Cons: Slightly bulky, less aesthetic.
Best for: Budget/utility e-bikes (e.g., Rad Power Bikes).
3. Rear Rack Battery
Mounted on the rear cargo rack.
Pros: High capacity, easy access, fits any bike.
Cons: Raises center of gravity (less stable).
Best for: Delivery/cargo e-bikes (e.g., RadWagon, Tern GSD).
4. Dual Battery System
Two batteries (e.g., frame + rear rack or dual downtube).
Pros: Doubles range (ideal for touring/off-road).
Cons: Extra weight/cost, complex wiring.
Best for: Long-distance/performance e-bikes (e.g., Riese & Müller, some e-MTBs).
Key Tip: Choose based on range needs, bike type, and convenience!