How much current do small USB-WiFi routers draw?

Jbeale reviewed how much current small USB WiFi routers draw. His intent is to connect them to the Raspberry Pi which can only provide 140mA over the USB port. It turns out that from Internet connectivity the routers draw under 100mA, but if used in high speed LAN operations the current draw jumps over R-Pi’s threshold.

I recently compared two small USB Wi-Fi N adapters from eBay. Both devices easily connected my WinXP laptop to a Linksys WRT160Nv2 router, showing excellent signal strength and a 72 Mbps link speed. Interestingly, both adapters stayed under the 100 mA limit while handling my DSL broadband speed. However, when connecting to a machine on the LAN, the speed increased, and the current draw exceeded 150 mA—more than an unmodified RPi USB port can reliably supply. So, either of these devices should work perfectly for internet browsing on the RPi without an external power supply but may become unreliable for heavy LAN use, such as high-bitrate video streaming. If your broadband speed is faster than mine, even regular web browsing might cause overcurrent issues.

Via the forum.