If you are running your EM-11 off a 12V battery,
use a heavy duty (5-10 Amp) fused power cable
The EM-11 draws up to 5 Amps at 12V when slewing in the Southern Hemisphere. Beware of inexpensive 12V power lines with 2A fuses.
Be aware that there is different amperage use by the EM-11 during 150X slewing when it is operating in Northern hemisphere and when it is working in the Southern hemisphere. If you are using the 12V 12A Takahashi power supply, you won't have any problems. If you are in a remote location running off a 12V battery you need to be aware of different power use during slewing and your power line fuse.
When operating in the Northern hemisphere, the EM-11 tracks and performs high speed slews (125X) never consuming more than 2 amps of power. If you have a fused cigarette lighter style power line (e.g., sold by Radio Shack) between your battery and mount with a 2 Amp fuse, you'll probably never have any problems. However, when operating in the Southern hemisphere with the RA motor running in reverse direction from Northern hemisphere, the high speed motors running draws between 2 and 5 Amps. Make sure you have a heavy duty power line that has at least a 5 Amp fuse. The 2 Amp fuse will blow in the middle of a high speed slew in the Southern Hemisphere.