Here is what I found in the install manual, page 2-2.
The EMS-D10 system-wide power requirement is 8 watts typical and 10 watts maximum. On a 12-volt system, this translates to about 1 amp of maximum current draw. On a 24-volt system, this translates to about 0.5 amps maximum current draw. Normally, a 2-amp circuit breaker or fuse is sufficient.