Garmin Echo 300 vs 550

Got a question, I own both of these FFs and I installed the 300 in my yak.  The 550 is supposed to be for my boat.  I'm staring for think I won't be taking my boat out as much as my yak and therefore replacing the 300 with the 550, but I'm worried about the extra drain on the battery.  I currently have a 12v/9amh battery.  The 550 pulls and extra 200 watts, but the resolution can't compare.  Thoughts on the battery life, be ok not ok?

One last thing the extra power is that a function of the head unit or the transducer, would like to leave the ducer installed there. They look identical between the units

Thanks!

Not a direct answer but this may help.  I recently installed a 400C in my yak with an 8AMH sealed lead acid battery.  After a full day on the water, I still had plenty of battery left for at least another full day.  I don't know how this would compare to the 550 but the 400C is a color display.

That helped a lot, looked up the specs and the 400 is a 500w FF as well.  Guess I'll be okay, thanks!