12V Deep Cycle Marine Battery combo hook-up

Hi all. My father recently hung up the float tube and decided to get a 10ft Tracker Topper for himself. All he uses is a trolling motor to putt around with. I just bought him a Garmin Echo 150 FF to rig up, but he doesn't want to have to carry around another battery for the FF if he doesn't need to.
My question...with the 12V Marine Deep Cycle battery to power his trolling motor, (12V, 105Ah), would it be possible to connect both the FF and trolling motor to the same battery without blowing anything?
Mind you he doesn't travel that far to get to his fishing hole and when the anchor is in the water he disconnects the trolling motor to one of the terminals to save power.
Any input from all you DIY-ers would be great. 
Thanks in advance.

You can run both without a problem.  The Fishfinder will draw 1A or less.  My color unit draws about 1/8th of an Amp/Hr.  Make sure to install the recomended in-line fuse for the FF.  What is the amp draw of the trolling motor (or send me the model and I will look it up for you).

 

 No problem supplying power to both motor and FF.  Simply connect the FF according to it's instructions.  Red to (+) black to (-) side of battery, FF should have an inline fuse already, if not, it'll need one, usually on the Red lead.
 That big battery won't even know the FF is connected to it compared to the current draw the motor will be using.

  He may even be able to monitor the battery's voltage throught he FF is it has that option to do so.

Thanks guys. I have plenty of fuses for my FF that he can use. Much appreciated.
FYI...
He has a 30lb thrust Prowler trolling motor, so it shouldn't draw too much power from the battery.

You can hook up both to the same battery. 105ah battery is plenty to handle the motor and the FF. However, your motor may give off noise in the line and interfere with the FF, especially if you have a PWM type motor. You may need some inline filter to filter out the noise. Guess you wouldn't know until you try it.

If the FF does not like the noise from the trolling motor you can always use a much smaller 5 to 10 amp seperate battery for the FF.