I'm going to be installing one of these on my boat. I was curious how much draw it has for the battery? Should I get a battery separate from the 12V trolling motor battery? If so what kind of battery should I use?

I would wire it to the boats battery.....I have seen no change with mine

You shouldn't be hooking your depth finder to your trolling motor battery. If you don't have a battery to start your motor, the best option is to get a separate battery for the depth finder. You can try connecting the depth finder to the trolling motor battery but it is likely you will have interference every time the trolling motor is running.

Sorry guys... I should have clarified.. I just have a 14' aluminum boat. I will have a 6HP on the back eventually. And a bow mount trolling motor up front. 

 

Do they make smaller batteries for fish finders? I would need it to last 10 hours a charge. 

This is a typical 8Ah battery that will work just fine. You can probably get a couple of days on a charge. They should run no more than about $40. You can get bigger, or smaller.

 

I fish from an Ascend 128T and have a Hook-5.  When I use my trolling motor the fish finder is powered off the trolling motor's battery, with the transducer is mounted on the trolling motor.  I don't get any interference.

 

When the Hook is on my Lure 11.5 I use my XL Milwaukee M12 batteries in a Pelican box.  I get a full day out of one M12 battery.

I think I'm going to just to throw some alligator clips on the end of the power cables and attached to my trolling battery. If anyone advises against this, or has it done with success I'd like to hear any feedback

16 minutes ago, Tony Albanese said:

I think I'm going to just to throw some alligator clips on the end of the power cables and attached to my trolling battery. If anyone advises against this, or has it done with success I'd like to hear any feedback

 

You were already given accurate info.  Do not power it with your trolling motor battery.  Either use the outboard's cranking battery, or purchase a small 12v battery as shown above.  You'll want to also install a 3 amp fuse inline on the positive lead.  You can find all of this at a marine supply store, Radio Shack, and many home improvement/hardware stores.