Bought a 12v Terrova for my old tracker pro crappie and I’m considering adding a spare battery in case the spot lock function is a huge drain on the battery. Would there be any advantages to putting the extra battery in the bow?

Best thing - make sure both batteries are identical - buy two the same and use the old one for electronics maybe. Then connect them in parallel...It'll still be 12v - just double the AH. That way you'll have the advantage of a second battery to power the Terrova without having to switch battery connections in the middle of the lake.

Thanks for replying. I am going to wire them in parallel but with the added weight and the tight fit I was just wondering if putting the 2nd battery up front would be a good idea. 

43 minutes ago, Just David said:

Thanks for replying. I am going to wire them in parallel but with the added weight and the tight fit I was just wondering if putting the 2nd battery up front would be a good idea. 

Well, when wiring in parallel you want the batteries as close to each other as possible. So it's either both up front or both in back with LONG cables (6 gauge...8 gauge minimum) running to the TM.

Hadn’t thought of both up front. That would be really convenient for me. Thank you. 

depending on how big your outboard is, putting both batteries up front might affect getting on plane and top speed.