Originally Posted by
TnT
Even if you plan on buying a new one, I would still run it on a separate battery. TM noise is gonna be there and it will "probably" affect your fish finder, even if in a small way. The other thing to consider is a spare battery is always a good thing. I ran mt fish finder and trolling motor off the same battery for a long time with no "noticeable" problems but when I added a spare battery, I hooked the fish finder by itself to it. Thats when I noticed the difference, and I have needed a spare battery a couple of days when the wind was up. Just my 2 cents.