Got a new to me bass boat. 200 optimax motor. Every kind of freakin light, pump, aerator and accessory hooked to the cranking battery. Cranks fine as long as the accessories power switch is left OFF. Turn it on and you get maybe 2 cranks before she's done. A little research shows i need a group size 31 deep cycle battery w/ at least 800cca. There ain't one within an hour of me. I can order one on amazon...but do i trust that? Whatta yall do?

Is your battery actually bad? I'd just go to Craig's in Decatur and get the biggest deep cycle they have. How hard would it be to convert to a 2 battery system?

Really no more room back there...there's already 4 batteries back there. :0 I had forgotten about Craig in decatur. I'll see what they have!

Spend the money and get an Odyssey. I have 4 in my boat and last weekend my coangler says to me at 2 oclock. "What kind of batteries do you have? I have never been a boat that did not slow down by the end of the day. "

My boat was doing the same thing yours is. My battery load tested fine, mulitple times, with multiple testers. I seriously contemplated getting Odyssey batteries after reading Ben's reviews and may wish that I had, but I didn't. We buy a decent amount of batteries at our shop and get great prices at one of our local parts stores. I ended up getting a Deka AGM dual purpose. Running 3 graphs all day, it never drops 1/10th of a volt, going by the volt meter on the one graph that I have that function enabled on. Same graph with my old battery would show up to a 3 volt drop in 6-7 hours of fishing. I'm not going to recommend getting one, or not getting one yet. Too soon to tell. To me the proof in the pudding for a battery is how it performs it's second and third year. Having said that, I'd definitely recommend going with an AGM of some sort. They are built to take the vibrations that they will encounter in a boat. I learned that while researching the Odyssey batteries.

Why are they all hooked to cranking battrey does it not have any more battrey

on mine, everything goes to a fuse panel, then to a battery thru 1 connection. Going to the trolling motor bats isnt an option since its a 36v. Im guessing the aerators and graphs just eat on batteries...and i really dont know how old that innerstate is.

You've got 3, 12 volt trolling batteries. You can hook anything in your boat to any of those batteries, just hook the hot and ground wire to the pos and neg terminal on ONE battery. That will just give you 12 volts.

Everything is hooked to the cranking battery because that's SOP for wiring in boats. Only the TM hooked to those batteries. Cuts down on electrical interference with graphs.

Electronics don't really eat batteries. Pumps do eat them(areators and bilge). Do you charge after every trip? Doesn't Decatur have a Walmart? I'd buy the biggest deep cycle they have for a cranking battery. Make sure you charge all batteries after each trip, this extends their life. if you use one of the TM batteries for anything, make sure it isn't the fishfinders. The next thing I'd recommend is a 24 volt trolling motor. I owned several 36 volt ones and it is tiresome keeping up with three TM batteries. You really don't run on 36 high that much unless you are fishing in heavy current. Good Luck

Gman I have a battery checker that will tell you the CCA if it is fully charged. Holler at me Monday and we will see what it says. Perch Craigs in Decatur has better batteries for less money than Walmart. Buy all my batteries there.

I'm not familiar with what is and isn't in Decatur anymore. I'm sure you know best Dave.

I got one on the way. There was a big thread on bbc when i googled 200merc optimax specs. Someone did a lot research for folks on there. I settled on a Banshee g31, or something like that. 900cca and 190min reserve. Thats 60min more than comes with the optima bats...and $100+ less. Thanks for the input. I still dont know if something is “draining” it, or if the battery is just weak. Fur, i sure appreciate you info. I hate all lectricity and know zero about it.

My Helix 9 does. I bought a deep cycle battery made for electric wheelchairs and ran my Helix off it.