Cranking battery help/suggestions...

[Kyle S]

First fishing trip of the year yesterday. Everything started fine at the dock, drove up to one of my favorite creeks a short distance from the ramp and fished for nearly 8 hours. When I went to start up the outboard, my lead acid group 27 interstate battery that came with the boat and is only 2 years old, didn't have enough juice to start my 40 hp mercury. Which left me having to jump it using my trolling motor batteries.

 

My cranking battery provides power to the outboard, 2 lowrance elite Ti 9's (only one of which was on for the entire 8 hours) , live well (which I don't use), nav lights (which weren't on), pumps (which also weren't on)...and I believe that's it. 

 

When the boat is on the trailer at home, all three of my boat batteries, (2) deka GP 31 deep cycle AGM batteries, and (1) interstate GP 27 cranking battery, lead acid stay plugged into my onboard Dual pro 3 bank, 15amp/bank charger.

 

Ive ran this setup for almost 2 full seasons and never had any issues until now.

 

Any advice on what I should do, or change with my setup?

 

Should I get a new, better cranking battery? Or even add a separate battery just for my electronics?

 

[Jig Man]

I doubt that your electronics draw that much though a larger battery with more ccas and rcs would help.  I have had trouble getting any kind of time out of Interstate batteries for the last few years so I have switched brands.

[BayouSlide]

I run the trolling motor nearly fulltime, the big motor very little. Running into the same problem with electronics draw (2 Helix 10s up front running Mega 360 & Mega Live), to the point where I didn't have enough juice to get the motor trim to work at the end of the day. Solved the problem by switching from an Optima D34M to the larger Optima D31M.

[Deleted account]

I would check the wiring, connectors, and battery terminals to rule that out, if it checks out sounds like it's time for a new battery. Might want to check that the charger is working properly too, though that is likely not the cause, you never know. 

[Kyle S]

Thanks for the replies fellas, I'll inspect everything again and make sure it isn't another problem causing it. if not, i guess its new battery time.

[TnRiver46]

I try to never run graphs for several hours straight without cranking up a few times. 

[gim]

I would be surprised if the 9 inch screen is draining a fully charged cranking battery on its own. I think you may have some other slow drawdown going on with that battery. I’ve been using the same cranking interstate battery for 6 seasons  now with a similar application that you indicated, although I do intend to replace it this spring now. I use 27 size batteries.

[GaryH]

3 hours ago, Kyle S said:

Thanks for the replies fellas, I'll inspect everything again and make sure it isn't another problem causing it. if not, i guess its new battery time.

I would run your battery down to a battery shop and have it load tested. Your lowrance only draws 0.9 amps which shouldn’t even phase your battery if it was in good shape. Unless you have something else in your boat that’s draining it down it’s probably battery time. Like @gimruis said I would get a new battery I would also opt. For a dual purpose unless you have the room for a separate house battery.

[slonezp]

First thing I would do is clean the battery terminals and the ring connectors for the charger and motor and whatever else is connected. See how that pans out before doing anything else.

[Kirtley Howe]

Is the battery a sealed battery? If not, check the water level in it.  As others suggested, clean the terminals and cable ends. Check the battery charger to make sure it is working correctly. A friend of mine had one bank of his 3 bank charger partially fail, so it was not charging his primary battery but still charged his trolling batteries just fine. Doesn't happen often, but is a possibility. If everything checks out ok, take the battery in and have it load tested. If it checks good, there must  be a draw down somewhere in the boat wiring that is killing your battery. And I strongly suggest carrying a "jump box" (battery booster) with you on the boat. Jumping from your trolling motor batteries can cause a spark which can cause explosions, and/or fry sensitive electronics. The jump box will not cause sparks if used correctly. Better safe than sorry.