Trolling motor battery

[Kirtley Howe]

The boat is a 15ft. Boston Whaler with a 60hp bigfoot motor and 60lb thrust Great White trolling motor. Listed weight with 1/2 tank gas is right around 1000lbs. Figure 400 lbs in fishermen, and 400 lbs in gear/tackle/batteries, etc.. Total weight should be under 2000 lbs. total. 

 

I have been given a $100 Walmart Gift Certificate. I need a trolling motor battery. (I have a good deep cycle marine starting battery already for starting the outboard motor). Looking on Walmart's website I see they have a group 27DC deep cycle marine battery for around $95.00, that is rated for around 100 amp hours (which seems a bit optimistic to me....I would believe maybe 75 amp hrs. at best) . It is also rated for 750 mca. That confuses me. Nowhere on the battery does it say "Marine Starting Battery", so I would assume that it is a trolling motor/accessory battery, not really a cranking battery. Am I correct about that? And would that battery be sufficient to power the trolling motor for 4 hours or so at 1/2 to 3/4 throttle? The only other draw would be an old depth finder/fish finder that would be used for depth only. The bilge pumps and lights will all be on the starting battery.

 

Also, if someone has experience with the EverStart Walmart batteries, I would like your opinion. I have used their car batteries with no problems but have never used their marine batteries.

[TnRiver46]

DC stands for deep cycle

 

i like the ever starts. Used one Saturday fished 12 hours and it still had power. 55 lb 12v motor guide  18 ft center console with 50 horsepower 

[padlin]

I used one of the Everstart DC batteries on an old camper, needed more water then an Interstate but it was okay for the $.

 

From my very limited experience a 60 lb trolling motor will burn something like 55 ah at full or about 41 ah at 3/4. So the math says if you really want to run at 3/4 for 4 hrs it’ll consume 123 ah. 

 

 

[Jig Man]

If you want a stronger battery and have room move to a series 29 or 31 battery.

[LonnieP]

I’ve been using Everstarts for several years with no problems. I agree with Jig Man , I’d move up to a group 29 .

[casts_by_fly]

a group 27 is fairly small if you're using it hard.  if you want to be sure, bump up to a 29 or 31.

 

That said, are you sure its a 12V motor?  60 lb thrust is a lot for 12V.  I don't know of a current model that does it (happy to be proven wrong).  The highest I know of on the market now is 55 lb.  You might want to double check if you haven't already.

 

if it truly is 60 lb on 12V, that's a pretty high max current.  I'd agree with Padlin's math.  Also remember that a lead acid isn't usable for the full capacity.  Eventually the voltage will drop low enough that the motor is barely chugging along.  Not the place I'd want to be.  Somewhere around 25% remaining is where it gets bad.

[Kirtley Howe]

The trolling motor is a Great White saltwater trolling motor  made by Motorguide. I was told it is a 60 lbs thrust.  I will have to check the actual motor for the thrust ratings and voltage. It appears that the Great White series of motors has been discontinued. The only one I can find listed is shown as back ordered with no known restock date. I have been trying to find more info on the motor, but have not had much success. The one listed as out of stock is a 109lb thrust, 36V unit. The one I have is an older unit and I don't think it is in that range. I have never actually used the trolling motor, but it does spin freely when hooked up to a 12v battery, and seems to spin pretty quickly, but of course I cannot tell if it has much real thrust by just running it for a minute in open air. If it what I think it is after some research, it is a 55 lbs thrush, 12v saltwater rated trolling motor....not a 60 lbs thrust. It appears that Motorguide only made a 55lbs thrust 12v,  a 75lbs thrust 24v, and a 109 lbs thrust 36v. But as I said, I will need to do more research and actually examine the motor more.

Thank you for the responses on this.

[casts_by_fly]

A 55lb 12V is normal.  That's about as much thrust as you can pull from a 12V battery without melting things down.  If that's the case, then I'd go by what Padlin calculated above.  A group 27 wouldn't be enough for me if you're using the trolling motor a lot.  If its just using it to fish the bank around the edge of the lake then you're fine.  You won't be above a quarter throttle hardly at all, if at all.  That would draw a negligible amount of power.  

[WRB]

I suggest using your gift cert towards 2 each Walmart AGM marine batteries. This gives you the option to have 24VDC wired in series or a large capacity 12VDC wires parallel.

You need a 50 amp circuit breaker regardless.

A Perco battery switch is a good option.

Tom

[Kirtley Howe]

The battery switch/circuit breaker is already installed on the boat. It was there when I got it. The boat was given to me by a friend. He inherited it when his uncle died. My friend does not fish or boat, so he told me I could have it if I came and got it. It came with the boat, trailer, motor, and trolling motor. It also has the deep cycle marine starting battery that was only 6 months old. While the boat was in storage pending settling the estate, someone stole the trolling motor battery(s), the seats, and the electronics. Why they didn't steal the main motor and trolling motor and starting battery is anyone's guess......I replaced the tires on the trailer as they were 8 years old, and though they looked good, I did not trust them. I have not had the boat in the water yet, and won't until early next year. I did run the main motor (it has a hose hook up for service and test runs), and it started and ran fine. I will be doing a service (oil, gear oil, plugs etc) before actually using it. The fuel tank has been drained and flushed, so that is ready to go. It is a 20 gallon plastic tank, so no rust problems to deal with. I got a new fuel line and primer bulb which will go on it when I am ready to put it in the water.