Just how big of a battery do I need?

halfmoa

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Aug 19, 2011
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My 1792 Johnson 65 hp model 65esl72s previously had a 660cca battery attached. The battery has failed. It made it 15 years so I can't say I'm mad BUT that's a bigger battery than my SUV has. So just how big of a battery do I need? I boat during the summer, no breaking ice to get a worm wet on my boat.
 

NYBo

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Oct 23, 2008
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The starting requirements of an outboard that small are modest so even a Group 24 starting or deep cycle battery will do the job. In a pinch, you should be able to pull-start the motor.
 

oldboat1

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Apr 3, 2002
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That said ^^ (agree), I usually buy a biggun. 600 to 700 cranking amps is good. I like to buy deep cycles for any boat use -- think some are marketed as combined starting and deep cycling. When it gets old, I use it in the shop and buy a new one for the boat. There's mixed opinion on use of deep cycles for starting batteries, so may get different opinions. Depending on what boat you run, might want to go to a two battery system if you don't have one -- starter and house battery.

got burned a little on this recently (large deep cycle) because the battery I'm using is physically too big/heavy for what I should have -- need to move it around to put the charger on it, and would rather not do that. So smaller would be better in this particular case (mine).
 

bruceb58

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Mar 5, 2006
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There's mixed opinion on use of deep cycles for starting batteries, so may get different opinions. Depending on what boat you run, might want to go to a two battery system if you don't have one -- starter and house batter
Unti I put AGMs in my boat, I used these "deep cycle" batteries to start a 7.4L engine. They will easily work for an outboard
 

Alumarine

Captain
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Feb 22, 2005
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For my 50hp merc I went to walmart 7 years ago and bought the smallest marine starting battery they had.
It's still working.
 

Outsider

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Apr 24, 2007
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I've never heard anyone complain about a battery that's too big. Considering the likely charge capability of your 1792 motor (anemic), I know what direction I'd go ...:wink:
 

NYBo

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Oct 23, 2008
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I've never heard anyone complain about a battery that's too big.
How about the guy who has to haul one throught the woods to and from the water on an electric-only lake?:faint2:
 

fishin98

Chief Petty Officer
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Nov 28, 2009
Messages
521
I ran a Grp 24 Walmart battery as the starting battery for the 90Hp Merc on my Bayliner Capri. Then I used a Grp 29 Walmart for my AUX/Trolling motor. The Grp 24 lasted 6 years, The Grp 29 lasted 5 years. Used a ACR to keep the Grp 29 topped off when running the motor. Hard to beat the Walmart Batteries.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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My 1792 Johnson 65 hp model 65esl72s previously had a 660cca battery attached. The battery has failed. It made it 15 years so I can't say I'm mad BUT that's a bigger battery than my SUV has. So just how big of a battery do I need? I boat during the summer, no breaking ice to get a worm wet on my boat.

if your battery dies in your truck because you left the radio on, you walk home. if your battery dies in your boat because you left the radio on, you swim home pulling a boat.

to crank your 75hp johnson, you may get away with a lawn tractor battery. however if you do a lot of starting and stopping with minimal running in between, you will want the higher reserve capacity.

I suggest a group 27, only slightly larger than the group 24 and more reserve capacity. I also look for 600+ CCA.
 
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