# what type of battery for electric start 25hp merc???



## lowesam (Jul 14, 2010)

do i need a deep cycle marine battery or just a regular car type battery, i have been using the same battery i use for my trolling motor, but the wife ok'd me to buy a battery since all the bills are paid up and we got a few extra bucks. any advice is greatly appreciated. i've never had an electric start motor before so i'm already in heaven.
thanks
sam


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## Whoopbass (Jul 14, 2010)

I use my trolling motor battery as well and it works fine. I would just keep using that unless your motor doesn't have rope start as well. If I was going to buy a battery I would either buy a cheap small car battery or a deep cycle battery that you can also use as a trolling motor battery just in case your trolling motor battery gets ran down in the middle of your trip.


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## po1 (Jul 14, 2010)

Go with a deep cycle marine battery if you can afford it, a auto battery isn't the best choice with the heavy drain and charging you'll put it thru. I've got my Nissan 18hp electric and trolling motor hooked to a deep cycle marine battery. This way I keep the battery topped off while running the Nissan. Nothing finer then hitting that start button on a electric start, I'm glad I went that way to.


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## Whoopbass (Jul 15, 2010)

po1 said:


> Go with a deep cycle marine battery if you can afford it, a auto battery isn't the best choice with the heavy drain and charging you'll put it thru. I've got my Nissan 18hp electric and trolling motor hooked to a deep cycle marine battery. This way I keep the battery topped off while running the Nissan. Nothing finer then hitting that start button on a electric start, I'm glad I went that way to.



By the sound of his post he just wants a battery for the motor and if that's the case then he could get away with a lawn mower battery. Lighter and smaller the better or buy a second marine battery that can double as your trolling motor battery. I wouldn't get a starting/trolling motor battery since you don't need the cranking amps. A straight deep cycle trolling motor battery is fine.


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## crazymanme2 (Jul 15, 2010)

I use a AGM (Absorption Glass Mat)battery (lawn mower size) for my motor.

About AGM batteries

AGM battery technology has continued to develop and offer improvements over other sealed battery technologies. AGM technology has become the next step in the evolution of both starting and deep cycle sealed batteries for marine, RV, and aviation applications. This "next generation" technology delivers increased safety, performance, and service life over all other existing sealed battery types, including gel technology. 

In AGM sealed batteries, the acid is absorbed between the plates and immobilized by a very fine fiberglass mat. No silica gel is necessary. This glass mat absorbs and immobilizes the acid while still keeping the acid available to the plates. This allows a fast reaction between acid and plate material. 

The AGM battery has an extremely low internal electrical resistance. This, combined with faster acid migration, allows the AGM batteries to deliver and absorb higher rates of amperage than other sealed batteries during discharging and charging. In addition, AGM technology batteries can be charged at normal lead-acid regulated charging voltages, therefore, it is not necessary to recalibrate charging systems or purchase special chargers. 


It handles vibration better also.Cheaper than a gel also.I've had mine for 5 years & no problem.Paid I believe $65.


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## waterboy (Jul 20, 2010)

crazymzn, the AGM *lawn mower* size battery sounds like a good idea for just cranking up the big motor. What battery do you have and I wonder if it will work well with an 86' 30hp Evinrude?


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## crazymanme2 (Jul 20, 2010)

I bought the biggest one they had in the small size.It should be no problem cranking your 30 hp.Just make sure you run big enough wire.I run #4 tinned wire.I bought it off e-bay for $1.35 a foot.


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## waterboy (Jul 20, 2010)

Thanks crazyman, when the current cranking battery dies I'll check in to getting the AGM lawnmower battery.


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## zerofivenismo (Jul 21, 2010)

I'd roll with a dual purpose marine battery (starting/deep cycle) that way you can switch your TM on it if your TM battery ever runs low/out of juice.


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## tdub (Jul 21, 2010)

Use a deep cycle battery. They are made to charge , run down and charge again.


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## crazymanme2 (Jul 21, 2010)

You can also charge , run down and charge again the AGM batteries.


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## sturdi87 (Jul 22, 2010)

crazymanme2 said:


> I use a AGM (Absorption Glass Mat)battery (lawn mower size) for my motor.
> 
> About AGM batteries
> 
> ...



I have no idea what that all that means but wow it really sounds good. My trolling motor was accompanied by a manual that said it may cause damage to the trolling motor/and or the other accessories connected to the battery, if the trolling motor battery is also used to crank, power a chart, lights, etc. etc. (other accessories). I bought a 29 series marine for the minn kota edge 45 and a 24 series marine is currently cranking my 40 horse, running nav lights, docking lights/fishing lights, and a lowrance 5x pro. As its so hot out I launched my rig a midnight last night and got home around 10:30 am this morning with all lights and chart running the entire time I was out basically and virtually no dent made in the 24 series cranking/accessory battery. I don't think I paid more than $55 for the 24 series marine at wally world and the 29 I use for trolling was double that. Keep in mind that includes probably an hour of run time for the 40 which charges the 24 series while it runs.


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