What battery to use?

Hi,
I have a question. I recently bought a kayak. I am thinking about rigging a trolling motor on it for fishing. I have a 30 lbs trust trolling motor (minn kota) and I am try to get a battery for it. The marine battery I have for my boat is why too big for me to put on a kayak. My question is that, I general fish for about 5 hours, so what is the smallest battery I can use for this trolling motor? Thanks

Re: What battery to use?

birdgod said:

Hi,
I have a question. I recently bought a kayak. I am thinking about rigging a trolling motor on it for fishing. I have a 30 lbs trust trolling motor (minn kota) and I am try to get a battery for it. The marine battery I have for my boat is why too big for me to put on a kayak. My question is that, I general fish for about 5 hours, so what is the smallest battery I can use for this trolling motor? Thanks

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Unless you have a BIGKayak. A 30 Lb thrust trolling motor is too big also. It will push a Kayak like a jet engine.

Re: What battery to use?

A 30# trolling motor will draw about 30 amps on its fastest setting. Lower settings simply bleed off current in the form of heat so running at slower speeds does not significantly alter run time. If you are on the water five hours you will need a group 24 size deep cycle as an absolute minimum. It's the same size as a small car starting battery. Sorry -- there is no free lunch here.

Re: What battery to use?

cbavier said:

Unless you have a BIGKayak. A 30 Lb thrust trolling motor is too big also. It will push a Kayak like a jet engine.

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What is the right size of motor should i get?

Re: What battery to use?

birdgod said:

What is the right size of motor should i get?

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birdgod, What size of Kayak do you have? I would say a 17-20 Lb thrust should be plenty of thrust, even on a two person Kayak.The battery size and weight are going to be the same but the smaller trolling motor will weigh less.
I used a 17 Lb on a 12 Ft Aluminum fishing boat and it pushed it fairly well.

Re: What battery to use?

cbavier said:

birdgod, What size of Kayak do you have? I would say a 17-20 Lb thrust should be plenty of thrust, even on a two person Kayak.The battery size and weight are going to be the same but the smaller trolling motor will weigh less.
I used a 17 Lb on a 12 Ft Aluminum fishing boat and it pushed it fairly well.

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I have the Hobie quest fishing, weighting about 50 lbs. can you give me a brand to look at, it seem like the smallest i found is 30lbs

Re: What battery to use?

Seems that 30Lb is as small as they make nowdays. You may have to, try to find a used one on Ebay, Craigs List or at a local used motor dealer/ repair center, or just use the one you already have. Remember just because you have the power doesn't mean you have to run it wide open. Auto Zone seems to have the best bang for your buck and warranty on their Deep Cycle batteries. The motor I had was a Minn Kota and it's still running strong after 15 years of use. A friend of mine has it now.

Re: What battery to use?

cbavier said:

Seems that 30Lb is as small as they make nowdays. You may have to, try to find a used one on Ebay, Craigs List or at a local used motor dealer/ repair center, or just use the one you already have. Remember just because you have the power doesn't mean you have to run it wide open. Auto Zone seems to have the best bang for your buck and warranty on their Deep Cycle batteries. The motor I had was a Minn Kota and it's still running strong after 15 years of use. A friend of mine has it now.

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thanks for the info. will give it a try.

Re: What battery to use?

To calculate appoximate run time for a 30 amp motor is as follows. A 120 amp battery. Take the amp rating on the battery and multiply that by .85. Then divide that by the amp draw of your motor on HIGH (which in this case would be 30) and you will get 34000 or 3.4 hours of run time on high if that is what your amp rating is for that motor .This works in calculating all trolling motors. Some of the new units run cooler and will give more use out of a properly charged battery. You can find smaller batteries to keep the weight down but they are expensive. In most cases the slower the speed the less amp draw. If you run on speed one you draw about 17 amps a little over half of the high setting. A 85 -100 amp battery (if used properly) I mean not running on high all the time, should last 5-7 hours on a fishing trip based on the info you have given. Good fishin and keep the dry side up^