Help selecting a trolling motor/battery?

[TheDL]

I've had the luxury of riding along in others' boats for a while now - but I've got a 14' aluminum boat now, with a 15HP motor and I need to pickup a trolling motor and battery.  I don't know much, so I'm looking for some advice.  The local shop has a pretty weak selection - but I'm looking at a 12V 30-40lb thrust minkota endura (transom mount).  I'm kind of lost on the battery choice too - never heard of the "nautilus" line of batteries they have for sale.

What should I look for in the motor or battery feature wise.  What is a group size on the battery, it seems higher number is more expensive...and what is a spiral grid battery    Is there a benefit to a "starting and deep cyclce" vs. just a "deep cycle"?
Will one battery be good for a whole day of fishing?
I'm not seeing the infinitely variable speed settings untill I jump up to the $600 price mark - is there really that much advantage over a 5-speed forward, 3 reverse? How do I know if I need a 30 or 36" shaft?

Any help would be much appreciated.

[bigredfishing]

Well how often are you looking to fish?  How hard of winds do you fish in?   Will you be trolling with the motor?

bow mount or stern mount?

This is what I can tell you

Cheaper batteries usually have fewer "cycles" before they lose their ability to hold a full charge, but if your only fishing 10-15 times a year at 6 hours or less a day, one basic group 27 12v deep cycle should be fine.

I have a 55# thrust 12v minn kota and I can troll 6-10 hours on one group 27 12V optima (spiral cell) with my 12' rowboat

i have an 80# bow mount 24V on my Lund with 2 group 27 AGM batteries that runs for about 25 hours before it starts to slow down.

here's some links to check out

http://www.bassdozer.com/articles/crawford/trolling_motor.shtml

http://www.basspro.com/webapp/wcs/stores/servlet/CFPageC?storeId=10151&catalogId=10001&langId=-1&mode=article&objectID=32826

[TheDL]

BigRed - thanks for the info - to answer your questions:

I will be fishing in it 1-3 times per week, for anywhere from 3-9hours per trip.  Usually winds below 15km/hr, averaging 0-8km/hr (smaller lakes, some windy days).  Yes, trolling with the motor sometimes....more often using it to hold position or work an area with main motor trips in between. 
Stern/transom mount
What is a AGM battery?  So the # before "group" (i.e. 27 group, 34 group) indicates what?

Thanks for the help!

[TheDL]

What is a AGM battery?  So the # before "group" (i.e. 27 group, 34 group) indicates what?

I should've opened the link first....I'm reading it now.  Thanks! 

[Terasec]

Something to consider
If te battery is staying in the boat, might be worth getting the highest amp battery you could afford,
If you will be lugging the battery to and from the boat, weight might be an issue.
A trolling motor generally draws its thrust in amps per hour.
So a 40# thrust trolling motor will draw about 40 amps per hour at full thrust.

[TheDL]

Thanks Terasec - never even though of that...yes, the battery will be coming out of the boat when not in use...good info on amps/hour too!

[greensider]

ive had an optima for 7 years it last all day and is still as strong as when i bought it ive used alot of other ones in the past but ill never buy anythinh else but an optima again yes theyre expensive but well worth the mony

[montanaguy]

It will depend totally upon how much you use it and how much you troll. Out here in Montana, we troll lots for trout and walleye, and yes, the speed is very important. My wife and I will be hauling them in when others are not catching anything, and they haven't figured out it's the speed as they go sailing by us. Nothing is more frustrating than running out of battery when the bite is on, and the wind can sure eat up a battery. Don't think you can have too much battery. We have a 70# thrust with a 24 volt system on a 20' jet, and can use them up in 8-9 hours if we're fighting the wind.

[TheDL]

Hey - great advice guys!  Well, turns out I lucked into a "free" trolling motor/battery/charger!  I was discussing this with my new neighbour and he said I got one sitting in the box you can use!  I managed to score (temporarily) a 12 v. 55lb thrust transom mount min kota, with a 2 deep cycle marine batteries (gel cell) and a nice multi-stage charger - all in exchange for a few fishing trips and a hand around the fields!  SCORE!  I should have it all setup by next weekend!