You'll need the 80lb otherwise you're guaranteed to be disappointed on run time, power, and capacity. I have a similar 20' with the 80 and I wouldn't go less. I just upgraded to a riptide (did more salt than I initially expected) and went with another 24v rather than 36v.

How long your batteries last is a function of how you're fishing and what the reserve capacity (RC) is of your batteries (mine are 115). If I'm bottom bouncing for walleyes at .8 to 1.3 MPH (I tend to go 1.1 ish) my batteries will last a long weekend. If I'm trolling all day (say start at 4:30 or 5) for salmon in the river while using my kicker for thrust I'll be 80+% discharged by ~16:00 and that deep of a discharge is bad for my battery (but I do it anyways. Different discussion).

So. How do I deal with this issue on long trips?

If I'm staying at an Airbnb or a hotel I make sure to bring a long extension cord.

If I'm camping I bring a generator just to charge the boat.

I have a Minn Kota "alternator" installed which takes the excess amps from the main motor and charges my trolling motor batteries. I love it. I won't have a boat without one. But. It's got limitations and you have to accept them or you'll be deeply disappointed. Some of my salmon spots I might never start my main all day or only run it for 5 minutes in which case it doesn't do anything for me. But. If say I'm fishing for walleye and running back and forth across the lake it will have a measurable impact on my depth of discharge. I like downhill trolling for salmon at the reach which is a 10-20 min downhill troll followed by a 5 minute run up. Before the alternator I would've been done by 16:00 with a (nearly) fully discharged battery now I end at about 17:00 with 20-30% remaining. Set reasonable expectations.

Rather than investing in a second set of batteries you're better off to pay the cash upfront for a nice set of batteries. There's a lot of current and past threads on this topic. I use two D31 AGMs @ 70+ lbs each while others use lithium. Personal choice. Jeb is pretty knowledgeable on the lithium stuff.

What else could you do? You could go with a 36v system which would last longer. But. It's much more expensive and you'd seriously want to consider lithium to reduce weight which would result in a huge increase in cost.

I'm addicted to my bow mount and I can't imagine not having one. I fish 100+ days a year and 90% of the time I'm solo. Life just wouldn't be enjoyable without one

 

You didn't say how you intend to use the motor? Is it for steering while your kicker pushes the boat? You doing bass fishing or spotlock fishing? Or do you expect this motor to pull you down the Columbia running protrolls and spinners?

Minn Kota makes a 70lb motor at 24V. I'm guessing you will want at least a 80lb motor. Next size up is 110lb 36V motor.

I run a 80lb Riptide Terrova on my 18 footer. It's enough power to run protrolls on the Columiba for longer than I care to fish. They are great motors. Too much power is better than not enough. Too much shaft is better than not enough. Look at the Kipawa props for extra power.

Also you are going to get lots of opinions on batteries. My advice is to go go cheap on the first set while you are figuring things out. When those batteries die in a few years then splurge on lithium ions or whatever you want. Bimart has their deep cycle batteries on sale right now. They were on sale in May last year for $80 so they might go on sale again in May. I run two of these in series for 5 hours of trolling time. I haven't tried trolling longer than that. I got 1 season out of them so far.

Sent from my SM-G781U using Tapatalk

 

Been there done that. I had a 55 on a 20 foot stryker for a couple years. It worked. It just wasn’t optimal. Then I ran to 12 V batteries in parallel. It worked better longer, but still under powered. Especially if you’re trolling for salmon on the Columbia River. You’ll definitely need a kicker for proportion. I just upgraded to a 80* 60”. That would be min. Through my experience

 

I’ve got an older 20’ open Jetcraft that has very similar lines to a Scout. It’s a wide hill with a 6 degree or so bottom that gets pushed around by the wind badly when trolling or drifting. Putting an 80 pound 60” Riptide Ulterra on the bow was an absolute game changer. I can fish with one hand on the tiller which is something I just couldn’t do on even slightly breezy days. I went with the Ulterra because 1) I found a great deal on a used one during Covid, 2) I watched a friend snap a very expensive fly rod trying to rush to the bow to deploy his Terrova and I know that I am every bit as clumsy, 3) my fair skinnned Irish/Finnish wife likes to keep the bimini portion of my fisherman’s top up pretty much all day/every day out on the water and it’s pretty low for me to get under it to get a Terrova deployed and stowed over and over without smashing rods and stumbling into stitches.

The downside of the Ulterra is some reliability concerns with earlier versions and it seems like folks that run them with oversized skegs have trouble after awhile. Mines been problem free but I’m knocking wood while I type that. You also can’t deploy an Ulterra with the Minn Kota phone app (you can do everything but deploy/retrieve) so it’s a hood ornament if you leave your remote on the charger at home the first time you’re going to use it like an idiot. Yep, that’s me. A Terrova functions normally with the phone app. If you have an Ulterra iPilot Link and a compatible Humminbird fish finder (Helix GN2, GN3, GN4, and higher end models) connected to your Minn Kota you can completely control and program the unit from the fish finder if your remote is sitting on your desk under your truck keys so you won’t forget it.

I decided to bite the bullet and went with a 100 ah 24v LiFeP04 battery from Enduro Power in Colorado. Seems like a good company and their customer service is based in Colorado. I had lots of conversations with other manufacturers and having US based support is a nice feature. I have 1 larger battery (still much smaller than 2 group 27s) that can be mounted in any configuration and it weighs 43 pounds. That saved me more than 100 pounds of battery on my bow. I have it mounted in my bow anchor locker and still have room to store an anchor/rope if I decided to bring one. I usually just carry a small emergency anchor with a 50’ rope because the spot lock works so well. I can run the battery down to just about zero without damaging it and it keeps its power output near 100% until it’s discharged. It can handle about 3-5 times as many cycles as wet cell or AGMs so it should last a lot longer and be less expensive per cycle. I plan on keeping this set up for a long time so it made sense to buy once, cry once.

 

As already stated...it depends a lot on your use case.
If you are using it mostly as a rudder and pushing with a gas kicker in the back, you can get away with less. But if you are using spot lock, trolling in windy conditions, etc...then you will be disappointed.

When pushing the motor to the higher thrust setting under the latter conditions, you have to remember that your current draw (amperage) goes up and the efficiency goes down. This is the laws of physics (specifically ohms law). As the current goes up, you have higher loss that is just given up by heat. That is why if you look at the wiring & breaker charts for the motors, the wire size & breaker requirements are less when you make the jump from 12v to 24v (specifically from 55# to the 70#).

 

Jeb, I've seen that chart from MK before, at least in regards to the max amp draw, but I haven't seen a plot showing amps versus throttle setting. Do you know if this it is a linear line, or some exponential curve? That info would help understand available trolling time for a given set of batteries.

 

Officially, Minn Kota does NOT provide this data, only Max power draw.

https://minnkota-help.johnsonoutdoors.com/hc/en-us/articles/5975498407319-Trolling-Motor-Amp-Draw-

Some folks have tried to chart this...but honestly, its not accurate - its just a guestimate.

Calculating Motor Run Time

A common question people have when trying to select a motor is “How long will this motor run out on the water?” To answer this question, it's necessary to know two things: a battery's amperage hour rating and a motor's amperage draw. Keep in mind that trolling motor run-time is not an exact...

www.trollingmotors.net

Edited...added chart from Garmin:

Force Trolling Motor Owner's Manual - Motor Thrust and Current-Draw Information

www8.garmin.com

Even the Garmin chart, lists a caveat...this measurement is only in calm water...once you change the environment, your power draw goes up. Therefore, these numbers are not really 'real world' accurate...they are just a guestimate too.

Why is it not accurate? Because there are a lot of variables, such as current, wind, temperature, etc.etc. It all factors in the actual power draw. Oh...and as your lead acid battery discharges, the voltage drops, and then guess what, the amperage goes up. (Watts law goes into affect here...power stays constant...voltage goes down....amperage goes up to maintain the same power).

Additionally, the motor controller uses Pulse Width Modulation (PWM) to control motor speed (i.e. it is not a steady voltage/current applied its variable).

I've said this before in the tech forum and I'll say it again. Unless you use a Shunt inline with your battery, you really have no idea what your power draw is, nor your battery depth of discharge.
Google "Victron smartshunt" as an example.

Without a shunt, you are just guessing. Its like having a fish finder without a transducer...you may think there are fish there, or its so many feet deep...but that is a guess without a transducer

 

Just to re-iterate Jeb's comment about the Victron Smartshunt: that is definitely the way to get reasonably accurate information about the true capacity of your battery. It has a spiffy bluetooth interface that lets you see exactly what is going on with your battery and loads from the convenience of your phone. It accurately measures the current draw over time and allows you to account for the Peukert effect for your particular battery (when you draw a battery down quickly, it does not even come class to meeting its amp-hour rating: that is the Peukert effect). With that bluetooth readout on your phone, you will be able to see exactly how many amps your Minnkota draws at any throttle setting - so you can get a good handle on what works and what doesn't for your particular setup. Having a shunt is only half the story: you also need the software and a way to read what is going on and the Victron Smartshunt does all that for you using your phone.

Victron also sells DC-to-DC converters that are a great way to recharge your trolling motor batteries from your main motor while you are underway. They will convert the 12V from your engine alternator to 24V to charge your trolling batteries. If you decide to go with LifePO4 batteries for your trolling motor (cheaper in the long run since they last so long vs lead-acid), the Victron DC-to-DC charger supports LifePO4 and lead-acid charging profiles. They also sell a 12V/12V DC-DC model that is a superior method to charge your house battery from your main motor.

 

I’ve had a 55 lb Terrova and an 80 lb Ulterra on my 21’ Tracker Tundra. I’d recommend the 80 lb. I got by okay with 55 lb but the 80 is just way better in wind and current. If you get 55lb you’ll want to carry a second battery anyway so you’re really not saving any weight.

 

I have a New Minn Kota dual bank charger and two heavy duty batteries (also new) for sale, if you go down that path.

clackamas co boat parts - by owner - craigslist

clackamas co boat parts - by owner - craigslist

portland.craigslist.org

 

I have a lighter weight aluminum 19 footer. It came with a 55lb thrust and that worked great on lakes, but marginal on the Columbia. I installed two group 31 100Ah AGM's and that was fine for a little while, but realized that it was marginal. I upgraded to an 80lb thrust about 4 years ago which made it way better on rivers, but I really got tired of replacing the batteries. Even well cared for I rarely got more that three strong years out of the AGM's, and they were $200 and 80lb a piece. Two years ago I swapped out my onboard charger for a lithium Ion model and installed two 30lb 100AH LifePo4 batteries. All I can say is the difference in run time is phenominal. I also do not expect to have to replace these for another 5-6 years. I actually dont remember the last time I used my kicker to troll or my anchor to anchor.

 

I’ve got an 80 on my 18’ Raider and love it, don’t think I would have the same love for a 55, just my $.02 worth.

 

I have a Minn Kota Riptide Terrova 80lb Thrust 70" shaft powered by two 12V Costco AGM batteries on my Hewescraft Sportsman 180. I have used them for a year (approx 10 trips). So far they are holding up. Most days I can get approx 6-8hrs of power. But on windy days or when I fish in rapid current, then I get approx 4-5hrs. Been thinking about upgrading to either one 24V 100Ah LiFePO4 or two 12V 100Ah LifePO4 batteries. I installed a NOCO Genius Genpro10x 4-bank charger that can charge either lead, AGM or lithium batteries so I am set on the charger. However, deciding which brand of LiFePO4 to use gives me a headache

 

I have a Minn Kota Riptide Terrova 80lb Thrust 70" shaft powered by two 12V Costco AGM batteries on my Hewescraft Sportsman 180. I have used them for a year (approx 10 trips). So far they are holding up. Most days I can get approx 6-8hrs of power. But on windy days or when I fish in rapid current, then I get approx 4-5hrs. Been thinking about upgrading to either one 24V 100Ah LiFePO4 or two 12V 100Ah LifePO4 batteries. I installed a NOCO Genius Genpro10x 4-bank charge that can charger either lead, AGM or lithium batteries so I am set on the charger. However, deciding which brand of LiFePO4 to use gives me a headache

Hi there. May I suggest if you want to talk LFP batteries, perhaps we can work on the long thread going on in the Tech forum.
Trying to keep a single thread that has battery reviews, charger reviews, etc. Otherwise we have like 20 different threads all over the place

Lithium batteries suggestions

I am in need of advice / experiences from those who have purchased lithium batteries for their boats. My fiend has Battle Born brand and is happy with their performance - but admits this brand is pricey. So I researched lithium batteries on web and in reading the articles from various boating...

www.ifish.net

Your LiFePo4 battery options (for marine use) are getting better each week. Seems like everyone is jumping on the LFP bandwagon.
Battery 'type' & chargers are a whole separate discussion...


For the OP, the moral of the story is, go with a larger than expected bow mount. If you undersize, you'll regret it. Most of the tournament fisherman that run bow mounts all day long have found that the sweet spot is about 30% power. That seems to be where the motor runs the most efficient. If you go with a smaller motor, then its is running at higher speed and you'll loose efficiency and your runtime goes down the toilet.

There are just too many variables to try to even recommend stepping down. Stepping up to the next size is going to be a better experience especially if you plan on fishing in various conditions (i.e. not on just the perfect flat lake days with no wind, no current, etc).

-J

 

I've seen several 6-8 hours on the batteries posts. Are you only using the Minn Kota to power your boat? I'll be running a 80# 60" Riptide my 19' Stryker, plan on using the kicker to push the boat and Minn Kota to mostly steer. Went with Bi-Mart deep cycle to get me started.

 

It totally depends on conditions, how you're fishing, the size of your battery, the boat you're using, etc. This isn't a one size fits all answer.

Trolling for walleye with bottom walkers I can get a long (three day weekend) out of my batteries going at a speed of .8-1.3 MPH. Add in wind. It can plummet quickly.

Trolling for kokanee on downriggers at 1.5 I'm in that 8 ish hour category. Why? The drag from two cables 100'+ deep. Turn on the kicker and I don't have a problem trolling for days.

Add in a couple of average weight American males? You're going to draw those batteries down a lot quicker!

Yes. Using your kicker will reduce the power you need to move. However, you need enough speed to steer (even with a skeg albeit less) and to adjust speed. So you'll still have battery draw.

 

Thanks for the link Jeb. Will do.

 

I was always told get more than you think you need. Bigger motor running at lower power will drain a Battey less. Mase since to me. a 112 running at 1/4 power uses less juice then a 55 running 100 percent. So if you want a single battery setup get the biggest you can even if you don't use all 55lbs of thrust if you ever do need it then its there. I went with a 36v system and 112lb even if I never use all 112lbs of thrust I have it if need be plus since its mostly for steering while the kicker does the work I should be able to make the 100ah batteries last a while

 

I had a 55 ft/lb on a 20’ northwest jet. It’s a heavier deeper hull than a scout. It was adequate with kicker propulsion. I liked that it was 12v so my kicker could charge on the battery all the time (Honda kicker, Yami’s wont do it) and I rigged it to plug into the trailer so I could charge the battery with the pickup while traveling. Never had to shore charge or plug it in at home. Was a nice setup.

-Scott

 

My kicker is a Yami. Why won't they work?

 

Thanks for all of the replies.

My primary purpose for the motor would be to fish shorelines. Secondarily, I figured I would use it for trolling, especially in lakes for trout and kokanee. I didn't think about running the kicker and the electric... I suppose you just put the kicker into gear and then do the rest with the electric? Seems like in some situations that might push you too fast? If I had the "alternator" I assume that could be setup to charge from the kicker? That would be handy for steering. I don't plan on fishing the Columbia much, but I do plan on fishing some coastal estuaries.

 

My Bf8 would charge 8 amps at trolling rpm. My new t9.9 charges about 2 amps at trolling rpm and after trolling for 6 hrs running two sonar units and an autopilot my batteries are dead.

 

Sounds like everyone covered thrust, but length is a while nuther issue. Coastal estuaries and sounds like you might be in larger chop than an average lake so make sure you have the length to keep the prop in the water when waves hit. One round of hearing huuuummmmmmmm Thwack Thwack Thwack huuuuuummmmm will make you cry. 😢