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Muskie Fishing -> Muskie Boats and Motors -> Trolling motor Voltage and Thurst
 
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Message Subject: Trolling motor Voltage and Thurst
Musky Punch
Posted 1/15/2009 8:57 PM (#355275)
Subject: Trolling motor Voltage and Thurst


Hey everyone, great forum here and lots of awesome information provided by good people and anglers...

Got a boat and I now have a few questions on trolling motors...

The boat's dry weight is around 600 lbs and its a little over 16 feet. There's going to be a 20 HP motor on it and usually 3 fisherman in the boat avg weight 170-180 lbs. The max capacity on the boat is 1118 lbs to give you guys an idea.

After reading online I know for sure I need at least a 40 lb thrust, most likely getting a 55#.

My main question is on the volt system and how it actually works. I can get a MinnKota endura with 55# thrust transom mount (want transom mount rather than bow) from Gander for $250 bucks. It's a 12 Volt system though and I'm wondering how long that will actually last. Some lakes I fish are restricted to only electric motors and we'll fish basically the entire day. Since I'm relying on specifically the trolling motor to get us around, I don't know if the 12 V will do that. Also, if I go for the 24 volt system.. how exactly does it work? I know it goes off two batteries but is one recharging while the other works or what? How much more is it and is it worth it?

Basically, any information or suggestions regarding the stuff I said above would be great use to me and my family...

Thanks everyone
Guest
Posted 1/15/2009 9:06 PM (#355278 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


Get a 24 volt 65 pound thrust
TJ DeVoe
Posted 1/15/2009 9:15 PM (#355282 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst




Posts: 2323


Location: Stevens Point, WI
A 12 volt system will work just fine. I ran a 30lb. model for years on boat of that size and weight and fished all day with a fully charged 31 series battery. Your boat is very light and won't take much effort to move. I think a 24 volt system would be total overkill in my opinion.
Slamr
Posted 1/15/2009 9:55 PM (#355293 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 7037


Location: Northwest Chicago Burbs
I really won't speak to the specifics of wiring/charging/etc. but I will say this: if you can afford to go w/the 24v system, and it wont crowd your boat DO IT! Overkill is a great thing when the wind goes bad, or you forget to charge your batteries, or you just want to get a few more hours of casting in.
welldriller
Posted 1/16/2009 1:06 AM (#355317 - in reply to #355293)
Subject: RE: Trolling motor Voltage and Thurst




Posts: 402


Location: Eagle River, WI
You can never have to much trolling motor or to much batteries. You can always turn a trolling motor down but its pretty hard to turn a dead battery up.

A 24v system works by wiring 2 batteries in serial. You have to tie the positive on one battery to the negative on the other battery and then you will have one positve and one negative left between the two batteries. Those two lead will give you 24v.
TJ DeVoe
Posted 1/16/2009 1:38 AM (#355320 - in reply to #355317)
Subject: Re: Trolling motor Voltage and Thurst




Posts: 2323


Location: Stevens Point, WI
Let's think about this for a second. He's got a boat that weighs around 600lbs., gonna have three guys around 170-180 but the boat has a capacity of 1118lbs. Let's do the math here.

Three guys at 175lbs=525lbs.
A new 20hp Mercury=115lbs.
One Optima D34M battery=60lbs.
Tackle, beer, gas, anchors and anything else=200lbs.

A grand total of about 1500lbs. There are heavier boats out there that with a 12volt system and with a good battery run all day no problem. A 24 volt system is waaaaaaaaaaay overkill for his rig. Get yourself a good battery like a Trojan or Optima, and it'll last you all day no problem. I know an Optima will, I've beat the crap out of a couple and there still going. I've actually gone for multiple days without charging. I'd suggest, try a 12 volt system first, if it doesn't last for some reason, which it will, add a battery.

I personally ran the same rig for many years when I was a teenager and younger, had no problems at all. Fished 5-6 days a week and didn't charge the battery as regularly as we should have without any problems. Charge your battery after each use, and you'll be fine. Get an Optima, it'll last two days without a charge.



Edited by TJ DeVoe 1/16/2009 1:40 AM
4amuskie
Posted 1/16/2009 7:30 AM (#355330 - in reply to #355320)
Subject: Re: Trolling motor Voltage and Thurst




I say stay with the 12 volt. If its not enough you can always get another battery and link it with the other. That way you will have two batteries if needed.
Halfpint
Posted 1/16/2009 8:09 AM (#355337 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


If you're going to fish a trolling motor only lake, you need to be prepared for everything. You want to have all options available to you...you don't want to be restricted from fishing the wind blown side of the lake for example. I think you should either go with the 24 volt system, or buy a crap load of batteries and swap them out.

I have a 14 foot sea nymph, just me and my brother fishing, and our gear. We have a bow mount 40lb powerdrive, and when we're at the trolling motor only lake we like to fish, we strap on a 55 lb transom mount. It's a light boat. The trolling motors get us around fine. BUT, it does take juice getting across the lake. And, if there's wind, it takes quite a bit of juice. We also like to troll some in this particular lake, which will send you home quickly or strand you on the opposite side of the lake. A few times we've been ducking down to reduce wind drag, running both motors at once, and barely making it to the other side of this 200 acre lake.

We started out with two batteries. Needless to say, that didn't work. I think wind actually begins at this lake we go to. So after those first two batteries died one day, I drove to wal-mart and bought another one and went back to the lake...just to get more time in. Now I'm up to five batteries...we keep the extras in the truck and swap them out throughout the day. We do pretty well now, but if I could go back, I'd have a 24 volt high thrust motor. I would still have 4 batteries (one less), and I'd run the hell out of them, and just have the extras to swap out in case.

Some things to consider as well. Small light boats blow around like hell. If I'm not on the motor, I'm across the lake pretty fast. So you'll USE your motor a lot more. Also, transom mounts are less efficient. If you use a transom mount, prepare to use more batteries.

Best bet is to be prepared and go big. Especially on a trolling motor only lake in a small boat.
gopackgo
Posted 1/16/2009 8:16 AM (#355339 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 386


I had a much heavier 16' boat, had a 55# thrust, 12v and was able to run it ALL DAY without it ever going lower than half charge. Yeah, overkill is good, and if you can afford it, go 24v, but if you're on a budget, you will have no problems with a 12v.
Halfpint
Posted 1/16/2009 8:24 AM (#355340 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


I suppose it does matter what type of lake you're fishing too....

We fish a 200 acre lake with grasslands surrounding it. It gets windy and there aren't many wind breaks...even the non-windblown side is windy. If you are fishing a smaller lake with hills or woods around to provide protection, then you might make it all day.

If you go 12 volts though, just take extra batteries.
Shep
Posted 1/16/2009 4:04 PM (#355453 - in reply to #355340)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 5874


I ran a 12V 30 lb TM on my old Rampage for years. Always had enough juice left in the battery at the end of the day. Why? Because I ran two batteries in PARALLEL. You nearly triple your run time this way, providing the batteries are fully charged when you start out.

To answer some of your questions.

In a 24V TM, you use both batteries, wired in series. 12V + 12V = 24V. They are both being drawn at that rate. At full power a 24V TM will draw 1/2 half the current of a 12V TM of the same thrust. Thus the batteries last longer. Also, you are able to build motors with more thrust for a given current. That's why you can get 80 lb motors in 24 V, but are limited to about 55 lbs at 12 V.

If you want to extend the run time of that 12 V TM, add another battery and connect to the first in parallel. That mean adding a jumper form neg to neg, and pos to pos. As I said, this will nearly triple your run time. There are several post with good drawings in this forum. EsoxManiac, AKA Al , does a nice job with the drawings to explain parallel or series connections.

My advice is that a 55 lb 12V is plenty of thrust, and after running this setup for a while, if you find you need more runtime, add another battery in parallel.
Shep
Posted 1/16/2009 4:07 PM (#355454 - in reply to #355337)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 5874


Halfpint - 1/16/2009 8:09 AM

I think wind actually begins at this lake we go to.


Waves make the wind blow. Right, Riddler?

halfpint. Take a second battery, and connect it in parallel. You'll be surprised at the additional runtime you get.
mseybert
Posted 1/16/2009 6:17 PM (#355484 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 443


Location: Indiana
I found some calculations online that give an estimate of runtime for trolling motors at a given setting. This is probably not a hard fast calculation, but a reasonable estimate.

For Example: A 55 pound 12V trolling motor is likely to draw 1.2 amps per hour at 100%. Say you have a battery with 100 amp hour rating you might expect to get:
7.5 hours at 20% power
3.8 hours at 40% power
2.5 hours at 60% power
1.9 hours at 80% power
1.5 hours at 100% power

I found it interesting and probably just a good guesstimate.
lambeau
Posted 1/17/2009 9:42 AM (#355576 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst


i've always been a big fan of the "you can never have too much power" approach. imho, it's ALWAYS a good idea to max out your power sources: trolling motors, main motors, etc. i feel that "it'll do" works in many/most situations but will leave you frustrated and ticked off on those occasions when you could use the extra power or runtime.

my personal experiences are that running the trolling motor at a lower power setting has meant that i get more runtime. it's pretty self-evident and i'm sure most everyone else knows this...the faster you run the more juice you use. Mike Seybert provided some data he found that shows just how dramatic the difference will be between low and full power. because of that i prefer to max out on power and run it at a lower setting.

it's something to consider for your boat when buying a trolling motor:
- the 12v with one battery will push it around just fine, yes.
- a 12v with two batteries in parallel will push it around just fine and have longer runtime.
- a 24v will push it around fine at lower power giving you longer runtime.
- a 24v will have much more power available for those "just in case" situations.
jonnysled
Posted 1/17/2009 9:47 AM (#355577 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 13688


Location: minocqua, wi.
great information from mseybert ...

consider now that under most conditions you'll run an average of 40% ... and the more you draw the more you slide the slide up throughout the day til the trolling motor ends your fishing.

on that setup the trolling motor "could" determine the end of your day. best thing to do would be to change that scenario and go overboard so that won't happen.
knooter
Posted 1/17/2009 10:15 PM (#355697 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst




Posts: 531


Location: Hugo, MN
That isn't a very big boat he's talking about, and it's certainly not a boat that is going to be battling four footers any time soon. If you encounter four footers in a small aluminum boat, I'd worry more about a properly rated life jacket. A 55 lb 12volt would be more than enough. I ran a MinnKota 50# 12v on my 17' Lund Mr. Pike for five years, and the only time I had an issue with not having enough power was in heavy current (like 3 mph current near a bridge). My boat is much heavier than the boat in question. I ran two batteries in parallel, and never ran out of juice even in a fifteen hour marathon day. I have since upgraded to an 80# 24V system, but I think I could get by with even 70#.
I've seen firsthand a trolling motor that was oversized for a boat. You typically run somewhere between 2 and 4 out of 10 on the minnkota footpedal. If the motor is oversized you'll have to run it between 1 and 2, which doesn't give you much room for fine tuning. It will always seem like you're going too fast or too slow. With the transom mount unit especially, it's a hassle to be constantly changing speeds. With a small margin of error, you'll find yourself occasionally overaccelerating and knocking your fishing partners off balance.
I'd recommend sticking with the 55#, 12v with two batteries run in parallel. You'll not be disappointed.
TJ DeVoe
Posted 1/17/2009 10:23 PM (#355698 - in reply to #355697)
Subject: Re: Trolling motor Voltage and Thurst




Posts: 2323


Location: Stevens Point, WI
Overkill is one thing on larger boats, but overkill on this rig is just that, overkill and money not well spent. Just like majority have said, get the 12 volt, start with one battery, you can always add a second and parallel them. Your looking at probably an extra $150-200 for a 24 volt system.
sworrall
Posted 1/17/2009 11:29 PM (#355713 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 32880


Location: Rhinelander, Wisconsin
I ran a 17' fiberglass boat last year with a 40 HP Merc as my 'small lake' rig. I chose a 55# 12 volt MotorGuide Wireless bow mount, and was able to fish two days, no matter the conditions, before losing the battery. I used to have it hooked up parallel, like Shep suggests, but lost the number two battery to a bad cell a year ago and didn't replace it yet.

If you go 24 volt, get the Marinco system so you can charge easily through the plug and use the system to power 12 volt if you wish.
Almost-B-Good
Posted 1/18/2009 6:11 AM (#355720 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst




Posts: 433


Location: Cedarburg, Wisconsin
Tough question. The amount of energy you will need can only be determined by trial.

If you get a 24V system, then you will always have to have two batteries on board which is extra weight in a boat already short on horse power for the load. You will need to disconnect the batteries and charge them one at a time, or get a charger with two banks isolated from each other so you could charge them both at one time. Or buy a switch that reconfigures the batteries from series for running to parallel for charging with a 12V charger. Any way, more work and/or more expense. The advantage is that the 24V system is slightly more efficient and will let you move faster too. But if you run it wide open, you total run time may not be any longer than with a 12V setup.

The 12V system needs only a standard charger, but remember to disconnect your trolling motor from the battery when charging. If one battery doesn't have enough reserve to last the entire day, next time add a similar battery in parallel to double your reserve. You can still charge them both at the same time with the same charger, only it will take twice as long as you have twice as much energy to restore.

I'm pretty sure I saw graphs illustrating that the faster you go the quicker your batteries will deplete, so you will actually get more miles running at a slower speed with the same battery. If it were my rig, I'd get the 12V motor and hope one battery was enough. If not, I'd add another in parallel.
ESOX Maniac
Posted 1/18/2009 4:08 PM (#355806 - in reply to #355484)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 2752


Location: Mauston, Wisconsin
mseybert - 1/16/2009 6:17 PM

I found some calculations online that give an estimate of runtime for trolling motors at a given setting. This is probably not a hard fast calculation, but a reasonable estimate.

For Example: A 55 pound 12V trolling motor is likely to draw 1.2 amps per hour at 100%. Say you have a battery with 100 amp hour rating you might expect to get:
7.5 hours at 20% power
3.8 hours at 40% power
2.5 hours at 60% power
1.9 hours at 80% power
1.5 hours at 100% power

I found it interesting and probably just a good guesstimate.


Mike - You are right it is a guesstimate, although a poor one. As Shep said above if you cut the load in half the runtime will be 3X. You get the same effect by adding a second battery. That is definitely a provable engineering fact for lead-acid batteries. The unknown author's chart doesn't fit that fact. f. ex. from 80% to 40% is a 50% cut, yet the author has simply doubled the hours. He really misses the mark at 100% power.


Ampere hours (Ah)
Tested at 77 degrees Fahrenheit. It is the amount of current (in amps) a battery can deliver, multiplied by the amount of hours, without falling below 1.75 volts per cell (10.5 volts on a 12-volt). Most marine/RV-deep cycle batteries are rated on a 20-hour discharge rate. Example: a 100 Ah battery can deliver 5 amps for 20 hours (amps x hours = Ah).

There's also something wrong with his ampere figure of 1.2A

Basic Electricity for Muskie Fisherman 101:

Electrical engineers (like Shep & myself) measure electrical power (real power) in watts.

1 Volt (V) x 1 Ampere (A) = 1 Watt (W)

so given 12V x 1.2A = 14.4W Your body radiates more energy just resting. Does anyone honestly think a 55# TM only draws 1.2A at 100% load? I don't. Actually a quick google search turned up this ->

http://www.buy.com/prod/minn-kota-edge-55-lb-thrust-trolling-motor-...

50 Amps Max draw. That's quite a difference. How long would a 100AH battery last on this motor at different power levels? Well if I look at a Trojan 27-AGM 12V
Deep Cycle Battery it's rated 100AH. It has a marine reserve capacity of 175 minutes at 25A@77F.

100% power (50A) = ~58 minutes
66% power (35A) = ~ 116 minutes (1.93 hrs)
50% power (25A) = ~175 minutes (2.91 hrs) - marine reserve capacity
33% power (15A) = ~ 348 minutes (5.8 hrs)
25% power (12.5A) = ~ 525 minutes (8.75 hrs)
15% power (7.5A) = ~ 1044 minutes (17.4 hrs)
10% power (5A) = ~1200 minutes (20 hrs)

For those whom may be interested - 1 hp = ~746 watts

So the 55lb trolling motor uses ~ 600W at 100% power or ~ .8hp of electrical energy.

Are we having fun yet? I agree with Lambeau- go for the most power you can afford - both in battery and TM capacity. If you don't have it, you can't use it!
Al

Halfpint
Posted 1/19/2009 8:30 AM (#355946 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


Wow....I think the drugs I took in college killed the brain cells capable of understanding that post. LOL!!! Good riddance brain cells...the fun was worth it!

I've thought about running two batteries in parallel, but right now what we have works...and I'd probably mess it up. I know there was a thread a while back about how to configure it...I'll have to search and check it out

Seybert can verify the difficulty of fishing the particular lake I fish. It's large for an electric only lake. It has no surrounding hills or trees. And it just gets windy as anything there. If it's a windy day, most guys with 24 volt motors will not last all day on one charge. A 16 foot boat with a 55lb 12 volt would not last all day on one battery...absolutely no way. Remember...trolling only means you can't use your big motor to get to the other side of the lake. If you want to switch spots, it kills your batteries. And if you want to actually troll for cold weather muskies, you need to overkill or you'll be paddling.

The original poster asked us to consider that he fishes electric only lakes for entire days. If he wants to be prepared for windy days of 15-20mph, for long days, for trolling, for getting to the next spot on the other side of the lake...he should either go with a 24 volt high thrust so he can run lower power and last all day (and zoom to the next spot), or he should go with a 12 volt and take multiple batteries...either ran in parallel or just take a butt load of them.

My two cents...actually, I think that's now four cents.

Peace Buddies!
pgaschulz
Posted 1/19/2009 11:56 AM (#355991 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 561


Location: Monee, Illinois
24 volt you cant lose
mseybert
Posted 1/19/2009 6:07 PM (#356088 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 443


Location: Indiana
Halfpint is the king of that lake. He is not kidding, it is WINDY there even in 10mph winds. He and his brother seems to have it down, I suggest taking his advice because he has experience on electric only lakes. I have obviously fished the lake some too. I can cast with my 24volt motor all day, but I can not do alot of trolling and expect to fish all day. Go for 24volt if you are mainly a caster, or 12 volt and take a bunch of batteries if you intend to do alot of trolling.

Just my opinion.
Halfpint
Posted 1/19/2009 8:09 PM (#356122 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


Thanks for the props Mr. Seybert. Although I think I'm going take the others' advice and hook up my batteries in parallel. The fish will have no chance!!!!!

If I had the bucks for a 24 volt though, that'd be ideal...just to have the extra power to beat the pan fishermen who like to pull up on our spots :0)

pgaschulz
Posted 1/24/2009 12:11 PM (#356967 - in reply to #355275)
Subject: Re: Trolling motor Voltage and Thurst





Posts: 561


Location: Monee, Illinois
I thought that is all you did is fish for pan fish Halfpint lol
csurp
Posted 2/1/2009 10:18 PM (#358639 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


really folks this is a no brainer

if he can afford it and has the space get a 24 volt

the first time he wants to cross a cove or charge into the wind...he wont regret it.

my 24v MK max 80 will pull a triton explorer 2.6 mpg gps or idle down to nothing...both settings get used regularly
Beaver
Posted 2/9/2009 11:50 PM (#359880 - in reply to #358639)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 4266


If he's worried about running time most of all, why not rig up 2 batteries in series? I had 2-115amp batteries rigged parrallel and could run it on 3 day weekends without a charge.
Now I have a 24v system and an on-board charger. Couldn't believe the power increase. I almost knocked myself out of the boat when I wasn't careful about my setting.
cband
Posted 2/10/2009 10:37 AM (#359929 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 100


Location: W-PA
ESOX Maniac, Could you post one of your pics or diagram on how to rig two batteries in Parallel.

Edited by cband 2/10/2009 10:38 AM
guest
Posted 2/12/2009 1:15 PM (#360296 - in reply to #355275)
Subject: RE: Trolling motor Voltage and Thurst


dude,

I've put a 101lb 36volt on a canoe (square stern) for electric only waters. I ran it down trolling big baits in about 4 hours.

You need all the power possible. Go the the max. volts and
ESOX Maniac
Posted 2/13/2009 9:43 PM (#360530 - in reply to #359929)
Subject: RE: Trolling motor Voltage and Thurst





Posts: 2752


Location: Mauston, Wisconsin
Here you go. Be sure to hook the battery jumpers and trolling motor cabling up as shown. It balances the load between the two batteries. If you hook both trolling motor cables to the same battery, one battery will be working harder - trust me!

Have fun!
Al


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