What lithium battery for an electric trolling motor 12v? 14ft boat.

[OffGridIdaho]

Does anyone have small lithium packs to make a battery or should I buy a pre-made one?
Need 12v and about 4hrs runtime with a 40lb motor. The boat is a small 14ft mirrorcraft.

 

[sunshine_eggo]

Issue with motors is surge, which can be 5X the run current of the motor. You'll need to get the specs on the motor, figure your four hour runtime current (1/4, 1/2, full?), determine your Ah required and then find one that can handle 5X the peak motor current.

 

[Whinny]

Have you used this motor/ boat combo on lead acid? If so what ah battery and how long did it last?
My guess would be 200ah and would suggest prebuilt. I run a 50ah battery on a 30lb motor 12 foot, have no issues with surge. Run time is unknown-solar panel is almost always connected. Solar supplies 90% of power at trolling speed during the day.

 

[Luk88]

I would suggest prebuilt too, you'll appreciate sealed case etc. The problem is there are so many scams with small prebuilt batteries you need to buy it where you know for sure you'll have free return (amazon, Aliexpress in the EU with CC). Also without at least a clamp on multimeter that can measure DC current you can't really tell if you got scammed. If you're not sure you can verify a battery's parameters I'd stick to some local brand with good reviews and warranty (and pay 50% on top for the peace of mind).

 

[Checkthisout]

Does anyone have small lithium packs to make a battery or should I buy a pre-made one?
Need 12v and about 4hrs runtime with a 40lb motor.

Just your typical ampere time.

Yes they make cases for diy but probably not worth it once you buy that and bms.

Totally worth it if you already have the cells or can sneak them into an order of larger cells and you're going to male your own case.

 

[HarryN]

For fun I looked up 40 lb force electric trolling motors.

The link that came up was for a minn kota endura max 45 trolling motor. ( so 45 lbs )

The rated current was 42 amps.

So ( 42 amps ) x ( 12 volt ) x ( 4 hrs ) ~ 2 000 watt - hrs.

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A typical example Li battery / size 27 is 100 amp-hrs, so

( 100 amp-hrs ) x ( 12 volts ) ~ 1200 watt-hrs

____________

To find the number of size 27s, a handy size to lift and move around ( not necessarily the cheapest )

( 2000 watt-hrs needed ) / ( 1200 watt -hrs per size 27 ) ~ 2 batteries absolutely drained down to the dregs.

___________

Ideally you will want to buy a battery actually rated for marine use with the vibrations encountered in a boat. It is not the same as something sitting in a room looking pretty.

Battle born and others make batteries in these ranges, or you could buy a single battery with the rating.

@Whinny is really good at estimating.......

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[SparkyGage]

Just some real word experience:
I am running a 3000lb sailboat with an 80lb thrust motor for up to 10 hours (longest run time yet) on a 100Ah 24v battery (2/5 to 4/5 throttle is the norm).

For a quick and dirty answer, I would think a boat that weighs less than half mine, pushed by a motor with half the thrust, and half the voltage, a 100Ah at 12v would be plenty of capacity for a day's fishing, even 50 if you are putting along the shore after using the outboard to get you there. More xxxAh, the less range anxiety. I would definitely get the ratings of your motor - particularly amp draw and get a battery rated for double that continuous load. And I would get a battery that the manufacturer specifically states as a trolling battery. (I've had a good experience with my iPowerQueen but that is the ONLY battery I've had experience with in this application.)

AND PUT A FUSE ON AND KEEP SPARES.

 

[Dave911]

Just some real word experience:
I am running a 3000lb sailboat with an 80lb thrust motor for up to 10 hours (longest run time yet) on a 100Ah 24v battery (2/5 to 4/5 throttle is the norm).

For a quick and dirty answer, I would think a boat that weighs less than half mine, pushed by a motor with half the thrust, and half the voltage, a 100Ah at 12v would be plenty of capacity for a day's fishing, even 50 if you are putting along the shore after using the outboard to get you there. More xxxAh, the less range anxiety. I would definitely get the ratings of your motor - particularly amp draw and get a battery rated for double that continuous load. And I would get a battery that the manufacturer specifically states as a trolling battery. (I've had a good experience with my iPowerQueen but that is the ONLY battery I've had experience with in this application.)

AND PUT A FUSE ON AND KEEP SPARES.

Redodos and Dj.... On amazon are good and test at rated capacity or moe. Moseworths are ok.
You probably have a variable speed throttle. Surge current really isnt an issue. Start slow and increase. Id buy a 100ah. Make sure it has a 100 amp bms.

 

[patrickparrott]

I have been using a 12v 54ah deep cycle Dakota lithium with my Minn Kota Riptide 70 for 2 years now on my 17'8" Maverick flats boat that weighs 1200 lbs. I usually am out for 4hrs minimum and use my TM most of the time that I am fishing. I have never yet reached the low voltage shutdown. It is not connected to my alternator and only charge it at home. Pretty surprising I know, with a 12v system that propels the boat at 3.5 mph when needed without a problem.