Trolling motor

dlane

dlane

Active User
Registered
Joined
Sep 27, 2014
Messages
3,123
Just woundering what the y’all think about running a trolling motor from 12v dewalt tool batteries. I want to put a trolling motor on a kyack and don’t want to use a heavy boat battery, it’s a 30lb thrust motor , small kyack, I’ll have 3-4 batteries, any better options what say you ?.
 
Lithium would be the best, but I'm guessing these aren't it. Try them and see how long they run
 
Thanks, of corse the longer they last the better, I don’t have the dewalt or whatever batteries , I was just woundering if there was a lite alternative to boat batteries that would last. With the rite components I could build my own battery?.
I do have a paddle :D
Was also thinking a solar charger off the back
I have fish to catch , when they have fishing tournaments they let the big ones go behind my house every week.
 
I have a MinnKota 35 lb. thrust motor that I have run from a home-built PWM controller for more than thirty years. For most of the use, power drain is minimal and an 85 amp-hr battery is good for a couple of days. Running at full power can drain a battery fairly quickly though. I don't recall the current demand off hand but I believe that it is in the 30+ amp range. I experienced that a couple of years ago when I was fighting a heavy wind and after a half an hour of running, there wasn't enough left in the battery to start the outboard.

Most cordless power tools are good for 2 - 3 amp-hrs. A set of four would provide around 12 amp-hrs which would drain fairly quickly.
I would consider rechargeable lithium cells for the highest energy/weight ratio. 18650 cells, the type common to laptops, are a possibility. However, particular consideration to balancing the cells and fire protection. Other cell configurations are possible as well.
 
Our neighbor has a fishing kayak that is pedal powered. It leaves his hands free for fishing. It is quite seaworthy and he has taken it into the Gulf of Mexico and the Gulf of Alaska.
 
Couple of random thoughts here ...
1. The batteries that John (matthewsx) posted a link to are 7 amp hours. Don't know about DeWalt batteries, but I've seen Milwaukee 18 volt drill batteries with up to 5 amp hour capacity. Don't know if the trolling motor would be happy with 18 volts, but it may be a possibility. Amp hours are the key number you'll want to look for. RJ said his 85 amp hour battery is good for a couple days. Let's assume he meant three days. So for one day's use, you should probably plan for about 25-30 amp hours of total capacity.
2. Most tooll batteries nowadays are lithium ... probably lithium polymer (LiPo). Cautionary note - LiPo batteries can get hot if discharged too far - even catch fire. Modern drills that use such batteries generally have "smart circuits" that will stop the drill before depleting the battery too far. There's no such circuitry on a trolling motor! You might be better off using lead-acid batteries (like the one John posted) or lithium ION. You can do a quick web search for more info on LiPo batteries and their hazards.
 
I would not use cordless tool batteries. Look at electric bike battery packs or build your own battery pack out of 18650 batteries using 18650 battery holders (there are many battery holders available for building custom 18650 battery packs). Either way I think you would get much better information for your project from a DIY electric bike forum.

I have some old Metz camera flashes that I love but the replacement custom batteries are ridiculously priced! I built my own replacement battery packs out of 18650 batteries and some off the shelf battery holders. My battery packs outlast the original battery packs many many times over (I have never actually exhausted one of my battery packs).

If you cut apart your Lion tool batteries or any laptop batteries you will most likely find that almost all of them are made from 18650 batteries. If you are talking about Nicad tool batteries... they really just suck! I have replaced all my Dewalt 18v nicad batteries with 20v Lion batteries and my Dewalt 18v cordless tools run MUCH better than new!

P.S. 18650 Lion batteries are 18mm in diameter and 65mm long.
 
Last edited:
If you go forward with the DIY battery pack using the 18650 or similar battery be sure to keep in mind that Not All 18650 batteries are the same! They can have different Amp ratings as well as difference in how quickly they are allowed to discharge that should be matched to the job. Meaning you can get a fast high power discharge or a much longer/slower reduced power discharge depending on which brand you choose so be sure to double check this spec before purchasing.
(not sure if im using the correct terminology but hopefully you understand what im trying to explain)
 
Latinrascalrg1 said:
If you go forward with the DIY battery pack using the 18650 or similar battery be sure to keep in mind that Not All 18650 batteries are the same! They can have different Amp ratings as well as difference in how quickly they are allowed to discharge that should be matched to the job. Meaning you can get a fast high power discharge or a much longer/slower reduced power discharge depending on which brand you choose so be sure to double check this spec before purchasing.
(not sure if im using the correct terminology but hopefully you understand what im trying to explain)
Click to expand...

Correct. Some 18650 batteries are designed to provide a very high current for a short time. Other 18650 batteries are formulated to not provide near the maximum current but they will last for much longer. Samsung is a popular 18650 battery manufacture. They have many different models of 18650 batteries intended for many different use cases.

Like I said above, there are DIY electric bike fanitics that live for building the ultimate battery pack for their bikes. I would reccomend tapping into that knowledge base.

Be careful about letting ANY high power density battery pack get wet and shorting out. Google a youtube video on shotrting out a Lion battery... they put on a very impressive fireworks show!

P.S. I believe the original Tesla vehicle used 18650 batteries in its battery pack.
 
Last edited:
You must log in or register to reply here.
Back
Top