12v 100ah kayak battery for trolling motor (weight is a big factor)

[Dagman]

Hi Folks,

I'm new to the group and have some basic knowledge of batteries but not a ton of experience building them. I've wired cars and have done the wiring and setup of my travel trailer so I know how to research and apply the knowledge. I have been reading and browsing youtube etc. but haven't seen a weight savings comparison of buying vs building a battery. Right now I use a sealed AGM which of course weighs a ton. I'd like to get the battery down around 20 pounds but the commercial batteries weigh in close to 35 pounds. I just watched a video of Will's that claims you can build one that weighs just over 20 pounds but it was an older video. I was wondering if someone could point me to resources that might be more current for building your own 12v 100ah lithium battery. I was hoping to keep it around $300-400 bucks but am flexible. And yes, I'm searching and finding some things but as always, there is a lot to pour through and I'm going as fast as a I can. Travel trailer battery is next.

I'm not asking anyone to do footwork for me, just hoping you might have a link or two that you found useful that I can explore as I research on the site.

Thanks,
Darren

 

[Browneye]

100A cells are pretty cheap, a 100A bms isn't bad either. Some wire and a case, fuses and such, you should be able to meet your budget, or close. My 230A was about double that. Just make sure that's enough juice - seems a smaller trolling motor pulls about 30A at full power, so maybe 3 hours-plus running.

I've messing about with boats for my entire life, especially like small boats - they're just so much fun, and a lot less headaches than yachts. LOL
I have to say, if fifteen pounds of weight is gonna make or break your setup, you're likely to have bigger problems.

My late grandfather took a canoe several hundred miles down the Yukon river in AK. Probly over forty years ago - he drove the Alcan hiway five times before it was paved.

Good info here on building a battery - I would not have attempted it without the help of this forum. Nothing too complicated, but some critical points nonetheless. Read up and jump in. You'll need a power supply for top balancing - happy to lend you mine, just pay for shipping - they run about $70.

You'll need a lfp compatible charger - I've come to really like the Meanwell chargers, but the Victron IP series are also very good. They're all kind of spendy.

Docan has a sale this month, they have the bms too, although a lot of folks including myself, went with Overkill Solar for their pre-programmed and tested JBD bms.

Overkill bms: https://overkillsolar.com/product/4s-bms-120a-lifepo4-threaded/


I got the 230A Eve cells about a year ago, outstanding product. They run the house loads for a Winnebago motorhome.
Looks like 100A cells are $71 each. I don't recall if they're paying shipping or not, but I think they are. Amy Zheng has a lot of happy customers.

 

[Dagman]

Awesome, thanks for the info. The 15 pounds won't break the project but I carry this battery by hand a couple hundred yards at a time and the lighter the better. If I can shave 10 or 15 pounds I'm all about doing it. I have a lot of gear on my angler kayak and weight, along with space are the biggest factors where improvement makes a big difference.

 

[Browneye]

Ah...makes sense.
For some reason I had 'canoe' stuck in my head from a previous thread on this subject.

The angler kayaks are dabomb. A pic or two would be great.

What kind of motor?
LFP is all the rage for those. Lots of power and no voltage sag. Build it into a plastic box to be water resistant. Another previous question was electrical danger from swamping - there isn't any.

 

[Dagman]

It is a small 30 pound thrust transom mount (https://minnkota.johnsonoutdoors.com/us/shop/freshwater-trolling-motors/endura). I may go with a motorguide Xi3 bow mount in the future but for now I'm upgrading the battery to be more convenient since the current battery is about 4 years old now as well. I have a PWM unit and a remote for power, forward, back. I have cable foot steering hooked up. I don't have any great pictures of it currently but here is how I mounted it.

 

[TacomaJoe]

This thread mentions a 20lb battery.

Beginner Friendly "Plug-n-Play" Lithium Batteries

Battleborn, Ruixu, Simpliphi, Kilovault, Trillium, Renogy and more!

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