Lithium Trolling Motor Batteries

Hey Crew,

Looking for some real world results from those of you who have to switched to lithiums for your trolling motor. I’m looking at the Ionics. I run a Skeeter WX 1910 with a 36v Ulterra. I troll a lot on the river with the trolling motor on 5 or 6. I’m leaning towards 3 of the 100ah 12v Ionics to replace the interstates. They sell a 50ah set but I’m guessing the river would chew those up in a few hour running the trolling motor on 5. I’ve done quite a bit of reading on the amp draw but I’ve also read reports/reviews of users saying they are trolling all day on the 50s with 30-40% left. So based on that I want to hear from those of you who have them. How are you using the trolling motor and how much juice is left after a 6-8 hour outing. Thanks!

Also interested. I don’t fish the river much but have been thinking off going this way to drop some weight in the boat.

I don’t have lithium but the reason you get longer run time with them is because they can be almost completely discharged whereas a lead-acid can only be discharged about 50% before the voltage drops to unusable levels. Based on that a 50AH lithium would probably just be about the same as a typical ~100AH lead-acid battery when it comes to run time.

Edit: lead acid AH rating are almost always 20hr rates though and it’s actually going to be less at higher discharge rates like a trolling motor would use. Lithium capacity doesn’t degrade as much with higher amperage so I guess a 50AH lithium would be a bit better than a 100AH (interstate srm-31 is 98AH) lead-acid but not sure it’s enough to be worth the money solely for run time. I can’t find a spec-sheet for interstate that shows AH for different discharge rates to see exactly what the difference is. Trojan though, for example, says this for one of their deep cycles:

5-Hr Rate – 85 AH
10-Hr Rate – 97 AH
20-Hr Rate – 105 AH

The 5 to 10 hour rates would be more useful for trolling motor usage and at 5hr you’re down to ~42AH usable making the lithium maybe 20% better at best. At 10hr rate you’re pretty close to even.

Got The Ionic 100AH this spring, the biggest thing for me was shedding about 150lbs out of the front of my boat. I was running group 31 AGM’s I never had a problem with them, but wanted to cut out the weight in my boat. as far as run time its pretty crazy how much longer these last. I am a musky guy by heart and just recently was able to really test them out. Fished for 8ish pretty hard hours on the TM with a good bit amount of wind. Mind you I have a AlumaCraft 205 Competitor sport, so it catches lots of wind. At the end of the fishing session I was only down to 86%. I also really like the Ionics for the Blue Tooth connectivity, its is pretty interesting to watch amp draw and how different factors play into it. All in all, I dont have that much time on them yet, but so far they are awesome! As you can see by the picture, they are pretty small, and the compartments of the 205 are not that big, I used the packing foam they shipped in to make it work for now, Will be getting a better battery box soon.

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John Rasmussen wrote:

Also interested. I don’t fish the river much but have been thinking off going this way to drop some weight in the boat.

The reduced weight is the biggest selling point right now compared to a standard battery. The up front cost is not worth it yet though. When the price drops, then it may be.

Right now you’d be paying about 4 times the cost (or more) for a lithium compared to a standard battery, but you would not be getting four times the life.

I keep looking at them but the lack of low temp sensor or charging is a deal breaker so far for me. There are batteries with low temp sensors and or a heating element but that raises the price significantly.

Will the onboard charger for the lead acid batteries work with the lithium batteries?

Cooperman wrote:

Will the onboard charger for the lead acid batteries work with the lithium batteries?

The Ionics will work wit a Min Kota Precision which I have. I am considering getting the charger from Ionic as well for another $400 because it is designed specifically for the lithium batteries and will charge them in 2 hours.

I have the Minn Kota charger, when I initially got the Ionics, they had about 25% charge on them, the Minn Kota brought all 3 up to 100% in about 3ish hours.

I plan to switch my cranking batter to lithium when it gives up the ghost. Probably the same with my trolling batteries- swap from a two 12V in series to a single 24V lithium.

Unless they all go out at once, in which case I won’t be getting two of them unless i hit the lottery. I’m hoping the cranking battery goes bad about 2 years before the trolling batteries.

I was thinking the same thing today Russ! Your post answered my question. Any good “real world” comparisons for run-time versus lead/acids? I added a Amped Outdoors 60ah for my electronics house battery and it has been awesome. In past, bow unit (helix 12) would start to drop below 12 volts post 2 hours, now with lithium stays at consistent 12.5 volts all day long.

I have 3 100 ah for my trolling motor. 21.5″ fiberglass deep v with 350. So heavier than yours. Most all my fishing is on the river. I’ve had them under 10% from about 8 hours of spot lock in heavy current. Used them yesterday bed fishing about 6 hours running at 7 or 8 power between spots. Used about 60%. Most of what you read on people using 50s are bass boats that weigh less and and have much lower drag in the water. This is with a minnkota. The new brushless motors are more efficient so can’t speak to them

Thanks for the input onthewater! 100ah it is. Appreciate the input!

Truthfully,I would spend a little extra and get 3x125ah with the heated option if you fish cold weather.Just make sure battery charger will charge at 32F or colder.The PP Charge shuts off at 32F regardless of battery construction.So I have both batteries and charger leads in an insulated box,a few hand warmers keeps things happy below freezing.

This year I bought the 80 ah from amped outdoors. Running a 36volt in a 2060 skeeter. Been on p4 with it and mill lacs. Put in some 10-12 hour fishing days and no loss of power, while leads on the river for me would get about 8 hours when new. I used to compensate with using the kicker in high winds or fast current to get longer run time on lead, but have not had to do that this year with lithium.
Downside to lithium is they must be above 32 degrees to charge. I have a heated garage, or you can get the heat packs like what battle born sells.
I plan on getting a small 12v 200watt electric heater to stick in battery compartment for my trip to lotw this fall. Hope this helps!

They sell heat mats that are temp controlled for plant growing in cold weather. Two for about $25 and use about 12 watt ea.

Musky Ed wrote:

They sell heat mats that are temp controlled for plant growing in cold weather. Two for about $25 and use about 12 watt ea.

Or you can get a lithium battery with integrated heater pads controlled by the BMS. The BMS monitors cell temperature. If the cells are below charging temp (32′) when a charging cycle starts the BMS diverts the inbound current coming from the charger to the heat pads and starts to warm the cells. Once the cells have reached a safe charging temperature the BMS diverts the inbound current back to charge the batteries. Total cost increase between a heated and non-heated version of the same battery is $50.

Trying to evenly heat internal battery cells with a low-temp external pad just doesn’t seem like a great solution in my book.

https://norsklithium.com/product/100ah-12-8v-lifepo4-heated-deep-cycle-battery/

KPE wrote:

I plan to switch my cranking battery to lithium when it gives up the ghost.

Will an alternator even charge a lithium? I just looked at the link James posted, HOLY COW, they are spendy little devils.