LiFePO4 batteries for trolling motor

I am planning to replace batteries on my 36v boat for the next season. The concept of ‘more cheap throwaway’ batteries is appealing as I can basically get 3 new group 31 batteries for about 400 bucks total. Maybe a bit over that with taxes and such. The problem is, it seems like those are going downhill about as soon as you put them in and they seem to last 2-3 years before you start thinking about replacements again. I am wondering if switching to LiFePO4 is viable, and in researching that I have found a huge spread in prices for these batteries. I think a 12v 100ah lifepo4 would be an adequate replacement performance wise for a group 31 lead acid battery. In searching for 12v 100ah batteries, you can get them for in the neighborhood of 300 – 350 per battery all the way up to 900 per battery from Dakota Lithium. So my question is does the Dakota battery do anything different than a no-name from amazon? Is the difference in price just a warranty and some marketing? Does anyone have first hand experience with this conversion that they are willing to share? At 1200 bucks I would be a buyer if it meant more life, less weight and less size.

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I’m thinking of the same upgrade, but I can’t answer your questions on the quality difference between a $900 12v LiFePO4 and a $350 12v LiFePO4. I’d like to learn that as well. I would note that a 100 AH lead acid group 31 is roughly equivalent to a 50 ah LiFePO4 due to the LiFePO4 being able to maintain voltage at deeper discharge levels and higher overall efficiency. I’m looking at a 12v 60 AH or 12v 80 AH as an upgrade to my lead acid group 31 100 AH. Hopefully someone else can chime in on the reasons for the price difference. I do think the internal battery management system could be a factor which has built in safeguards to prolong the LiFePO4 service life

I would think the BMS current limit would need to exceed your trolling motor demand for it to work without shutting the batteries down when the draw gets high. You would also need a different charger to use the lifepo4 due to the 14+ Volts they need to reach full charge.

I’ve been looking at this too. I’m sick of the lead acid batteries dying in 2 years and constantly needing to maintain them. Plus, getting at the batteries in the nose of my ranger takes a contortionist.

Problems I have seen that have prevented me are needing a new charger and that cost. They are also prone to failure if you charge in cold weather. I keep the boat out year round and that’s an issue. Either need to take the battery out or get a warmer.

You would think the BMS would manage charging in cold weather? I know my milwaukee lithiums won’t charge if they are hot or cold. That could suck if you keep it outside though as it could just die on you in extended cold weather. There again though, no risk of freezing a lithium battery and the BMS just kills it to prevent it from fully draining and damaging the battery. Might be the best thing since sliced bread if you aren’t trying to actively use the battery in below freezing weather.

Next question would be could you replace the house battery with the same lifepo4 and have it start the big motor?

There are some apparent issues with using lithium for starting. Apparently the BMS can cause issues and the lithiums can impact charging systems. Mercury issued a service bulletin about them. Apparently they can void the warranty. There is also the inverse saying they are great.

I fish pretty frequently in below or near freezing temps. My boat also sits outside almost year round so that might make lithiums a non-starter for me. I’m going to call Dakota Lithium and talk to them about the options. If I get anything worthwhile I’ll post it.

I know there are a few videos on youtube of some guy testing out certain manufactures batteries for true spec. Which will give you kind of an idea of some manufactures doing things better than others. BMS also comes into play as well. Some will say they work as a starting battery for outboards but I personally won’t do it do to warranty voiding issues.

As for your trolling motor, I switched to Amped Outdoors Lithium 100ah batteries and I can say I am VERY happy with them. Customer service is top notch and have a good warranty.

Other benefits were the weight I dropped in the boat and the amount of runtime gained as well. Significate amount of runtime is huge!

One thing you have to pay attention to is your charger. Make sure your charger is capable of charging Lithium’s. I run the power pole charge system on mine and its honestly I believe the ultimate setup. Probably overboard but It’s worth it.

Lots of good brands of batteries, but I still think it comes down to the efficiencies of the internals and BMS when you get up there in price.

This will be my third season running dual 100a-h Battleborn LiFePO4’s with my Ulterra.

My only complaint is that they cannot be charged in freezing temps and I fish into late fall every year so this becomes a challenge in my detached garage. Also, in hindsight I probably coulda gone with two 50a-h and saved even more weight.

Both Battleborn and DL have relatively good service/support and warranty. I would never buy the knock-off crap. Two weeks after you buy it the vendor will disappear from Amazon’s website.

Regarding the charger – I custom ordered a charger from Dual Pro. I had them program the firmware to charge LiFePO4 on banks 1 and 2 and SLA on bank 3. No extra cost for that build.

J

Its like buying Energizers or Harbor fright brand batteries. You know the right choice. Harbor Fright AA batteries are 60% less in cost and have 60% chance of lasting more then 2 days. LOL

Well I don’t know the specific difference between the cheap ones and the more expensive batteries however do the research, there is a difference in the individual cell types, some being a 18650 vs 26650 style, and of course there are different quality grades of those. As well the BMS functionality is not the same over different brands. I used to run series 31 Interstate AGM’s but after 5 years they needed to be replaced at $350 each. I pulled the trigger on 4 Ionic LiFePo batteries, 3 – 100AH for the trolling system and 1 -125 with a built in heater for starting and electronics. I concluded they had the best BMS at the time and have a Bluetooth app that will give you the status of each battery including number of charges, state of charge, discharge/charge rate, all very useful. There is an 11 year warranty on the Ionic’s and in reality these batteries should last at least twice if not 3 times my AGM’s while providing 1.8X the power. Interesting, I lost at least 150#’s when I replaced the old AGM’s and my boat handled terrible until I put some weight from the back to the front. I never run out of power these days and to me they were worth every penny, even if they are almost $150 cheaper now than last winter. This was the first year I did not have to jump my starting battery because it had discharged past being able to crank over my engine when in Canada.

What did you do for charging your setup David?

Adam Steffes wrote:

What did you do for charging your setup David?

My Ranger had a Minnkota MK-460PC charger in it and using the AGM mode, it worked perfectly…..until last October on Leech, I secured the boat in my covered slip, plugged it in and left it. That night we had a pretty good electrical storm. No big deal but when I got home 2 of 3 of my trolling motor batteries showed 100% charge but one was only at 65%. Plugged it in at home and the 65% battery charge bank was blinking 2 yellow lights. Looked at the manual and there was not a code identified but it did say that if an electrical storm was possible to tilt the motor out of the water and unplugged the charger or damage could occur. I am pretty sure the lightning took out that bank. Ordered the new Minnkota MK-460PCL (L for lithium) and have run it on the bench. AGM settings work just fine, you don’t want a setting that does has an anti sulfation mode which is standard wet cell lead acid batteries.

I had the great luck of talking to a dakota tec .I was gonna get 2 100 ah with bms for a 24 volt ultera minn kota. He said I would only have 2.5 hrs of run time . Being new to lithium game I backed out when I learned I could get 100 amp for half price.I like to buy American if I can but not for 3 times the price. I’m confused now don’t know what to get. Any recommendations would be greatly appreciated.

I have been running a single 24v 100ah li time battery since winter. It is a no frills cheap battery but has done everything I need it to. It does not have low temp charging protection or self heating but being a single battery it is easy in and out when I use it in the winter.

https://youtube.com/@WillProwse
This guy does alot of indepth battery reviews.

Only ones I would consider are the Epoch ones as they are supposedly heated . They’re 15 brands or more of lithium marine brands all boasting the same big warranty . Probably all sourcing the same cells out of China, cannot confirm that , but seems like a rat race of brands coming out . . This warranty’s actually only a true 3 year then it’s pro rated . And how many of these companies are going to make it that long ? I’m probably too skeptical on it to be honest . I know guys that love them and I do think they are the future . I’m just not sure I’m ready for them yet .

Richard Duzan wrote:

I had the great luck of talking to a dakota tec .I was gonna get 2 100 ah with bms for a 24 volt ultera minn kota. He said I would only have 2.5 hrs of run time . Being new to lithium game I backed out when I learned I could get 100 amp for half price.I like to buy American if I can but not for 3 times the price. I’m confused now don’t know what to get. Any recommendations would be greatly appreciated.

2.5 hours? Is this based on running at level 10 for the full duration? I thought that I heard that it was not recommended to run above level 8 with lithium.

isu22andy wrote:

Only ones I would consider are the Epoch ones as they are supposedly heated

I have 4 non heated lithium batteries in the boat and have used them at 0 degrees once and below freezing lots. No problem. The heated feature is only for charging not for heating while using. I can heat my garage to 40 for charging the batteries

I was wrong I said 100 but it was 2- 60 ah.

Thank you isu Andy I didn’t know that was only for charging. Can you store batt.s in below freezing temp.s

This spring I switched to 2 amped 36v 60AH batteries wired parallel. They have been great and I probably went a bit overkill. The biggest test so far for them was a couple weeks ago on Lake Michigan trolling on a windy day I was running the trolling motor at 60%-65% for 8 hours trying to keep the nose of the boat pointed in the right direction. After 8 hours the app showed I still had 63% of the battery power left. I was pretty impressed with that. If I still was running lead acid they would have been dead, or very close at best to being dead. My only reservation is this fall if I am at a resort and it is too cold to charge them. I think I am going to add a couple of heated battery blankets this fall if it looks like it may be an issue. I may regret not buying batteries with a built in heater. At the time I bought my batteries, the batteries with the internal heaters I wanted were not available.

What kind of warranty are these lithium batteries coming with? I’ve heard as much as 10 years. I don’t know if you guys are buying them online or in person nearby, but I would definitely favor buying from a local retailer in the event I need warranty service down the road. The thought of shipping a battery for warranty service does not sound very appealing. Who knows how long it will take to get there and be serviced/replaced, and then shipped back out. I’d personally rather just haul it in and take care of it on the spot which would greatly reduce the down time.

The Amped warranty is full replacement for 3 years and prorated for years 4-5. With the ones offering 8-10 year warranty you need to read the fine print, and make sure you are really getting that long of a warranty.

I am waiting for the nuclear waste batteries to get a 24v 2800 year run time they say.

I had looked at LifPO4 batteries but cost did not work out for me. Menards Group 31 Lead Acid on sale and %11 off makes them about $101 and they are made by Deka for Menards. I usually get about 5-6 years out of my trolling motor batteries, so when I figure that cost dose not make sense for me. Now my dual purpose starting battery is a more likely candidate Running 3 12 inch helix`s that battery takes a beating if I get 3 years I am lucky so have been looking at 125ah and up to 1200ca Lifpo4 batteries.

Tom P. wrote:

Menards Group 31 Lead Acid on sale and %11 off makes them about $101 and they are made by Deka for Menards. I usually get about 5-6 years out of my trolling motor batteries, so when I figure that cost dose not make sense for me.

That is my line of thinking too. I get about 4-5 years out of my lead acid ones for $100 each. The up front cost for a lithium battery and the duration of life I would get out of it simply doesn’t add up right now. If they come down in cost, which I would expect in the future, then it might. Plus I’d also have to buy a new charger too.

How do you guys get 4-6 years out of your lead acid batteries? I get about 3 years and then they start to fade quickly. Do you just continue to run them as their run times shorten, and it isn’t an issue for you, or do you get a solid run time after so many years? With an Ulterra all I can think of the power dropping so low I can’t stow it. Just paranoid I guess I my part.

mojogunter wrote:

How do you guys get 4-6 years out of your lead acid batteries?

Obviously battery life can vary from person to person Mojo. I have 24 volt group 27 size batteries for my bow mount and the last set went for 4.5 seasons. You’re right it was pretty obvious when they started to go and I replaced them within a couple weeks.

My cranking battery lasted 6+ seasons. I don’t have enormous screens and I rarely use my lights, livewell, or bilge pumps. I keep a noco on board in case I need a jump, and I’ve never had to use it.

Most of my outings are not in heavy current and they are limited to 4 hours or less in tenure. I always recharge my batteries after I’m done fishing. I might upgrade to AGM batteries the next time as my charger can be used with lead acid or AGM.

If I had an Ulterra with auto stow/deploy I’d be more paranoid about it like you are too. Anything beyond 3 years with a lead acid is bonus time IMO.

Lithium batteries aren’t cheaper, they’re just nicer. Anyone pretending they are cheaper in the long run is just lying to themselves or their wife. I just went through it this spring so I’m kind of an expert right now.

Which part are you an expert on now? Lying to yourself or to your wife, or both?

tswoboda wrote:

Lithium batteries aren’t cheaper, they’re just nicer. Anyone pretending they are cheaper in the long run is just lying to themselves or their wife. I just went through it this spring so I’m kind of an expert right now.

I’m running 2-2012 Optima Blue Tops. This is the 2nd set I had last 10+ years. Before I go to Rainy next year, I’m not up for pressing my luck. I’d buy 2 more in a heartbeat but have heard they aren’t what they used to be. Moved to Mexico, maybe now made with lesser quality lead?? But still think I’ll set out the Lithium market and do 2 more agm till we see how lithium last and stand behind warranty. Weight in my boat is a non-issue. I fish 90% of the time by myself, at half throttle anyway. Although I may pick one up for the kayak. Running 2 flasher batteries that are getting tired.