Using Lithium Batteries for Cranking - Mercury Outboards

I recently contacted Mercury Marine and asked them for any information they could provide, regarding the use of Lithium Batteries as cranking batteries. I researched online and gathered information from different manufacturers as well.
This is the result of my research.

[rickss]

You are spot on with the fact that internet forums are the worst place to get information on any specific product. Making the change to lithium for my offshore fishing Yamaha jet ski regardless of forum naysayers. I'm installing a battery monitor/shunt where I will be able to monitor exactly what is happening in real time...anyone can ask me and I will be able to provide facts instead of useless opinions.

[derricklaw]

If LFP cells are below freezing temps, they can be damaged if you attempt to charge them. You can discharge them below freezing but not charge them. I use LFPs with a low temp cut off that won't take a charge until the cells warm up to above freezing. Some LFPs come with built in heaters too. Great video for the average consumer! Also, not sure if I missed it, but LFPs can take such high sustained charge rates that they can burn up alternators (not the other way around), especially at low RPMs where the alternator fan isn't spinning fast enough to radiate out the heat. Those are my only two helpful tips to add.

[AmericanPatriot-jjnh]

Wow that's alot of info on the topic. I've wondered about the electrical charging system and lithium batteries. Good job on breaking it down in simple terms.

[beavisbrowne]

Very intellectual and very valuable information. Thank you sir

[ADKMuskyFoolonFly]

Hey Paul, because of your research and very informative video and the knowledge I have, I just ordered my replacement batteries from Iconic to do a full conversion of my lead acid batteries to the Iconic lithiums-both the cranking battery and my trolling and electronics batteries. I got Ionic Lithium 12V 125Ah | Dual Purpose Starter Battery 1100 CA + LiFePO4 Deep Cycle for the cranking battery and two of the Ionic Lithium 12V 100Ah | LiFePO4 Deep Cycle Battery + Bluetooth for my trolling motor and fish finder electronics. I have a 2018 Ranger RT188 with 90HP Merc 4 Stroke. I just recently upgraded the trolling motor to the garmin force (24Volt) and the Garmin Echomap Ultra 126SV x 2 for the fish finders at the steering console and bow of boat. Will connect the two 100Ah batteries in series to get my 24 volts. Should be a good setup for my boat. Will be glad to get rid of the weight and maintenance of floating lead acid batteries. Again, thanks for the review and great information.

[ADKMuskyFoolonFly]

Nice succinct review. Thank you for the information and doing the review. Appreciate it.

[eliedube]

I have put a DL+ 135AH cranking battery on my boat powered with a 2023 Yamaha VMAX SHO 90HP. When the battery gets fully charged, the battery BMS shut the pwr input to the battery, and then the engine alternator creates a voltage spike that actually shuts down my hummingbird graphs. I'm not too sure if my engine has a stator or an alternator, but when it happens, I can actually hear a click sound coming from the battery or the engine and my graphs shut down at the same time... not to sure. So, actually, I needed to put a lead acid cranking battery and my lithium battery for accessories only. It was a pain in the neck, but I sorted it out with a traditional battery. Thanks for the info provided.

[muskietime]

Well done.
Gotta watch internet “Experts”.
Have had 3 Ionic Lithium 125ah batteries for my trolling motor (2) and Honda 200hp engine for two years. Zero problems.
I can now use the trolling motor more than twice as long as Li-Po4 batteries stay at full strength till just about drained.
I primarily switched due to the weight. Lifting 65 lb. batteries out and into the boat and moving them around is going to get me hurt and I just will not risk something I can’t avoid.
Only complaint is the issue of charging when below 32 degrees but I plan to use an oversized heating pad in the battery compartment to warm up the trolling motor batteries when cold.

Be well.

[Ted...youtubee]

5:05 that's what iwas told at the local boat show.
Stator charge, NO LITHIUM'.
What I did for a second lead battery charging, was install a second regulator (diode pack) in parallel with the original regulator.
2 boats since 1985, never had a problem.

[Aleoop]

A lot of good information thank you. So I just bought a mercury 9.9 with electric start and I wanted to use a Lithium Battery but from what that paper said and you have said that is not possible because this motor has a stater. And the only reason I am asking is you said that your motor also has a stater so can I use a lithium battery or not? I will still ask a mechanic, but I thought I would ask. Thank you again.

[MrFishhook]

Is your motor still working good with lithium cranking battery . How has ionic lithiums held up ? How is customer service ?

[stephvitacru]

Thanks for the info. Did you also research the fact that we are supposed to add a dc-to-dc between the engine alternator and the cranking battery. I have a Mercury Pro XS 115 and was told that we have to add a dc-dc else there is chance to blow up the alternator. So is the lithium battery a drop-in replacement or not ? I have a Dakota dl+ 135 ah. Thanks.
Btw, here is what we can find online on mercury website for the pro xs 115 alternator: Alternator Amp / Watt: 35 amp / 441 watt with water-cooled voltage regulator.

[bobsgradinginc.]

Stators can produce too high of a voltage and can cause the bms protection system to shut off the battery. Over voltage protection

Side note
I am using one lithium 12 volt ionic battery to start my diesel dump truck
Will eventually switch my marine engines to lithium. But was told by ionic lithium to avoid use with stator engines

[MrFishhook]

I have a 2023 Mercury 150 Pro XS . How do I tell if it has an alternator or a stator ? Response would be much appreciated

Thx for the video, there’s definitely lots of conflicting info out there. The 2 Mercury lead acid batteries that came with my 200 HP OB are just not cutting it for running 4 graphs, 2 live scopes, the boat stuff, and starting the motor. If I run on the trolling motor (36 V lithium setup) for 3 or more hours without starting the motor all the electronics drain the lead acid batteries down to low 11 V and I’ve had to use a Noco booster to start the motor more than once. Can I replace the 2 Mercury leads with 1 higher output lithium cranking or should I use 2 lithiums?

[RickSettle]

That's a lot of good information, IF the reader has a 4 stroke Mercury. I, and most likely many others, would assume that LiFePo4 batteries cannot be used with large 2 stroke Mercury engines even if they have high output alternators.

[Dfellers]

Well here’s my thoughts. For what it’s worth. Seeing how jump packs are made with lithium batteries and used to jump off your car or truck I’m quite sure it will be ok to use your lithium trolling motor battery to jump your starting battery. So long as it’s a 12v system not 24 volt.

[JimGrady]

Thanks for the great video and for showing us the information directly from Mercury! The internet has a lot of OPINIONS and a lot not based on fact. Question! I have the same motor from 2018 did you notice on the Mecrusy website under specs and intelligent power management it says the motor has an alternator but at the bottom of specs is say 35 amp / 441 watt with water-cooled voltage regulator? I wonder if that's on the new motors?

[alexz]

I have a 2005 mercury 115 two-stroke carburetor engine nothing fancy would a lithium cranking battery be ok?

[NeilGraham.I.M.F]

Man and us smaller boat owners get left out again. I really wish I could switch to a lithium starting battery. As I already have over 200 lb of batteries in my 17.1/2 ft aluminum bass boat. And don't have the space to spare for a fourth battery dedicated specifically for electronics. My poor battery compartment is jammed so full already. Especially because I just rewired with beefier upgraded wire the entire boat for my electronics setup. Garmin 106 at bow, Garmin 93 at console live scope Plus. Literally just turning on my Garmin 106 drains an Optima blue top " bought and installed two days ago" down to less than 12 volts before it even brings up the menu on the home screen. And that's just the 106. Not even running the 93 and the transmission of the livescope turned off