Lithium Batteries / charger for Boat

[SkunkedAgain]

The Minnkota onboard chargers are lithium capable. They are also capable of charging dissimilar circuits, for instance your 12v starting battery and your 24v trolling motor system, simultaneously without the need to separate.

As for your AH question, battery life all depends on the size of the boat, how much wind, how hard you're running the electric, etc. 100 AH is a good sized battery and should last a long time.

I have a 36v 100 AH LiPo in my boat. The Minnkota was not capable of charging a Li of that much voltage, so I had to buy a dedicated golf-cart battery charger, but for two 12v, you'll be fine with a regular onboard charger.

Appreciate the info, guess I already pulled the trigger on the NOCO charger, so I hope it will work well... Understand the usage sets the life on the charge, but was looking for an estimate of if this would be big enough... I have a 18' Tracker so it's not terribly heavy, but it does have a wind profile that will probably catch more breeze than my old tri-hull... so it will take more power, but I also plan on using it as an aid, not the main propulsion, more for steering and anchoring purposes and slow trolling... I think my old wet cell battery was a 72 amp hour and I haven't used it on this boat, but on the old one, it was a little weak to last all day, but that was on a 12 V motor and a single battery, so with two at 100 amp hour I'm thinking it should have a fair amount of power...  

I'll have to try and see if the charger will work without disconnecting the jumper, that would sure be a lot easier and part of the reason I got the on board charger, but if it won't the battery is easy to access...  Is this the reason folks use a battery cut off switch?  Or is it to avoid shorts that set your boat on fire??? Just wondered if you could put a switch between the batteries and cut that circuit off while charging them.... Then I wouldn't have to mess with the wires... sorry random thought... I'll bet that would work.... Anyway thanks for all the  info, I appreciate it... Jeff

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I was talking to the guy at Backwater Sports, they are the Minn Kota Service center in North Orem.  I was thinking of replacing my 36Volt system with Lithium batteries when the current Wet cells die.  He did not recommend using Lithium because the tend to burn your motor out.  He said if you do go to Lithium, do not run the motor over 80% .  Now I did not ask if he was talking older motors with brushes or both with or w/o brushes,  but thought that was an interesting piece of information that no one talks about !!  I still have 2-3 years left on my current batteries,  so I am not gong to worry about it.  But do some more research on it before you invest,  might save you not only the price of Lithium batteries, but also a new motor !!!

Yikes I hadn't heard anything like that... Hope I don't find out the hard way.... Wonder what the reasoning is with that?  Will the lithium provide the ampage too fast so it overheats the motor??? Hope this doesn't turn out to be true, but I'll have to watch how hard I push the motor, I wasn't planning on using it at full power, but I know the spot lock sometimes gets over aggressive at trying to keep you on spot... Might need to watch out for that... Thanks for the heads up on that... Jeff