lithium trolling motor batteries

[FireDriver]

I have 16' aluminum boat with a 50hp 2 stroke mercury and a 24v motorguide i3 trolling motor.  I'd like to upgrade my trolling motor batteries to lithium as the lead acid just do not last very long.  I generally use the trolling motor to steer and the main to push while trolling.  I was looking at 2 12v 100aH batteries but didn't know if that would be overkill.  Any info would be appreciated. 

[TBinKC]

I can't speak for motor guide TM's but I have a 36V MinnKota and have 2 50AH batteries on a 20'Lund and fishing a typical day with a lot of trolling motor operation the most I've ever consumed in a day has been about 40% after 100% charge.

So everything being equal, I think it is slight overkill for me. This issue may actually be whether you typically plug in the charger every time you get off the water. Lithiums are best operated in the 30-70% range. So ideally you would be operating (best for the batteries) on the 2nd day of a full charge. Unless you have other use for the 12V part of the system you could consider 1 )  24v 50 AH battery. That would allow future expansion if needed. Of course you would need a 24V charger... If you're motor is 12V electric start (or if you're considering it) make sure you get lithiums that are capable of that too. My jump to lithiums was frought with months of this same process I'm sure you're going through. I don't regret my decision to go to lithium.. so the real question is the configuration and it looks like you're there now.  There's a guy fisherman named Goodman on you tube that does a good job of explaining things. take a look at his stuff for goo info too. It helped me. Good Luck.

[go4bigfish]

I have a Lund Fisherman  1750 with a 24v Ulterra, and I use 2 100ah lifepo4 batteries. I have a 2 bank Noco onboard charger connected. I use my trolling motor for autopilot while trolling. Never had an issue with battery life, and can go at least twice without a recharge. I would go for the 100ah as opposed to the 50ah. You can't have too much reserve and the price difference between them is not significant. The new mini size profile is nice - I have three of these, two for trolling motor and one dedicated electronics supply