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.