I have a 70lb minn kota maxxum 24V trolling motor on my 18 ft pontoon boat. I am trying to decide if I should go with two 12v lifepo batteries or  one 24v lifepo.  Do you think 50ah would be ok if I go with the two 12’s? We normally fish for 4-6 hrs on the lake.  

You need 8 LifePo4 cells to get you to 24 volts.  It doesn't really matter if the cells are in one case or two.  Two batteries would have two BMSs which would double the chances of a BMS failure but that's not likely.  If you have two batteries and one fails you might be able to use the other for something else.  For me the choice would come down to what fits in the boat the best and the cost.

 

I've never owned a pontoon boat so I'm not going to offer an opinion on how much power you need.

 

Without knowing your boat setup, my opinion would be 1 - 24V.  Two batteries are just 2 potential issues.  These batteries, as long as you don't go in the dirt price wise, are very reliable.  50 AH should be enough either way you go.

Do you have an on board charger and other batteries?  If so, I would stick with all 12v.  There are more options of straight 12V chargers.  If you’re going to have a dedicated charger for just this battery then it doesn’t matter.  

11 hours ago, casts_by_fly said:

Do you have an on board charger and other batteries?  If so, I would stick with all 12v.  There are more options of straight 12V chargers.  If you’re going to have a dedicated charger for just this battery then it doesn’t matter.  

I do have an onboard that charges the starting and house batteries (both acid) but the trolling battery(ies) will be at the front of the pontoon under one of the “couch seats” so it will have its own dedicated charger.

I'm in the process of deciding between 3 12V or 1 36 V and I'm most likely going with 1 36V LiTime even though it would require a different charger.  And through my research, 50 AH should definitely be sufficient.  

I have one 24V 60amphour battery and it is so much overkill for my needs.   I must have charge anxiety.

 

I'm on a kayak so the single battery is non negotiable.  but I think if you could, a single would be better.  that way you dont have to worry about the two batteries being the same health status.