27 or 31 series batteries for new Fortrex?

[blazin461]

This year I bought a new Minn Kota Fortrex 112 for my boat. I have not gotten it installed yet, but it's a huge upgrade from my current Maxxum 74#. My current 74# runs on two 31 series batteries and are now 7 years old and need to be replaced. My question is: Now that my new motor is 36V and needs 3 batteries, can I go with 27 series batteries, or should I stay with 31 series batteries? Will it make a difference? I would love to switch to a single 36V Lithium Pro battery, but the cost is ridiculous, costing more than the trolling motor itself?

What is the real difference between 27's and 31 series? Do 31's provide more power? or is it a matter of longer run time?

[221champ]

following

[LainTx]

I have my 36v system ran with 27 series batteries and have never had an issue with them dying before the day was done.

[bandit53]

Blazin, for a TM application you should be looking at the reserve capacity (RC) of a battery. Not all batteries of any given size are equal, but generally speaking a group 31 will have a greater capacity than a group 27. I believe if you buy 3 sufficient RC group batteries, you will be fine. I run a 36v, 112 Ultrex on 3 group 27 Northstar AGM batteries. Before the Ultrex I have a 36v, 101 Fortrex on the same batteries, which are now 6 years old and still as strong as ever. I am no battery expert, so someone will greater technical knowledge may chime in, but I believe if you get 3 group 27 batteries, each with a RC of 190 or better, you will be fine, provided you properly maintain them. An example would be a Trojan SCS 200. Another good choice (no personal experience, just what I have read and been told) would be a Deca group 31 AGM from Sam's Club, which goes for something slightly less than $200.

[bandit53]

One more thing to consider is a group 31 is physically larger than a group 27. That may affect your selection given your available mounting room.

[CatFan]

This year I bought a new Minn Kota Fortrex 112 for my boat. I have not gotten it installed yet, but it's a huge upgrade from my current Maxxum 74#. My current 74# runs on two 31 series batteries and are now 7 years old and need to be replaced. My question is: Now that my new motor is 36V and needs 3 batteries, can I go with 27 series batteries, or should I stay with 31 series batteries? Will it make a difference? I would love to switch to a single 36V Lithium Pro battery, but the cost is ridiculous, costing more than the trolling motor itself?

What is the real difference between 27's and 31 series? Do 31's provide more power? or is it a matter of longer run time?

Longer run time.

[blazin461]

Thanks for the input gentleman. Greatly appreciate it.

[Meadows]

One thing I've learned with TM batteries is this. For the amount of money I spend on fishing tackle, tourney entries, gas in boat, boat payments, etc..... It's extremely foolish to skimp on the cost of TM batteries and have all that other money wasted because your day was cut short because your TM died.

I learned the hard way.