Deep cycle battery question

[zxninja]

I run a 55lb minnkota trolling motor and am going to install a second battery for it. At first I was going to simply install a battery switch to select the battery I want when the other dies. I am wondering if this is the way to go, or should I hook them up in parallel? What will get me the most life out of the two batteries before needing a recharge?
Anyone have experience with this?

 

[G.Mech]

I run my 55 lb Minnkota on a pair of deep cycle batteries wired in parallel and can get at least 10-12 hard hours on them without recharge. I think a good charger is the key to the battery life. I put an on board charger/maintainer on the boat which is really nice and self regulates the charging. I just changed the batteries after 4 years of heavy use but they were still doing a good job, I was just being proactive and I got a deal on two new ones (thanks Icefisherman!!).