I have an Minn Kota Ulterra trolling motor, 24volt, 80 lb. thrust. I have 2 new Optima blue top batteries, D27M, MCA-100, CCA- 800, AH-66, RC-140. I cannot troll for 1 hr. without my I-pilot remote showing my trolling batteries voltage is low and the remote stops working.
Any ideas why the batteries are running down so quick? Shouldn't I be able to troll for a longer period of time than this? I am not even running half speed.
Anyone else having issues like this?
When batteries are charged, what should the voltage be at the batteries?

I don't have the ulterra but have the terrova. I've had the 55# and now the 101#. I have never run the batteries down on either using it all day 10 plus hours. You should be running all day without an issue. I'd check the wiring to make sure that they are wired correctly and all connections are tight. I'd also stop by a shop and have them test the batteries and make sure that you don't have a bad one. It should be tested under a load not just the voltage.

Have a Ulterra 112 which is set up on 36 volt but can run all day and batteries still 50%.as previous post said would check batteries & wiring

Same here. I have three 5 year old blue tops and I have never had a problem.

I have a Terrova & 2 group 27 batteries, on my trolling motor lake I can run it most of the day and still have battery left. Also check your charger to make sure it's charging like it's supposed to.