ulterra run time ???

I up graded from a 14 foot boat with no trolling motor on it, to a 2007 Alumacraft navigator 175 tiller with an Ulterra 80 # 24 volt on it.  I was wondering  how long the batteries will last? Looking for an average time.  I know it depends on wind waves and speed. Right now I am getting about 5 hours out of it. Is that about it or should it be longer? Do I need to replace my batteries. I don't know how old the batteries are,no stamps or engraving on them.

Get the biggest batteries you can whether they are group 29's or 31's.  Get the biggest AMP hours that you can, and make sure that both batteries are the same make, size and age.  Then charge them up after each use.

Depends on your usage..... I find I can go a LONG time on setting 4 or 4.5. I use the kicker to push and the bow mount at that setting for steering. If your trying to pull cranks and running it at a high setting with the bow mount alone it will obviously not last near as long.

Thanks guys  I am just going to change out the batteries and go from there.

Replace the batteries. Should get more then 5 hrs. 

Depends on battery type and Ah rating.  Plus the shape there in.  But if you have the Ah rating and there in good shape you can start calculating.  There is an amp draw chart.

1) The best way to test your batteries is to charge them fully.  Then after 12-48 hours, check them with a multimeter.  A new battery should read 12.7.  A good battery is 12.5-12.6.  A battery is starting to need replacement at 12.4.  This is a better test than load testing them.  

2) My 70# / 24V Powerdrive will troll Green Bay at 3.0-4.0 speed for 10-12 hours without an issue.  I am guessing longer because it only took 10 hours to recharge them.  

My guess is your batteries need to be replaced.  

Pull your batteries and have them load tested, my guess is one is bad.  With two batteries the system is only good as the weakest battery.