Had a strange issue with my new Ultrex yesterday. this was actually my first trip out with it and I was really just checking it out and getting familiar. Stopped out in the middle of the lake, synced with the heading sensor and calibrated the motor. tested spot lock and some of the other functionality. Everything worked great with both the remote and the pedal. Picked up and went to another spot to check out the new live scope. Dropped the TM, hit spot lock and all was good. Tried the jog forward feature and it seemed to be working. Then started getting out a rod and after a minute or two I notice I'm drifting away from my spot. Remote still shows it's in anchor mode. When I tried to manually steer the motor, both with the remote and with the pedal, it wouldn't turn. If I turned the prop off I could turn the motor with the remote and the pedal but it turned very slowly. The remote showed an icon of a battery with an exclamation point inside it for the boat battery. So I figure I've got a bad battery. Or, possibly my charger has gone bad and didn't fully charge the batteries and the little bit i used the motor drained the battery. I get back to the house (several hours later) and get the volt meter out. All batteries test good. 12.6-12.8 volts. Test the TM leads going into the pedal and I'm getting 24.9V (24V system). Deploy the TM, turn everything on and it's working perfectly.

Now I know there are any number of things that can cause this from a battery that's not performing under load to water intrusion in the TM to a whole host of other things. My question is, has anyone seen this issue and can point me to where to start?

You need to load test the batteries. You could also have loose battery connections.

Is your TM on a circuit breaker? Mine does that sometimes because the breaker gets corroded. I flip mine off and on 5 times before I get in the water every trip and that seems to clean it off enough I don't have any problems! Otherwise it does same as yours. When I hit spotlock it looks like its anchored and quits when the motor revs up to catch up to the anchor point.

Yes that's exactly what mine is doing. Don't have the breaker installed yet but that's good info. I'll check for corroded wires and connections. I'll also load test the batteries.

And check the ground wires. I had an intermittent issue that turned out to be a ground wire to the battery. Terminal connector was not properly crimped on the wire; only the shrink wrap holding it. Problem didn't show up till 1 yr after purchase of the boat. Crimped the connector, re-applied shrink wrap and all is well.

Update just in case someone else comes across this issue.

Turned out it was a corroded wire that jumped the two batteries for the 24V system (corroded on the POS side). New wire and all is good! Had it out Saturday and it worked flawlessly.

Thanks for all of the advice.