I hadn't maintained my batteries for a while, and they ran out of juice last time out. When I got back they were both so low on water it took 3/4 gal of water to fill up... Will exposed cells create interference? 

 

I also recently bought a new Lowrance Elite 9ti (hooked to MG Xi5) and have been having interference issues, but I've done a LOT to address this: standalone battery, transducer cable runs opposite trolling power cables, transducer mounted properly on transom, clip on rf chokes at both ends of tm power wires and transducer cable, and common ground between 24 and 12v systems. Having its own lawnmower battery definitely helped, but there's still something giving a small amount of interference. 

 

Not sure what else it could be. Batteries are full of water now and I'll be going again soon. It blows my mind since the depth finder is its own complete separate system from the boat now. Any ideas or experience on this would be awesome.

I know the power control module in the trolling motor itself gives off interference too. Maybe that's it. Is there anyways to address this? 

Low voltage on my batteries causes my depthfinders to shut off.  When I was having interference problems between my trolling motor and my depthfinder I changed the frequency from 83 to 200 on the depthfinder and the interference stopped.  Have you contacted Motor Guide to see if they could help?

1 minute ago, Scott F said:

Low voltage on my batteries causes my depthfinders to shut off.  When I was having interference problems between my trolling motor and my depthfinder I changed the frequency from 83 to 200 on the depthfinder and the interference stopped.  Have you contacted Motor Guide to see if they could help?

Not yet, I have not had a chance to do it while I was on the water. The main issue seems to be when I am actually using the trolling motor. With everything that I have done to separate the depth finder system from the starting battery and trolling motor batteries I just don't see what else I can possibly do as far as that.

 

What I was thinking was since the trolling motor batteries were the ones that were low, maybe the motor pulling such a strain on batteries that have exposed cells would somehow create more interference. 

 

Is there anything you would recommend on top of what I have already done?

Aside from changing the frequency from 83 kHz to 200 kHz (or the opposite) on the settings of your depthfinder,  I don't know of anything else to try. Except to contact Motor Guide. It is possible that the armature or the brushes in the motor are going bad which could generate excessive sparking inside the motor which is generating the interference. 

That makes sense. It amazes me they don't shield this stuff at the factory. We shouldn't spend thousands on electronics only to have issues.