Structure Scan/ Terrova

The downscan & side imaging screens on my HDS-10 dim when the 80 lb. Terrova I-Pilot is running. The higher the trolling motor speed, the more the screens dim. Dimming is more prevelent in 800 mode, but also present in 455 mode. The traditional sonar screen and the mapping screen do not dim. All other HDS-10 & LSS-1 features that I use seem to be working fine, with the possible exception of some lag when selecting different screen combitations.

The HDS-10 with 4.0 software, Structure Scan, Network and two LMS units are on a dedicated circuit that is connectd to the starting battery and separated from all the other boats wiring. All three batteries were just replaced with no impact on the situation observed.

Is the dimming a normal occurance? Anyone with a similar experience?

Thanks for any responses.

John

Sounds to me like your depth finder is hooked up to the trolling motor batteries. Try hooking the depth finder up to the starting battery

That was my first thought, but he said it is hooked up to the starting battery.
DT

Your getting interference from your trolling motor. You don’t have to be on the same battery to get interference. You should probably try to install a ferrite choke (RF kit). I think Johnson Outdoors (who runs Minn Kota and Humminbird) was giving them away or selling them cheap at one time. I have not heard if they still do but you could call 800-633-1468 to inquire. otherwise I think you can still get the kit at Radio Shack etc.

You might also make sure you have a large enough wire to your motor (10 gauge or better) and make sure everything is grounded well.

Wade: Thanks for the quick response. I used 6 gauge marine wire & a 60 amp Minn Kota breaker, so that should not be the issue. I will check the ground wire. Additionally, the Terrova is a factory reconditioned unit purchased this spring.

I’ll also get the RF kit when I get home. I have no experience with the RF kit-is it connected to the trolling motor wiring, the HDS, the LSS-1 or the circuit powering all my electronics? Is it connected to the positive or negative side?

John

Are your wires running parallel to each other? I run my trolling wires on one side of the boat and fish finder cables through the other side.

Sandmannd: Crawled around today and found one place where the 12 volt power & network cable to the stern mounted 332c cross the 24 volt trolling motor wiring. The 332c power wire runs back to the same fuse block that powers the bow mounted 332, the helm mounted HDS & LSS-1. The NMEA network is connected to everything and the network is powered through the same fuse block. I separated the wires as much as I could without surgery,about 5″, and went for a trial. No change. Is there a minimun separation? The boat is a 17′ Lund Fisherman. The fuses are located under the helm. It was easier to get to the port side stern by routing through the bow.

John

After a bit of experimenting, it appears that the interference is coming through the 3 bank battery charger. When I disconnected the charger leads to the starting battery, 95% of the interference went away.

Interestingly, the interference was worse at slow trolling motor speeds and barely perceivable at full speed.

When I get back to Wisconsin I’ll get material for in-line switching of the positive & negative charger leads for the starting battery. This will enable me to isolate the stating battery from the charger when needed. Think I’ll still get the ferrite choke, too.

Thanks for the ideas. I’ll give an update in July.

Turns out I have a bit of an issue with the battery charger, but the charger was not involved in the interference problem.

The real problem was a blown fuse in the brown ground wire within the Terrova. Minn Kota TA suggested that if the unit did not have the Universal Sonar, I would need to run an additional ground from the motor. It does have the US2, so I checked the wiring diagram and saw a ground with a fuseholder. Checked the fuseholder and sure enough, blown fuse. Replaced it and now all is well in the world of Side Imaging and Down Imaging.

When I took delivery of the unit, it ran backwards because the black & red wires from the I-Pilot were reversed at the factory. I connected them correctly and it ran the right way. The brown ground wire fuse must have blown when the black & red wires were reversed.

Thanks to all who offered assistance.

John