Do you have a multiple bank charger? I have a 4 bank charger. My Helix 10 on the dash is attached to an accessory battery. I had a snowy image when running the Terrova, I pulled both fuses on charging wires to accessory battery. No snow. Pulling only the positive fuse made no difference. My accessory battery is only for dash electronics bilge and livewell pumps, power port on dash. My trolling batteries are only trolling and power port and Helix 5 on bow.