Interference with cranking battery?

I've have always had a seperate, but very small battery for my 1197, which would not last all day, and produced an amazing picture, but now i have rewired and am running the 1197 from my cranking battery 31 series. i tapped 12volts from one of the two batteries in my 24 volts system. works great for all the 12 volts i need, but is now making a little interference when i run the big motor. It's kind flashes screen in a minute amount in time with plugs firing. It looks like i'm gonna have to go back to a small isolated battery for the 1197, which is what i tried to get away from in the first place. any sugesstions? thanks guys in advance. jm

A battery in a 24V series connection is most likely a trolling motor battery, not a cranking battery. It would be unusual to have your cranking battery in series with another battery.

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Originally Posted by jmack

I've have always had a seperate, but very small battery for my 1197, which would not last all day, and produced an amazing picture, but now i have rewired and am running the 1197 from my cranking battery 31 series. i tapped 12volts from one of the two batteries in my 24 volts system. works great for all the 12 volts i need, but is now making a little interference when i run the big motor. It's kind flashes screen in a minute amount in time with plugs firing. It looks like i'm gonna have to go back to a small isolated battery for the 1197, which is what i tried to get away from in the first place. any sugesstions? thanks guys in advance. jm

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I would think that your interference is coming from your trolling motor battteries. I would suggest running your 1197 off of your cranking battery only. One other thing you can try. If you have downloaded the latest software you can go into the Sonar menu and go down to the Nosie filter and see if you increase the noise filter to see if this corrects the issue.

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Originally Posted by Joby @ Humminbird

I would think that your interference is coming from your trolling motor battteries. I would suggest running your 1197 off of your cranking battery only. One other thing you can try. If you have downloaded the latest software you can go into the Sonar menu and go down to the Nosie filter and see if you increase the noise filter to see if this corrects the issue.

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Funny he is saying he only gets the problem with the big motor running. I don't know of many people that run the big motor and the trolling motor at the same time???

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Originally Posted by Fisherman_Wantabe

I don't know of many people that run the big motor and the trolling motor at the same time???

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That's actually a relatively common approach to boat control up here in the northland. A kicker motor provides most of the thrust and the bowmount does the steering. Tighter turns and better performance when trolling into the wind (b/c you're steering by pulling from the bow, rather than pushing from the stern).

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Originally Posted by CatFan

A battery in a 24V series connection is most likely a trolling motor battery, not a cranking battery. It would be unusual to have your cranking battery in series with another battery.

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You are exactly right, its unusual, but thats the way i'm running it. the cranking battery, "IS" one of the trolling motor batteries, i only have two batteries and am running a 24v trolling motor and have tapped off 12volts from one of the batteries in the 24v system to start engine, run lights, and electronics. when i said i only get the interference when i run the main engine is exactly what i mean. if im just sitting or drift fishing from the back of boat, without cranking the main engine, there is no interference at all on the 1197. I'll try the noise filter setting first, then add another battery if needed. hope this is a little clearer now. sorry for the confusion. jm