Battery Setup Help

[Erawk]

Hello Bft friends.  I am upgrading my 15' aluminum starcraft and need some insight and advice. 

I recently bought a minn kota Terrova 55 Ipilot and now I am thinking of adding a starting battery and a multi-bank on board DC charger. Why? Well Minn kota is very adamant that the battery bank used for trolling motors is not used for anything else because fish finders using the same batteries as the trolling motor will display interference.   I don't know about the trolling motor,  but I do see a lot of static/interference on the fish finder when running the outboard at higher rpms.  I assume what I see is electrical interference from the outboards alternator since it is connected to the same batteries as the finder.  Is this correct?  This is causing me to consider my options for isolating the systems/batteries. [bobdumb]

I currently have two 29 size deep cycle batteries running parallel for 12v power which powers everything in the boat... outboard starter,  fish finders, lights and trolling motor.  I am getting much better run time out of the two battery bank than I ever did with a single.  It's also less taxing on the batteries because I don't run them as low as I would a single battery.  I do know however that using deep cycles to start motors is bad for the battery. [pirate]

All of my systems will be 12v.  I'm wondering if I should leave the trolling motor,  lights,  and fish finders on the parallel 2 battery bank,  or split the trolling motor on one battery and put the finders/lights on the other single battery.  I'm thinking that isolating the systems between the 2 deep cycles and the starting battery is the best bet,  but I like having two batteries run the trolling motor.  Or should I get a multi purpose deep/cranking battery to run the fish finder and starter and keep the two battery bank for only the troller?


 What are the pros and cons?  Any tips or tricks? Thank you all in advance. [fishon]
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[wiperhunter2]

"should I get a multi purpose deep/cranking battery to run the fish finder and starter and keep the two battery bank for only the troller"

This is exactly how I have mine set up and I have a minn kota 55. I use two 27 size deep cycle batteries running parallel for 12v power, I can run it for 6 hrs at a little over 5.5 speed, with no problem. I don't have any problem with interference on my fish finder while running my main motor on the same battery, do you keep the power wires separate between your main motor and your fish finder? How old is your Starcraft? I've had two older Starcraft with Merc motors and I've never seen that problem as long as you keep the wires separate.
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[Erawk]

[quote wiperhunter2]", do you keep the power wires separate between your main motor and your fish finder? How old is your Starcraft? I've had two older Starcraft with Merc motors and I've never seen that problem as long as you keep the wires separate.[/quote]
thanks for the reply, WiperHunter


They each have separate wires running to them of course, but they were on a common circuit. All of the accessories were run off a circuit switch panel which I intend to keep. The boat is an 87 with an 89 mariner (yamaha) 30hp 2 stroke.

If I go the same route as you (2 DC's in parallel for tm/ 1 hybrid for starting/lights/finders), would a 2 bank DC charger be OK or would I want a 3 bank?

Thanks again. Any and all constructive input is greatly appreciated. Thanks for reading.
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[wiperhunter2]

According to the Mini Kota web site and talking to a guy there about their chargers, each battery should have separate battery charger leads, even if two of batteries are hooked together. I guess a two bank charger would work but they would not charge as fast, so they recommend a three bank charger. I can not say with 100% certainty that the way you have you fish finder(FF) hooked up is the problem but when I installed mine late year I hooked it directly to the battery, I just make sure I turn it off when I load my boat. If the wires run too close together they could cause interference, so separate the wired from the FF and any other power source as much as possible, some companies say 6", if possible. The instructions on installing my FF say," In order to minimize the potential for interference with other marine electronics, a separate power source may be necessary." To see if this is what is effecting your FF, try hooking it up to a separate battery, just to see if it makes a difference, while running your main motor. If the interference goes away, then you know that was the problem and you can takes steps to correct the problem, if it doesn't then something else is the problem. The reason I was asking how old your boat/motor is was because all newer boats have alternators and it could also be that it is going bad, so the interference could be coming from your alternator. By the way I think Mercury makes the Mariner motors.
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[Erawk]

3 bank it is then. Thanks. I see what you mean now about putting some distance between the wires when routing through the boat.
I'll try what you mentioned next time I'm out. These Mariner motor were built for Mercury by Yamaha. Says made in Japan on it. Good motors from what I've read. [fishon]
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