Can I hookup my boat electronics with a trolling motor?

[Ersteman]

Hey Guys,

I recently bought a used boat. I have a tiller style boat and my boat motor does not have any electronics. Am I okay hooking up the boat electronics (bilge, lights) and a rear trolling motor to the same battery? Anything I need to be concerned about with how I hook it up? I'm very new to this.

Thanks, Mike

[MN Fisher]

You should be alright - my old canoe I had the sonar, cameras and USB ports (camera and Tablet power) connected to the same battery as my MinnKota 30....never had an issue.

 

I do run 2 batteries now - one for the Edge 45, a second/smaller one for everything else.

[Susky River Rat]

When I had my canoe with a TM I used the same battery. I never had any issues. 

[casts_by_fly]

If you're running the fish finder at the same time as the motor there is a possibility that you'll have interference.  It depends on the motor and the specific unit and there's no way to predict it.  If its a problem then grab a small house battery later.

[MN Fisher]

^ If you do have some EMI/RFI interference on the sonar - it can usually be cleared up by putting a filter on the power supply to the sonar.

 

A Ferrite Ring Core is usually enough for low power (<24v) applications.

https://www.amazon.com/uxcell-Ferrite-Cores-Suppression-Filter/dp/B07YJWYKFH/ref=sr_1_9?keywords=ferrite%2Brings&qid=1691161862&sr=8-9&th=1

[airshot]

You mught find you need a bigger battery, depending on how much power you draw.  I used to have a group 27 deep cycle battery rhat ran my fish finder, radio, and nav lights at night.  Also my bubbler in my minnow bucket, and a small not often used trolling motor with no charging off my motor....and that would last all day with no issue.  A deep cycle battery would be a must, and a good charger to recharge after use use....

[Way2slow]

There's always a chance the TM can cause interference on your sonar display.  Doesn't hurt the sonar but can make the display do strange things.  Usually (if it does interfere with it) it will make black lines or dots across the screen when you run the TM.  

Getting a large enough battery would be the next concern if the motor is electric start only and keep it charged.  Not a lot of fun after running the TM for a while to go to start the motor and the battery is too weak.

Most small motors and older motors only have about a 15 amp charging system so it's not going to keep the battery charged if you use the TM much, don't care how long you run the gas motor, you will still need to charge your battery every time you come back home from using it.

 

 

[WRB]

Is the OB a pull start or electric start?

Whenever you use 1 battery 12VDC marine it needs to to charged at the end of the outing.

You should also have a 50 amp circuit breaker so you don’t fry your TM or  electronics ( sonar unit).

Tom

[Ersteman]

On 8/4/2023 at 9:52 PM, WRB said:

Is the OB a pull start or electric start?

Whenever you use 1 battery 12VDC marine it needs to to charged at the end of the outing.

You should also have a 50 amp circuit breaker so you don’t fry your TM or  electronics ( sonar unit).

Tom

Pull start. 

[Bankc]

25 minutes ago, Ersteman said:

Pull start. 

Good.  Then you won't need a "dual use" battery.  A regular deep cycle will be fine.  And even if you drain it all of the way, you won't be stranded.  

 

What kind of trolling motor do you have?  Does it have stepped speed settings (like 5 forward and 3 reverse) or is it infinitely variable?  If it has stepped speed settings, then it should be fine with the sonar.  If not, then it might cause issues.  But not every sonar and trolling motor have problems working off the same battery.  Typically, if it does, the easiest solution is to hook up your sonar to a second battery.  You can buy a cheap 7-12Ah 12v AGM battery for just the sonar.  Unless you're using a particularly large and fancy sonar unit, they typically just pull around 1 amp, so a 7-12Ah battery will last you 7-12 hours.  You might wear it out faster by draining it down all of the way so often (you're not supposed to drain a lead acid style batter below 50% capacity), but they're cheap enough that it won't matter.  And the smaller, lighter ones are much easier to carry.  

 

Also, check out the lithium batteries they out now.  Lighter, more power, and last longer.  They're more expensive, but it could be worth it for you.  

[Alex from GA]

All good answers.  If you're going to use your trolling motor for bass fishing it's far better to attach it to the bow.  I have a 14' boat with an electric start 25 and a 30 lb thrust trolling motor mounted to the bow with an L bracket.  No charging circuit on the engine but the battery lasts for a long time with a group 27 deep cycle battery.  Also a small fish finder on the same battery.

You have to turn the control head around for the bow mount, easy to do.