Battery issues

[jenga]

I just recently bought a used boat and I was told to use a deep cycle battery for my trolling motor and a starter battery for my motor.  I am also going to hook up a new fishfinder, I was wondering should hook up the fishfinder to the same battery as the trolling motor or the starter battery.  If I run it to the starter battery will I take a chance of wearing the battery done then I would be unable to start my motor.  Any info would be great.

Thanks,

Jenga

[Tin]

You would be surprised how little electricity a fishfinder uses, I have mine on the trolling motor batteries and never had an issue.

[tntitans21399]

Their are three types of batteries.  Deep cycle, dual purpose, and starting.  The differences are, I'll use a standard battery, is the spacing between the metal plates inside of them.  A deep cycle's plates are farther apart so the current doesn't move as fast which is great for accessories (lights, fishfinder, etc..).  A starting battery has plates closer for a lot faster current for starting a motor, because the bigger the motor the more cranking amps you will need.  A dual purpose is between the deep cycle and starting, they can start the lower HP motors (I have a 55HP) but they might not have enough cranking to be able to start the bigger 150+HP.

I actually have my fishfinder, running lights, and a seasense dual light all on during the night from about 7/8pm to about 3am before and I still have about 40-50% of the battery left.  I use a deep cycle on my trolling motor and a dual purpose battery on my main motor (and all the acc. I said earlier) and I haven't had any problems.  Just make sure to charge them as soon as you use them so they will be fully charged and help them last longer.  And the good thing about having two batteries is if the main motor does out you then have 2 batteries to get you to a safe place of back home because a trolling motor is about the most dependable thing on your boat, well for me so far.

[Team_Dougherty]

You may experience interference, when the trolling motor runs, on your depth finder if it is hooked up to the same battery as your trolling motor.  

I do not think you will have to worry about running down your starting battery with your depth finder during a regular fishing day.

A good read on batteries

http://www.windsun.com/Batteries/Battery_FAQ.htm

[flechero]

I run all the 12V stuff off the starting battery... gps and graph are on all day sometimes the livewell also.  My advice would be to buy a good dual purpose for the starting battery and never give it a second thought.  (all of my boats have been wired this way and never had trouble)

FWIW, I've never had trouble even with cheaper wal-mart batteries on a 175hp with all the accessories. (it's a 13 year old boat)

[Bud]

                  Their are three types of batteries.  Deep cycle, dual purpose, and starting.  The differences are, I'll use a standard battery, is the spacing between the metal plates inside of them.  A deep cycle's plates are farther apart so the current doesn't move as fast which is great for accessories (lights, fishfinder, etc..).  A starting battery has plates closer for a lot fster current for starting a motor, because the bigger the motor the more cranking amps you will need.  A dual purpose is between the deep cycle and starting, they can start the lower HP motors (I have a 55HP) but they might not have enough cranking to be able to start the bigger 150+HP.

                               

Not exactly    You need to read the link Team_Dougherty posted it is right on.

http://www.windsun.com/Batteries/Battery_FAQ.htm

[dale]

Your trolling motor causes a flux in amp draws from it's power supply that will effect any other electronics attached to the same power supply.

Dale

[Wayne P.]

I've been "fluxing" my electronics for over 30 years with no problems. After a long cold day, I may have a low voltage cut-off of the electronics, but that is the only symptom that has occurred.

[Team_Dougherty]

I am not sure about "fluxing". I am sure that some trolling motors that have have electronic speed controllers, not the ones that have resistors to control speed, the multiple on/off cycles in a second can cause "static" on depth finders.

[dale]

wayne you are right.... So can you tell me why my lorance unit gets fuzzy when I step on the trolling motor button?

by the way it quit when I moved the lorance unit to my cranking batt

Dale

[dale]

exactly TD  THanks

dale

[Wayne P.]

Dale, I have not experienced that symptom and can only speculate. You may have a minimum size battery or aged battery that experiences a lot of voltage drop when the trolling motor is in use. Another cause that used to be a problem a long time ago is interference from the circuitry of vairable speed motors.