Battery Switch

breshlsu63

Cadet
Joined
Mar 9, 2005
Messages
9
What accessories should be pulling off the cranking battery, and which accessories pulling off the deep cycle?
 
Last edited:

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,198
What accessories should be pulling of the cranking battery, and which accessories pulling off the deep cycle?
What is your goal in adding a second battery?

If the goal is a guaranteed "Start", the starting battery should be stand-alone, with nothing but the engine powered from it
 

breshlsu63

Cadet
Joined
Mar 9, 2005
Messages
9
What is your goal in adding a second battery?

If the goal is a guaranteed "Start", the starting battery should be stand-alone, with nothing but the engine powered from it
The second battery is strictly for a trolling motor, but the way it is wired with the cranking battery and a 1/2/All battery switch, it appears that everything is pulling off both batteries, and I fear that while fishing, I might pull the cranking battery down as well.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,198
The second battery is strictly for a trolling motor, but the way it is wired with the cranking battery and a 1/2/All battery switch, it appears that everything is pulling off both batteries, and I fear that while fishing, I might pull the cranking battery down as well.
They are only pulling off "both" batteries when the switch is set to both. Otherwise, the load is carried by battery 1 or battery 2 as noted on the switch
 

breshlsu63

Cadet
Joined
Mar 9, 2005
Messages
9
They are only pulling off "both" batteries when the switch is set to both. Otherwise, the load is carried by battery 1 or battery 2 as noted on the switch
My tilt/trim motor and accessories work no matter what the switch is set to. But either way, if I’m trolling, I would need both batteries ’on’ since typically a depth finder, tilt/trim, aerator, and bilge work off the cranking battery tied.
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,228
Starting batteries typically control anything that pertains to the motor, including the trim and tilt. Anything not pertaining to the motor is on the house battery. Trolling motors should have their own dedicated batteries. How big is your boat, motor and trolling motor. The size and draw on each will determine how big or how many batteries you need.
 

breshlsu63

Cadet
Joined
Mar 9, 2005
Messages
9
Starting batteries typically control anything that pertains to the motor, including the trim and tilt. Anything not pertaining to the motor is on the house battery. Trolling motors should have their own dedicated batteries. How big is your boat, motor and trolling motor. The size and draw on each will determine how big or how many batteries you need.
17’ aluminum bass boat with evinrude 88spl.
 

breshlsu63

Cadet
Joined
Mar 9, 2005
Messages
9
Your boat has serious wiring errors.
Well, why do 2 battery switches have 2 inputs, but only 1 output? It seems like it defeats the purpose unless you’re solely using it for a double bank. I think what I need to do is have two separate battery switches.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,198
Well, why do 2 battery switches have 2 inputs, but only 1 output? It seems like it defeats the purpose unless you’re solely using it for a double bank.
The purpose of the switch is two fold.....it allows you to charge both batteries with a common source, and it allow you to connect the motor and "accessories" circuit to either battery if necessary.
I think what I need to do is have two separate battery switches.
If you want a particular circuit to draw off a particular Source, the battery needs to be isolated and the circuit wired directly to the Battery.

In this situation, an ACR is typically used to charge the "isolated" battery.

1738695006737.png
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,228
According to the battery engineers I know, your battery or batteries for your trolling motor should be deep cycle and preferably charged from a deep cycle charger, not charged from your outboard motor charging system for best performance and longest life. The start only battery will recover from the motor charging system. No electrician here, but, I do believe your boat wiring is not done correctly, while it may work, doesn't mean your getting the best out of your batteries nor adding to their life expectancy.
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
482
Well, why do 2 battery switches have 2 inputs, but only 1 output?
More on this: your entire load of the boat including the trolling motor and starter for the outboard (OB) are all feeding off that one output from the switch and your wiring is probably fine. As mentioned, the selector switch allows you to decide from which battery (1, 2 or both) that the entre load will be connected to. See this link for more explanation on these types of switches.

This is a suggested operating protocol:
  • When starting the OB, select to 1, the start battery.
  • Once at station and OB is shut down, select to 2, the deep cycle battery for trolling.
  • Once done trolling, reset switch to 1 for OB staring and trip home.
  • Start battery will recharge with OB alternator.
  • Once docked, select OFF and charge the deep cycle with plug in appropriate charger.
Notes:
  • As highlighted above, if select BOTH for trip home hoping to charge the deep cycle this may shorten the life of the deep cycle and not properly charge it.
  • This protocal also ensures your start battery is not drawn down and will be available to get you home.
  • If only repositioning (not a trip home) will still need to do the switch back to 1 for starting the OB and then once at station and OB off, back to 2.
  • If back to 1 and start battery too weak to start OB (should not happen) then select 2 and try the deep cycle and if still no go, try both.
The above protocol may be a pain > always needing to select from 1 to 2 and back to 1 when starting up the OB but that is how it appears this boat was wired up. However, if the switch is easily accessible, just need to develop this habit.
 
Top