battery

kevgle

Active Member
Joined
Jun 11, 2018
Messages
44
Reaction score
12
Points
8
i didn't take note of previous hook up before I removed them so I need some help.replacing batteries on a dual battery setup.I know the negative terminals are connected with a jumper are the positive connected as well.If not I have a red wire that Im not sure where it goes Thanks
 

Gulffisher

Well-Known Member
Joined
Nov 29, 2012
Messages
78
Reaction score
22
Points
8
Hard to say without more info. Single or dual engine? Do you have a battery switch of some type? If so, is it "on-off" or "1, 2, both"? Do you have onboard battery charger?
Go to Blue Sea System website for battery and switch wiring diagrams.
 

SkunkBoat

Well-Known Member
Joined
Oct 12, 2017
Messages
4,235
Reaction score
1,467
Points
113
Location
Manasquan Inlet NJ
Website
www.youtube.com
Model
Express 265
Get the Grady manual for your year/model. There will be a diagram of the original battery and switch connections and "Accessories" circiut breaker

If no one has changed anything, that will be what you need to do.
 

kevgle

Active Member
Joined
Jun 11, 2018
Messages
44
Reaction score
12
Points
8
its 2000 265 express twin yamaha looks like batteries were connected together.just want to make sure this is correct.Dont have grady manual.Do have switch on/off 1,2 both
 

SkunkBoat

Well-Known Member
Joined
Oct 12, 2017
Messages
4,235
Reaction score
1,467
Points
113
Location
Manasquan Inlet NJ
Website
www.youtube.com
Model
Express 265

DennisG01

GreatGrady Captain
Joined
Sep 1, 2013
Messages
6,825
Reaction score
1,210
Points
113
Location
Allentown, PA & Friendship, ME
Model
Offshore
i didn't take note of previous hook up before I removed them so I need some help.replacing batteries on a dual battery setup.I know the negative terminals are connected with a jumper are the positive connected as well.If not I have a red wire that Im not sure where it goes Thanks
Explain that better. It's not clear what you are talking about or referring to.

Post some pictures of what you're talking about if your manual or other things people have posted don't clear it up for you.
 

kevgle

Active Member
Joined
Jun 11, 2018
Messages
44
Reaction score
12
Points
8
skunk boat that is exactly it .Thank you hope you get in the water soon
 

seasick

Well-Known Member
Joined
Aug 19, 2008
Messages
9,146
Reaction score
1,311
Points
113
Location
NYC
For two batteries, there has to be a ground to each from the two motor feeds. There has to be a jumper between the two negative posts.
There has to be a ground or more than one ground smaller gauge wire for accessories. This may have been wired onto a separate ring terminal or the grounds may have been wired into the same lug as the motor ground. Its easy to tell jusy by looking at the big lug terminals for more than one wire.
There will be a big positive wire to each battery that goes to the battery switches.
There will be one or more smaller gauge positive wires that connect directly to one or both batteries depending on hoe bilge pumps were wired. That's the basics. Note, connect the positive cables first and the grounds last. That is a safety measure to avoid a catastrophic short should your wrench bump into a grounded post or other grounder pece of metal while tightening the positive connections.
 

SkunkBoat

Well-Known Member
Joined
Oct 12, 2017
Messages
4,235
Reaction score
1,467
Points
113
Location
Manasquan Inlet NJ
Website
www.youtube.com
Model
Express 265
skunk boat that is exactly it .Thank you hope you get in the water soon
download the manual from https://www.gradywhite.com/explore/grady-owners/owners-manuals/

also, do you have Aux Charging wires from your yamahas? They would be a third wire 10 awg along with motor starting cable. It may be a 3 part cable or the aux may be a separte red 10awg in a black sheild. They may be going to the pos battery terminals but they may be hidden on the battery switches. They may be connected cross motor so that the port motor also charges the stbd bank and vice versa.
 
Last edited:
  • Like
Reactions: Peter A

Peter A

Well-Known Member
Joined
Jul 12, 2023
Messages
93
Reaction score
32
Points
18
Age
61
Location
New Jersey
Model
Adventure
Just a word of caution which you may or may not need…

If you are uncomfortable with the concepts behind 12v electrical systems or if there are questionable wiring configurations then disconnect all the negative battery cables until you confirm proper configuration. Nothing like a voltage surge to damage engine or other boat systems.
 

kevgle

Active Member
Joined
Jun 11, 2018
Messages
44
Reaction score
12
Points
8
I do have aux battery charger that is connected to deep cycle positive.Should be ok Thanks
 
  • Like
Reactions: Peter A