what batteries to get and where

[Titan8750]

Endend up replacing the new battery with another new battery same issue. There are two ground wires for each side both look good and tight. What's weird is when I physically swap the batteries it's always the old battery that starts the boat. Does not matter if old battery is physically battery one or two location.

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[bturner]

Unfortunately not a big surprise there.

Okay, so let's take inventory of what we appear to have learned here.....

• We now know that we have 2 good batteries.Based on this we can eliminate the battery as the issue.
• We know that you can start the boat with the original battery but only the original battery.
• It sounds like you have a 2 position switch and no isolator.
• You have 2 set of cables going to both batteries. We need some picture of this.

If it were me I'd be looking real hard at the wiring to make sure you have them hooked up correctly. Since you just bought the boat I would not assume that red is positive or black is negative or that the positions are correct. I would trace the wires back to the source and confirm that they are what you think they are. Not a fan at all of the simple dual battery switch as in most installations (it can but in most installations I've seen) it doesn't isolate the house and start circuits. This would seem to be the case with yours as you're able to start the boat from either position. From here I would try would be to start the boat with the switch in position 1, new battery in position 1 and the leads disconnect from the battery in position 2. You need to be really careful here that the leads are separated and can't contact anything that can conduct power. Or a safer version would be to "reduce to the ridiculous" and eliminate the battery switch all together and run the main leads directly to the new battery. This should work and will tell you if it's something in the switch, a cabling configuration issue or a connection at the switch that is causing the issue

Below is a diagram of what I think you have wired in. Notice that both the grounds on the batteries are tied together. Does yours look like this. I'm also including a picture of one of the installation I did some time ago for physical reference. I'm kind of wondering if your grounds are not tied together and you're seeing a ground potential difference between the new and old batteries as they're not the same. This would tend to explain why battery 2 would not light up the dash and only click when you tried to start.

[bturner]

Note that in the wiring diagram and in my installation both grounds are physically attached. This ensures the ground potential is the same throughout the system.

[Titan8750]

Note that in the wiring diagram and in my installation both grounds are physically attached. This ensures the ground potential is the same throughout the system.

I took the boat out this past Sunday and had issues with loss of power. Once I filled the ballest up the boat could barely plane. So I just took it to the local Nautique dealer to have everything looked at. Thanks for all the advise. Greatly appreciated.

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