Boat voltage on downriggers

[stratofisher]

I just put a Black Box on my boat and found out that my natural voltage is 1.01 volts. I disconnected everything in the boat from the batteries and it is still 1.01 volts. Guess I don't have any leaks because it didn't change, but still have higher than the normal .7-.8 volts. Any ideas on what is causing this higher voltage and how I might lower the natural voltage. I checked it with the black box, and also my Fluke meter. Same regardless. Just a little lost on this boat voltage thing. By the way the boat is an Aluminum Custom Weld Jet boat. I have a kicker motor that is bonded and had no impact whether up or down when I tested.

 

[Bduck]

SuperD just went thru this with his boat. He did some rewiring of his accessories running seperate power & ground wires with a new fuse block. This lowered his voltage sunstantially. Making sure all ground connections are clean helps too.

 

[Metal Manipulator]

Check your zinks. They must be firmly attatched to the hull and clean.

 

[remembering]

Check your zinks. They must be firmly attatched to the hull and clean.

I was going to say the same thing. They are also called sacrificial plates or anodes. As they get old they will cause a charge on the hull of the boat that can translate to other things like the DR.

 

[stratofisher]

I will cleanup the zincs and do a check. I just ordered a new plate to replace one of the ones that was looking bad. Hope this will bring everything into check. All the wiring looks good and didn't appear to change anything whether connected or not. Probably a zinc problem from the sound of it.

 

[MMDON]

You have a bad ground wire somewhere that is grounding to the hull. If everything was disconnected your boat would read zero.

 

[lowe1648mt]

First rule of electronics- check the ground.

 

[SuperD]

In a boat, isn't the negative post of the battery the ground?

 

[MMDON]

In a boat, isn't the negative post of the battery the ground?

It's supposed to be the only ground.

 

[bfloyd4445]

one thing often overlooked is voltage drop accross connections between bonding points and battery terminals. I know they look fine but clean them anyway then your battery terminals then check your voltage. another source of problem is the use of non marine wireing in boat construction or when adding after market equipment. They sell marine grade wire for just this reason. When purchasing wire make sure it says on the package, marine grade. A battery is simply two dissimiliar metals and an electrolyte like a river, lake, ocean. Most good boat manufacturers use marine grade but not all.

 

[bfloyd4445]

It's supposed to be the only ground.

and the only ground. In marine applications the boat chassis is never part of the system like with cars, trucks. every device must have two marine grade wires one from the - and one from the + terminal of the battery. At no point is the ground connected to the hull of the boat if aluminum unless it is electrically isolated. A proper bonding system is a completely diferent circuit. Marine alternators and starter motors are electrically isolated from the metal of the boat, engine.