Resistance between negative DC battery and bonding circuit

[CMJ]

Hi All,

I'm just trying to track down a couple of electrical gremlins and have just measured a resistance of ~50ohms between the 24V DC battery negative and the anode/metal bonding circuit (on an Azimut 50, 24VDC).

Is this normal? Something tells me it's not.

thanks for any help.

 

[JerryC]

It should be less than one ohm. The make/model of boat is immaterial.

 

[superheat6k]

No not normal, but likely a corroded connection somewhere along the bonding circuit, possibly several bad joints.

They are typically jointed with soft crimped Yellow terminals. These do not react well with salty water. I am in the process of replacing my bonding circuit using crimped and soldered joints at each lug.

 

[Assassin]

As above, corroded terminals or even battery connections.

Remove the battery connectors and check them first, ensure they are clean and smooth and make a good connection and cover with petroleum jelly, you will be surprised how many battery connections come loose or corrode.

Check all connections as standard cable blackens over time and the cores snap which reduces their effectiveness, crimp and solder is my preferred method but only use rosin electrical solder and spray the connection with a little Waxoyl as this is electrically inert and great for electrical connections; you can also cover the connection with PIB or self amalgamating tape for total water exclusion.

 

[CMJ]

Many thanks everyone for your help and I'm glad to hear this is not normal as wasn't sure if there was supposed to be a determined resistance for some reason. Some of the bonding terminals are corroded so will replace these plus the wiring next week and hopefully that'll then resolve these gremlins I've had.

 

[Rocksteadee]

You will no doubt find a high resistance corroded joint in the most inaccessible place.
There are only 2 ways to make an electrical connection on a boat. One way is using tinned wire with crimped and soldered joints then sealed with glue lined heat shrink........the other way is the wrong way