Connect wire to positive or negative?

[Dwight Lindsey]

I've just changed our house batteries from flooded lead acid to Litihium Ion Phosphate.  I installed three 206 amp batteries.  In order to get them to fit I needed to remove the pull out battery tray.  So . . . I had to remove the chassis batteries as well.

Unfortunately, I didn't note the position of one of the wires connected to the chassis battery.  It connects to a wall mounted fuse and the other side of that fuse disappears into a hole in the corner of the battery box.

In the attached picture, the wire with the yellow plastic that's connected to the wall mounted fuse, connects to the battery.   Positive terminal or negative terminal?

I suspect that this is a transmission related wire, but I don't know that for sure.

Advice?

Dwight 

[96 EVO]

Hopefully someone more electrical than me answers, but I've never seen a fuse on the ground side.

[Tom Wallis]

1 hour ago, 96 EVO said:

Hopefully someone more electrical than me answers, but I've never seen a fuse on the ground side.

Agreed. No reason to fuse the ground wire. It has to go to the positive post. As a matter of fact you can read BAT on the fuse next to that cable. That woulds always be positive.

Edited October 8, 2022 by Tom Wallis

[Craggar]

Looks like a circuit breaker to me and would go to positive.

 

[MyronTruex]

That is indeed a 12 volt auto resetting breaker. You should be able to see the value stamped on the housing somewhere. 

They are not expensive and that one should be replaced for good measure. The connections are looking bad for sure and 12 volts just does not have much push to work through bad connections. Even if you don't replace it, take the nuts off and wire brush the connections and sand the connectors. 

Yes connect it to the positive side of the batteries. 

It is very rare to fuse a negative lead but is sometimes done, though I have not seen it in too many years to remember. 

[Dwight Lindsey]

I bought a new 12 volt 20 amp breaker at a local auto parts store and connected the loose wire to a positive terminal of the starting batteries.  Nothing smoked, nothing blew up . . .

[MyronTruex]

Just put a test light or voltmeter onto the terminals. It should light up on each post. If there was a short the breaker would likely be clicking on and off. 

[wamcneil]

That looks like the circuit breaker that feeds the Domestic Hot terminal block in the front run bay. Domestic Hot bypasses the battery disconnect switch and is always hot.

Cheers

Walter