I have a question about how and why my batteries are connected the way they are.I had the battery covers off, and was gonna pull the batteries out to test fit a toolbox on the a-frame but alas, it won't fit between the propane tanks and the front of the trailer. Anyway, there's the negative from the first 6 volt, then a jumper to the second 6 volt, then the positive, making 12 volts. Makes sense so far, right?There was also a pair of 10 gauge wires with #10 studs jammed under the 3/8" lugs of the jumper cable. And it was red to the positive off the first battery and white to the negative of the second battery. I don't know what it's for, but as I see it, there's zero potential there. I'll post a pic of it for clarification shortly.Any ideas?

What you describe is the correct series wiring for 2 x 6 V batteries. The Negative from one 6 V is connected to the Positive of the other 6 V. The power output leads should be attached to the end posts of the two batteries, not on the two (-), (+) jumpers. That would be true for any lighter wires,as well.6 V's wired in series with temperature compensation sensor wire on jumper (as such, it draws no power):BTW, any fuses or circuit breakers in sight?

Temperature compensator?Turns out the pic I posted is in a double post... I'll put it here too.

What I see is a 6 volt source from one battery only. Is this a new trailer, or has it recently been worked on?

It seems that the trailer is operating on 6 volts. If you look in the middle of the batteries I believe that is the harness that feeds the trailer. The red wire should go to the plus with nothing on it and the white connects to the negative with the white on the other battery.

See where those wires go if you can, they may be the breakaway switch for the brakes. whatever it is, I think it's safe to say that you need to correct that wiring so it's connected to 12 volts. There isn't anything in the trailer that is any other DC voltage than 12v.

What are these wires for? | Good Sam Community

westend
Explorer
May 02, 2015
What you describe is the correct series wiring for 2 x 6 V batteries. The Negative from one 6 V is connected to the Positive of the other 6 V. The power output leads should be attached to the end posts of the two batteries, not on the two (-), (+) jumpers. That would be true for any lighter wires,as well.

6 V's wired in series with temperature compensation sensor wire on jumper (as such, it draws no power):

BTW, any fuses or circuit breakers in sight?
bigrigfixer
Explorer
May 02, 2015
Temperature compensator?

Turns out the pic I posted is in a double post... I'll put it here too.
SCVJeff
Explorer
May 02, 2015
What I see is a 6 volt source from one battery only. Is this a new trailer, or has it recently been worked on?
Ranger_Smith
Explorer
May 02, 2015
It seems that the trailer is operating on 6 volts. If you look in the middle of the batteries I believe that is the harness that feeds the trailer. The red wire should go to the plus with nothing on it and the white connects to the negative with the white on the other battery.
BurbMan
Explorer II
May 02, 2015
See where those wires go if you can, they may be the breakaway switch for the brakes. whatever it is, I think it's safe to say that you need to correct that wiring so it's connected to 12 volts. There isn't anything in the trailer that is any other DC voltage than 12v.
D_E_Bishop
Explorer
May 02, 2015
I'm with Jeff, it seems like someone has rewired your rig and you now have 6vdc supplying your trailer. My question is do all the DC circuits in your trailer work?

It looks to me like the battery cables were home made. Look at "The 12 volt side of life" website. It will give you all the information you need to set things up properly. I suggest this site because it is what everyone will tell you anyway and because for me having the drawing in hand is easier than having this thread printed out and in hand. Everything is on one page.

Good luck and try using some quality cables from NAPA or high end part store or automotive electrical shop.
wa8yxm
Explorer III
May 02, 2015
First the terminals marked ZERO VOLT are tied together with a 4GA cable so thy should be ZERO volt less there is a heck (hundreds of amps) Draw on the batteries

WHY there are small wires hooked to them I do not know..They may be mis-connected.

I would have to see it eyes on.
jrnymn7
Explorer
May 02, 2015
I see 3 small wires. One from the left battery's neg post, one from the left battery's pos post, and one from the right battery's neg post.

Is it possible the left battery is supplying 6v to something, and the neg wire on the right battery is a ground?
dougrainer
Nomad
May 02, 2015
1. Someone miswired and those wires should be 12 volt.
2. Some RV's have LOW and HIGH 12 volt lights in the RV (non LED). So, they use a 6 volt source to power the interior lights that are connected to make the lights "DIM". You usually have a 3 position switch for the affected lights. OFF--Then up supplies 12 volts to the lights and Down supplies that 6 volts.
3. It is VERY rare to have 2- 6 volt batteries on a Towable. So, I would bet the 12 volt original batteries were replaced with 2- 6 volts and those 2 wires not connected to the proper 12 volt terminals. Doug
newman_fulltime
Explorer II
May 02, 2015
smaller wires are for the electric tongue jack your missing a red wire that goes from the trailer to the pos post that is empty