Very Hot Battery Wiring - Advice please !

[AngliaUSA]

2006 - 26/19 with two 6 volt lead acid golf cart batteries (about 18 months old) wired up to give the rig 12 volts. One battery reads 6.7 volts the other 5.9 volts - When connected together I am getting a steady 12.7 volts at the main black and white wires - but they are getting so hot and smoking that I immediately disconnected them for fear of the wires melting and a fire. I’ve traced the main 12volt battery supply wires all the way under the rig to the power supply panel and am only getting 6.7 volts at the input connections on the panel - no visible signs of a short, bad ground or damage to the wiring - any suggestions on what I should do next ? Perhaps the control board has gone bad ? Thanx in advance-

 

[jagizzi]

I would guess that there are a couple of problems here. The 5.9 volt battery either isn't taking a charge or it's shot. While I have two 6 volt batteries I don't have any experience dealing with one single battery, normally I would isolate it, try to charge it separately and then load test it, but I'm not sure how to do that with a 6V but your going to have to get that figured out.

The other issue is that you clearly have a wiring problem somewhere that is causing the overheating of the wires, and I doubt that it is the power board as that is fused. In my 2005 2720 the battery cable runs under the trailer and into the space behind the fridge and is there wire nutted into the battery break away cable. From there it runs under the floor and into the power center space behind the tub. You're going to have to find, isolate, and test all of these wires, ground wires included. A systematic testing with a multimeter, looking for shorts to ground, should give you some actionable information.

Surely someone else will chime in here with other ideas but that is how I would approach this problem. Good luck.

 

[Bill]

The fact that you are seeing 12.7 volts at the battery pair says that the batteries are properly joined with a plus-of-one-to-minus-of-the-other wire that puts them in series. The fact that one battery reads 6.7 volts, and you are seeing 6.7 volts at the power center (what a coincidence!) says to me that somehow the main black wire to the power center is connected to the join between the batteries, or the main white wire to ground is connected to the join between the batteries.

Please review all the connections to the batteries. Specifically, you should see a single wire connecting the positive pole of one battery to the negative pole of the other battery. There should be no other connections to either of these poles. I'm thinking that you may find one.

Check it and let us know. A photo showing the pair of batteries and all the wires connected to them would help. BTW, do you have an electric tongue jack?

Bill

 

[AngliaUSA]

HI Bill - thanx for the reply - yes I have an electric tongue jack - 2 wire and one wire is grounded to the frame of the tongue - the other to the black load side of the battery - I have double checked all my battery connections and I am pretty familiar with what goes where and why ... sorry no pics as the rig is at my other property in storage - i'll be up there next week to deal with the electrical - I wanted to arm myself with some expert forum knowledge prior to tearing into it ... probably time to upgrade my main battery wiring as well as my load center control board as I am considering Li batteries and adding a couple of solar panels to bring my Trail manor into the 21st century .. LOL - I'll report back with better pics next week - cheers

 

[Bill]

I am considering Li batteries and adding a couple of solar panels to bring my Trail manor into the 21st century

I would resolve the current issue before starting to modify the electrical system. Troubleshooting gets a lot more complicated when you add more variables.

Since your TM is not new, I assume it has not always had this problem. That begs the question - what has been done to the TM recently that could affect the wiring? It might not be something electrical. For example, maybe you replaced a stabilizer jack, and a nearby wire got abraded. Or maybe the wire to the tongue jack got pinched last time you folded or unfolded the tongue. (Does the jack have its own in-line fuse? It should.) Was an any work done inside the refrig compartment? That kind of thing. In other words, what has recently changed?

Keep us posted.

Bill

 

[rickst29]

Your photo of the 12V fuse board (IMG_0299) shows 2 wires in parallel on the "Battery +" connector. There should be only one, and it should be read 12V (not "around 6V"). The other lead might have been wired at the factory "OEM" to connect the bargman Tow Vehicle "battery charge", saving one of the smaller fused links - but that really should not have been done that way.

Somewhere inside the TM, there needs to be a 15A limiting fuse (20A is the absolute maximum size) for that wire. In my own 2619 - also from 2006, but built much later in the the TM factory had switched from the earlier Parallax power center to a WFCO box, the fuse panel in the WFCO had room for more ports. Your older Parallax has room for only six, and there are other "issues" inside the fuse board. You should replace at leas the fuse board. The Parallaxl converter board (for 120-VAC to 12 Volts DC) also tended to overcharge lead acid batte4ries pretty quickly, so you might consider replacing the entire Parallax - replacing the 120-VAC breakers and power distribution, the 120-VAC to 12V main converter baord, AND the "12V fuse board" all at once. I'd recommend a PD replacement for all of it, though you could go with separate parts as well. (The Converter needs to be lithium capable.)

When you disconnect the two "battery" wire ends at the fuse board, what are the readings on those two wires? If one reads zero, please also check tagain after plugging the bargman cable into your Tow Vehicle. (Turn on the TV, measuring while it runs at idle speed.) That "zero" bare end might read 12-13 volts after connecting the bargman cable.

 

[AngliaUSA]

(Battery problem update) I am guessing that I had a bad or 2 bad batteries that were somehow trying to equalize each other and shorting and causing the heat ? 'I think' I fixed it - by equalizing and charging (individually) with fresh battery acid and distilled water. Each battery now charges and holds at 6.8v respectively - I have double checked all the wiring to the main panel and can find no short, break or damage. Wires are properly connected - the in line '30amp load fuse' is good at the batteries and I am getting a combined 13.6v at the batteries and the same voltage at the main load panel battery input. A couple of pics attached - the main thing is that the VERY hot almost smoking battery wires have disappeared and seem to be handling the current just fine now - not even warm to the touch. The batteries are about 1 year old 6v Interstate/Powerfast Lead Acid Golf Cart deep cycle batteries. The large gauge bare copper wire is just a ground to the trailer tongue frame from the battery negative terminal. Not sure if it's required or needed but it's been there since I bought the trailer 10 years ago. I do have a 2 wire electric tongue jack - that also gets connected to the + terminal on the 12v side and the other wire to a frame ground connection.

This summer I plan on updating my main load panel , adding solar panels to the rear shell and LI battery's to my front battery boxes. But there seem to be a bunch of you that have done this electrics modernization so I'll do my research and due diligence on this most excellent forum before I buy anything and start updating - thanx in advance. James

 

[Bill]

I do have a 2 wire electric tongue jack - that also gets connected to the + terminal on the 12v side and the other wire to a frame ground connection.

If that 12-volt wire goes directly to Battery +, it must be separately fused. Less important, the jack's ground wire should be bridged across the hinge of the swing tongue.

Bill

 

[AngliaUSA]

Good point - I am pretty sure it already has a resettable fuse 'in line' but I'll add an in line fuse on the + wire of the trailer jack wiring if not. Cheers -

 

[rickst29]

The battery shown lower down within IMG_0391 is the "first" battery in your series pair, and you have a large black wire accomplishing the interconnect (from "+" on the lower battery into "-" on the upper battery).

Your bare "grounding bond" wire is the negative return wire for everything whch is powered by the TM main panel. (Under the bathtub wall, all the 12V grounding "white wires" are interconnected with the frame, using a pair of wires within a water-resistant box behind the street-side drain connectors.) The frame itself carries current forward to the "grounding" lug, and that wire connects the "-" terminal on the first battery. Everything in the TM which uses "12v" through the main panel depends on that wire, in order to get back to the battery.

But your grounding bond is a solid wire of bare copper, and the end is apparently wrapped around the terminal post without using a lug. In addition to suffering a lot of surface corrosion over the years, the naked wire is not flexible. I recommend that you replace this wire with a stranded segment (for more flexibility), with white insulation. Use a proper lug (tinned copper) on the end underneath the battery post.

Over the short distance from the frame mounted connector, AWG-8 is adequate. The insulation should be white. If you don't have a hammer crimper to attach your new wire end into the lug, you can buy a nice "battery cable" with one or two lugs already attached (and crimped, and soldered) on Internet at low cost - but be aware of that many of the the "battery cables" being offered for sale are much larger than AWG-8, and probably can't fit into the TM'S orginal (OEM) frame-mounted wire connector.

If that connector is loose (versus the frame) or corroded, you will need to tighten or replace it. Some galvanic corrosion occurs between the copper wire connector and the underlying steel frame over time, the two surfaces might also need to be cleaned or replaced with a "tinned" connector.

- - -
There is a larger white wire underneath the lower battery, is that connected to your frame post? And also - if your tongue jack wire is the tiny white one underneath the lower battery terminal, it might benefit by upgrading to a large wire size.

 

[Wavery]

(Battery problem update) I am guessing that I had a bad or 2 bad batteries that were somehow trying to equalize each other and shorting and causing the heat ? 'I think' I fixed it - by equalizing and charging (individually) with fresh battery acid and distilled water. Each battery now charges and holds at 6.8v respectively - I have double checked all the wiring to the main panel and can find no short, break or damage. Wires are properly connected - the in line '30amp load fuse' is good at the batteries and I am getting a combined 13.6v at the batteries and the same voltage at the main load panel battery input. A couple of pics attached - the main thing is that the VERY hot almost smoking battery wires have disappeared and seem to be handling the current just fine now - not even warm to the touch. The batteries are about 1 year old 6v Interstate/Powerfast Lead Acid Golf Cart deep cycle batteries. The large gauge bare copper wire is just a ground to the trailer tongue frame from the battery negative terminal. Not sure if it's required or needed but it's been there since I bought the trailer 10 years ago. I do have a 2 wire electric tongue jack - that also gets connected to the + terminal on the 12v side and the other wire to a frame ground connection.

This summer I plan on updating my main load panel , adding solar panels to the rear shell and LI battery's to my front battery boxes. But there seem to be a bunch of you that have done this electrics modernization so I'll do my research and due diligence on this most excellent forum before I buy anything and start updating - thanx in advance. James

 

[Wavery]

Just one quick question........ Are you doing all this testing with the 110V power cord plugged in to house current?

 

[AngliaUSA]

Thank you all for the observations and comments/recommendations - I very much appreciate the advice - which I shall follow. Batteries are tested without shore power / and that white cable is just a battery handle / carry cable to lift them in and out.