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wmb · 01-07-2021, 10:42 AM

Hi all, Happy New Year

Today we noticed a burning smell coming from the fuse box of our 2013 Flying Cloud 25'. Opening up the panel I can see that the battery neg terminal is charred so I flipped off the circuit to the converter. Went to check the batteries (Interstate SRM-24) and there's a lot of corrosion on the terminals and the main nut holding them in place. Water levels are lower than they normally are whenever I check - last check was a couple of months ago.

Any advice on replacing the converter and/or batteries? I feel this is something I could tackle myself. Should I have any other concerns about living temporarily with the converter breaker off?

BayouBiker · 01-07-2021, 11:19 AM

Not sure the batteries are bad, but they did get overcharged and "cooked" a bit. Clean off the corrosion with a lot of water, then add water, then use a bit of baking soda on the outside to neutralize any remaining acid. Then check the battery with a hydrometer if you have one.

On the battery cable, remove the connection, clean it with some sandpaper or a wire brush and reinstall tighten it to 45 inch lbs or very very tight with a screwdriver.

On the Converter, maybe it just got confused and overcharged the battery. Turn it on again and watch the battery voltage it should not be above 14.6 volts charging and then should drop to 13.2 when the battery is full. If it does not do this you may need to replace the converter but we can test a bit further.

tbrowne · 01-07-2021, 11:36 AM

Reading that the negative terminal is a bit charred is a major warning sign to me. If you have the original converter and the coach is a 2013 model, I'd consider replacing it just to be on the safe side. A quality after market converter will give better service and isn't a major expense. Batteries may be OK but I wouldn't trust the converter not to be a fire hazard down the road. If in doubt call one of the converter suppliers and see what they have to say.

BayouBiker · 01-07-2021, 11:49 AM

I rather suspect a poor negative connection. fuses and breakers protect the cables and connections from true overcurrents. The poor connection would also account for overcharging. I'd get the batteries in order, and clean the connection, then see if the converter was at fault.

Gene · 01-07-2021, 12:18 PM

How old are the batteries? Do you have a battery tester (hydrometer)? They are cheap to buy and will tell you if any cells are bad after you add water. Do you keep the trailer plugged in for months without using it? The OEM converter can cook the batteries if left plugged in for months. Replacing the converter can be done if you have some ability with wires and screwdrivers and such. If you have a FB, the space for your body to fit can be a challenge to get to the converter. And when you remove the wires from the OEM one, mark them with tape or write down the wire colors and what terminals they go to. It is really easy to get them wrong. The OEM one probably has a one stage converter—that means it doesn't go to trickle charge when the batteries are fully charged. It is best to have a three stage converter. There are better brands than used by Airstream.

There are many options with batteries. You probably have series 24 and can go up to the next series, but probably will have to modify the battery box a bit. Life Line batteries last a lot longer than the OEM ones, but are expensive. And some people use two golf cart (6 v.) batteries as they last longer and are also expensive. There are many battery options and some of the choice depends on whether you boondock a lot or sometimes or never.

It would be easier to answer if we knew how you use your trailer and what you want in terms of camping.

wmb · 01-07-2021, 02:50 PM

Thanks everyone for the great tips and observations. More info:

We're full-time in the Airstream and we've been stationary now for almost two years (we were just about to hit the road again when covid hit). When we travel we almost always stay at sites with at least electric hook ups. Only occasionally do we dry camp, and we have a small portable gas generator that's enough to power outlets for laptops, TV, etc.

Since it's our home we're more than happy to spend whatever it takes to get the right quality gear.

The batteries were installed by the previous owners in 2015. I've topped them up with distilled water and was surprised at how much I had to put in. Every time I've checked the levels the water had looked like it was about 3/4 of the way up to the top on each cell, and so I haven't been adding anything, thinking that since we're constantly on shore power and not really discharging them, that they were fine. Now I could see that one cell was very low and the rest around half-way up the tube, but when I started pouring, every cell took a lot to top up - altogether I used over half a gallon.

I'm attaching a picture of the battery terminals on the converter. We have a rear bed model and the converter is in next to the fridge. It's a Parallax 7355 model and it looks very easy to unscrew and slide out (assuming the wires are long enough behind there. I'm happy to replace it and I'm fairly comfortable with electrical work (I've installed new circuits, breakers, ceiling fans, etc. in my house). My only concern would be getting something that easily fits in the space without too much modification.

The only battery level meter I have in the Airstream is the red/amber/green LED in the tank level monitor, but I can break out the multimeter...

**GCinSC2** · 01-07-2021, 03:46 PM

That battery negative looks toasty!

Loose screw at one time? Resistance, heat, resistance, heat and repeat.

BayouBiker · 01-07-2021, 03:50 PM

So the negative connection overheating is almost surely due to a poor connection (edit: as GC says). You definitely want to take the wire out and clean it up as mentioned before. then watch it the next couple days to see if it warms up. You'll have to regenerate the batteries since they were so low on water. Let them charge and take a hydrometer reading for each cell and report back. I'm still not ready to say the converter/power supply is bad just yet. You will have to get out the multimeter. And order a hydrometer or pick one up at Walmart or an auto store.

dznf0g · 01-07-2021, 04:17 PM

Is it just me, or do those rivets, which I am presuming hold the lug to some conductor on the back, look not well seated?

wmb · 01-07-2021, 04:20 PM

Interestingly, the wire, screw and terminal are remarkably clean compared to the area around the two rivets on the converter. As I was unscrewing it I noticed that one of the strands looked like it may have been touching the circuit board or possibly the rivet (in the previous picture you can see the positive wire is almost doing the same thing). When I reconnected I made sure the strands were all inside the terminal.

After reconnecting the wire, battery and breaker the multimeter reads 13.6V (charging, I assume since it read ~10V while it was disconnected). I also don't think I can smell burning any more, although I could be going nose blind at this point...

BayouBiker · 01-07-2021, 04:23 PM

I'd say the heat degraded / vaporized a bit of the resin on the board. The rivets are structural to handle torque from the screw. If it warms up after clean up, it will need to be replaced.

Edit: That all sounds encouraging, wmb. 13.6 is not unexpected given the battery condition. It would have been nice to hear they were accepting 14.4 or so but they may not take much current for a bit. Hopefully they will come up to a reasonable state of charge eventually. Do you happen to have an automotive charger? If not, You may need to borrow one to recondition these batteries and you will need a hydrometer also.

Now would be a good time to check the screws on all the other neutral and ground wires.

dznf0g · 01-07-2021, 04:24 PM

What do the rivets fasten on the rear?

Gene · 01-07-2021, 04:34 PM

Quote:

Originally Posted by dznf0g

Is it just me, or do those rivets, which I am presuming hold the lug to some conductor on the back, look not well seated?

The upper one for battery negative looks loose since there seems to be shadow around or under it. If the other one isn't loose, it may be tight enough, but maybe not.

Five years service from a basic battery is pretty good. As I understand it, the water should cover all the cells—the water transmits the ions from one to cell to another and if the water is too low, less electricity. If everything works, maybe it is best, after tightening any contacts, to just monitor the batteries. So long as you are in one place, you don't really know how long they will last boon docking. They may test ok now, but not be so great boondocking. But, so long as you are stationary, you may be fine, but probably will need batteries once you travel.

There are many battery and converter threads and using the search function you will find a great deal of info on batteries and converters.

wmb · 01-07-2021, 11:25 PM

So, I monitored the temperature around the neg terminal for about 3 hours tonight and it was never above 75F. We left the ceiling fans venting and left for an hour or so and when we came back we could still smell burning, but the neg wire was not hot.

Out of an abundance of caution (and because we're currently dog-sitting in a neighbor's house so we had an alternative sleeping option), we decided to unhook shore power overnight.

Came back an hour later and the battery light was flashing red, multimeter reads 9.5V, so I reconnect shore power. After a few minutes I checked the temperature of the neg wire and it was over 200F with the case fans blowing full. I flipped off the breaker to the converter and waited for it to cool, then flipped it back on. This time the temperature has stayed down around 80F.

Is it struggling to charge the batteries now, hence the overheating?
Not sure if I should trust this converter now.
What are the downsides to running on shore power only with the batteries disconnected and the converter breaker open? The only issue I see is that the fridge seems to need a DC supply, even to run on propane?
Or should I just disconnect shore power and the batteries until I can get replacements?

dznf0g · 01-08-2021, 03:23 AM

Quote:

Originally Posted by wmb

So, I monitored the temperature around the neg terminal for about 3 hours tonight and it was never above 75F. We left the ceiling fans venting and left for an hour or so and when we came back we could still smell burning, but the neg wire was not hot.

Out of an abundance of caution (and because we're currently dog-sitting in a neighbor's house so we had an alternative sleeping option), we decided to unhook shore power overnight.

Came back an hour later and the battery light was flashing red, multimeter reads 9.5V, so I reconnect shore power. After a few minutes I checked the temperature of the neg wire and it was over 200F with the case fans blowing full. I flipped off the breaker to the converter and waited for it to cool, then flipped it back on. This time the temperature has stayed down around 80F.

Is it struggling to charge the batteries now, hence the overheating?
Not sure if I should trust this converter now.
What are the downsides to running on shore power only with the batteries disconnected and the converter breaker open? The only issue I see is that the fridge seems to need a DC supply, even to run on propane?
Or should I just disconnect shore power and the batteries until I can get replacements?

What's the charger output voltage when you get this 200* episode?

**GCinSC2** · 01-08-2021, 05:37 AM

wmb,

I was given one of those distribution boards and have it as a spare. I just pulled it and checked. That NEG terminal has a connection on the backside of the board. I used a meter and the NEG only connects to this other term on the back, it does not connect to any other point on my board, all the rest are for POS distribution.

Suggest you look on the backside for another wire connection. CAUTION if you insert a screwdriver to tighten it looks like a risk of contacting the adjacent POS term on the back as the screw on mine anyway faces UP.

If you need a pic of mine send me PM with contact info. I'm not able to post pic here.

On the top right of the board the part no. is 85A FH-7300-001

And this type connection might work as a temp bypass if the wire can be routed to use it. https://www.lowes.com/pd/Blackburn-0...Bolt/999922658

Gary

**richard5933** · 01-08-2021, 07:57 AM

Quote:

Originally Posted by wmb

...As I was unscrewing it I noticed that one of the strands looked like it may have been touching the circuit board or possibly the rivet...

I've found that on larger stranded wires like that it's helpful to use crimp-on ferrules. They're quite common in Europe, but not so much in the US. They make it much easier to maintain a tight connection and provide a better contact when using screw-down terminals. When done correctly, the strands become essentially a single unit which can be held down more securely without struggling to keep all the strands under the set screw.

The picture I've attached shows them used on my transfer switch, but I've also used them for the heavy-gauge wires going to my convert and solar charge controller.

I got the crimping tool and ferrules from Amazon for reasonable prices. The crimper comes in square and hex shapes for use in different types of terminals.

Not for everyone or in every situation, but useful nonetheless.

wmb · 01-08-2021, 08:39 AM

Quote:

Originally Posted by dznf0g

What's the charger output voltage when you get this 200* episode?

Damn, I didn't measure it. I've been testing the temperature every two hours and it's stayed around 80F. Now I have daylight I'm going to slide the unit out and take a look behind.

wmb · 01-08-2021, 08:52 AM

OK so it looks like the batteries aren't holding a charge. with the converter breaker closed I get 13.2V, when it's open it drops to 10.4V and continues to fall. How long should it take to fully charge?

BayouBiker · 01-08-2021, 08:53 AM

Well it sounds as if the batteries are in a bad way to have dropped so fast after three hours on a charge. At this point I would remove the batteries or at least charge them with an automotive charger to try to recover them.

Damage to the converter and power board sounds like result of the batteries going bad and shorting. Me? I'd resolve the battery issue first, get fully charged and functioning batteries in there first and then come back to the board.

I don't know how the others feel but I think if you can get to the back of the board, resoldering the connection may be an option. That it went above 90C while the wires didn't indicates the board connection is the weak link.