Strange Electrical Issue

[cswinford]

Thanks in advance to anyone that helps us solve this mystery.

We were in St Louis yesterday and left for Kansas which means we were on the road for about 9 hours. I tell you this simply to say that my battery did charge during that drive time. I'll also say that we haven't experienced any electrical issues up to this point.

We arrived in Kansas last night and plugged into 30 amp shore power. We noticed the interior lights were very dim but didn't think too much of it.

I woke up this morning and started noticing electrical issues, such as the refrigerator was off and would try to start but couldn't. The furnace would try to start but couldn't. The water heater would try to light but couldn't. The built in stereo would try to come on but just flickered off/on. It seemed that everything on the 12 volt side was having issues; as if it wasn't getting enough amperage. I shut down all the interior lights and was able to get some stuff to come on but it was very limited.

This led me to believe that we had a bad battery because I knew it had plenty of charge from the drive the day before. The strange thing is that when I removed the battery altogether the 12 volt was operating perfectly. All lights were bright and everything worked as it should (I'm still plugged into shore power at this point).

I took the battery to a local Advanced Auto and they checked it. Surprisingly to me, they told me the battery was just fine.

So now I'm scratching my head. Do I have a bad converter? What else could it be?

Thanks!
Chad
http://longlongwaytotipperary.com

[cswinford]

Me Again wrote:

cswinford wrote:

JamesBr wrote:
I would also say check to see while under this load how hot the converter is getting and if the fan is turning on. I have helped a couple of friends now replace the fan on their converter because after only a few years the fan bearing had siezed up and the converter would shut down for thermal protection.


Once we sourced the proper computer fan (size and voltage) and replace it, none of them have had any issues with the converter.

That's interesting... because honestly, I have never once in the 18 months we've owned this unit heard a fan come on in the converter. Not once...and we lived in the unit for 14 straight months while traveling. I have never messed with the converter so I hadn't expected to hear a fan. I'll look into this.

So it was not the brakes??? Chris

Nope, not the brakes. Thanks for the suggestion, though!

[Me_Again]

cswinford wrote:

JamesBr wrote:
I would also say check to see while under this load how hot the converter is getting and if the fan is turning on. I have helped a couple of friends now replace the fan on their converter because after only a few years the fan bearing had siezed up and the converter would shut down for thermal protection.


Once we sourced the proper computer fan (size and voltage) and replace it, none of them have had any issues with the converter.

That's interesting... because honestly, I have never once in the 18 months we've owned this unit heard a fan come on in the converter. Not once...and we lived in the unit for 14 straight months while traveling. I have never messed with the converter so I hadn't expected to hear a fan. I'll look into this.

So it was not the brakes??? Chris

[cswinford]

JamesBr wrote:
I would also say check to see while under this load how hot the converter is getting and if the fan is turning on. I have helped a couple of friends now replace the fan on their converter because after only a few years the fan bearing had siezed up and the converter would shut down for thermal protection.


Once we sourced the proper computer fan (size and voltage) and replace it, none of them have had any issues with the converter.

That's interesting... because honestly, I have never once in the 18 months we've owned this unit heard a fan come on in the converter. Not once...and we lived in the unit for 14 straight months while traveling. I have never messed with the converter so I hadn't expected to hear a fan. I'll look into this.

[JamesBr]

I would also say check to see while under this load how hot the converter is getting and if the fan is turning on. I have helped a couple of friends now replace the fan on their converter because after only a few years the fan bearing had siezed up and the converter would shut down for thermal protection.


Once we sourced the proper computer fan (size and voltage) and replace it, none of them have had any issues with the converter.

[Me_Again]

You didn't happen to pull out the emergency brake cable did you????? That puts a large load on the system with the electric brakes activated. That would match the conditions you describe! Do you get a fairly large arch when connecting the battery cables???

Plug the little black plastic "thingy" back in!!!!!! And report back!! Maybe I get today's prize!!!

Chris

[Allworth]

First problem: Dim lights=low voltage on the 12volt side.

Did they do a deep draw down load test on the battery? Sounds like a bad cell. It should show about 13.6 volts under no-load conditions. 12.5 volts is low. That could be a surface charge that is killed as soon as you put a load on it. A bad (partially shorted) cell will make it impossible for the converter to charge the battery.

Second problem: Lights cutting out on shore power.

The thermal protection on the converter is kicking out. Was the battery connected when this happened? ((ON EDIT: I see that it was disconnected. That makes it tougher but it still sounds like thermal overload.)) The converter should be able to carry the entire 12volt load when on shore power, but if the above condition (bad cell) exists, the battery may be pulling so much current trying to charge that the converter can't keep up.

Electrical problems can drive you batty. Good luck.

[LostinAZ]

cswinford wrote:
Here's an update.

After running for a few hours with the battery completely unhooked and running many of the interior 12 volt lights, all of the sudden all the 12v lights went off. We shut them off, waited a bit, and then turned them back on with no problem. Then the same thing happened again later.

I think the issue is definitely with the converter but maybe its a loose wire or something when it heats up under load.

A couple of people thought it might be the battery not charging but the battery tested at 12.5v, so I don't think that's the issue.

Thanks to all who have replied thus far.

Be careful with the conclusion you may be drawing with the converter only running the lights. The converter tries to put out a higher voltage 13.xx plus Volts to charge the battery. That type of voltage on the lights and any other 12V devices may be putting an overload on the converter and it may be thermally shutting down temporarily. I'm not sure it is a good thing to run all the 12V accessories with no battery installed for a long period of time. I still suspect either wiring or whether the battery is good or not. The way to find out if the converter is charging the battery or not is to check the voltage on the battery when it is installed and you are hooked up to shore power. The reading on the battery should read 13.xx plus volts. If it isn't the converter has either shut down or there is a loose connection somewhere. It might even start out at 13.xx plus volts and then shut down like it is with no battery installed and running the lights. That will be an indication that the converter may be weak. if it starts out at 13.xx plus volts let it alone for a couple of hours and then check the voltage again. If it is 13.xx plus volts it is still charging the battery, if it is back to 12.5 V the battery may be charged or the converter has shut down. If it never gets to 13.xx plus volts than there is a wire connection problem.I still don't rule out a battery problem if it hasn't been tested under load. A battery can test good with a VOM because there is a very, very small load (micro-amps) put on the battery testing it. However, if the internal resistance of the battery has gotten too high whenever there is a large load put on it like your lights the voltage will drop significantly. Usually when testing a battery properly a 100 AMP or larger load is put on it temporarily.

[TucsonJim]

Artum Snowbird wrote:
I had the same problem exactly. While I was running the truck, the battery would charge, but on shore power it would not.

While plugged in to shore power find your 12 volt wires coming out of the converter and touch them with your finger. Wiggle them and see if the lights suddenly turn bright. In my case, the white wire coming out of the converter was quite hot, the lights flashed when I wiggled the wire up to bright.

It was totally a loose wire connection and nothing else. Sure changing the converter would fix it, because the wires are removed and then replaced and tightened. But all I needed was a screwdriver to fix mine.

That is why you put the meter leads on the 12V output leads of the converter when you're trouble-shooting. It takes the wires out of the equation if you're checking for converter power.

[cswinford]

Here's an update.

After running for a few hours with the battery completely unhooked and running many of the interior 12 volt lights, all of the sudden all the 12v lights went off. We shut them off, waited a bit, and then turned them back on with no problem. Then the same thing happened again later.

I think the issue is definitely with the converter but maybe its a loose wire or something when it heats up under load.

A couple of people thought it might be the battery not charging but the battery tested at 12.5v, so I don't think that's the issue.

Thanks to all who have replied thus far.

[MrVan]

Artum Snowbird wrote:
I had the same problem exactly. While I was running the truck, the battery would charge, but on shore power it would not.

While plugged in to shore power find your 12 volt wires coming out of the converter and touch them with your finger. Wiggle them and see if the lights suddenly turn bright. In my case, the white wire coming out of the converter was quite hot, the lights flashed when I wiggled the wire up to bright.

It was totally a loose wire connection and nothing else. Sure changing the converter would fix it, because the wires are removed and then replaced and tightened. But all I needed was a screwdriver to fix mine.

This is more likely.

[Artum_Snowbird]

I had the same problem exactly. While I was running the truck, the battery would charge, but on shore power it would not.

While plugged in to shore power find your 12 volt wires coming out of the converter and touch them with your finger. Wiggle them and see if the lights suddenly turn bright. In my case, the white wire coming out of the converter was quite hot, the lights flashed when I wiggled the wire up to bright.

It was totally a loose wire connection and nothing else. Sure changing the converter would fix it, because the wires are removed and then replaced and tightened. But all I needed was a screwdriver to fix mine.

[enblethen]

What happens when the rig is plugged into the TV?
Does the lights get brighter with TV engine running?

[TucsonJim]

MrVan wrote:
With the symptoms you have described I think you can rule out a blown fuse on the output side of the battery. My guess would be is the battery is not being charged properly by the converter or the battery is failing under high current demand. Since everything seems to work good when you disconnect the battery that would indicate to me that the converter is working properly. When the battery was checked did they check it under load?

If the DC lights and appliances work ok when the battery is not connected that seems to indicate the converter is doing its job but somehow that charge from the converter is not getting to the battery or the battery is bad. I see no reason to replace the converter if it will run the dc stuff without the battery.

Somehow I missed the part about it working when the battery was disconnected. Back to the drawing board.

[MrVan]

With the symptoms you have described I think you can rule out a blown fuse on the output side of the battery. My guess would be is the battery is not being charged properly by the converter or the battery is failing under high current demand. Since everything seems to work good when you disconnect the battery that would indicate to me that the converter is working properly. When the battery was checked did they check it under load?

If the DC lights and appliances work ok when the battery is not connected that seems to indicate the converter is doing its job but somehow that charge from the converter is not getting to the battery or the battery is bad. I see no reason to replace the converter if it will run the dc stuff without the battery.

[TucsonJim]

These are the exact symptoms of a bad converter. Here's a simple troubleshooting procedure:

1. Disconnect from AC Shore power or shut your generator off.
2. Disconnect the negative battery terminal.
3. Open the converter housing and pull the converter out.
4. There should be one or two fuses near the converter 12VDC side. Make sure they are good by checking them with your multi-meter. If you don't know how, let me know and I can give you instructions.
5. If the fuses are good, carefully reconnect to shore power and check the voltage at the 12VDC connection point on the converter with your meter (where the large wires are coming out). If your meter reads approximately zero volts, your converter is bad. Disconnect from the AC source and replace the converter.

If you have 13-14 VDC on the converter, then there is something else wrong in the circuit such as a bad fuse, a battery disconnect switch in the wrong position, a loose wire, bad battery, etc.