Converter problems

[Pat C]

The last weekend out with our trailer we had some kind of a power surge.All the light bulbs overheated to the point of melting the cover on the outside light.The fuse in the pump blew and the fantastic fan completely stoped functioning......Took the unit in to our RV shop and can not get a satisfactory answer as to why this happened.They had installed the converter aprox.a month ago.The first one they installed (burned up,their explanation) as soon as it was connected....They replaced it with another unit,same model.This time they are saying a fuse to the battery connection failed to blow and this caused the power surge??????They are going to replace the converter with another one(same model).I am afraid this will occour again and we will not just have melted light coverings but a melted trailer.Any suggestions as to what could have caused this problem....Thanks,Pat.

[Darwin Maring]

Problems in production run in batches so if the 2 bad units were in the same production run, it is feasable that another one of the same model may have a defect also so take a credit on the present converter towards a diferent model converter.

Ask for a replacement of the runed fan and other items. Do it in writing and when they refuse write to Good Sam Highways Magazine for help. They have great success in resolving these issues when you get the runaround. Not a Good Sam mamber?

[Dean & Mary]

Pat, More information please.

Were you connected to shore power? Your symptoms certainly indicate that you were, but you made comment about battery fuse. If connected to shore power, was it at home, campsite or... ?

Dean

[Pat C]

Pat, More information please.

Were you connected to shore power? Your symptoms certainly indicate that you were, but you made comment about battery fuse. If connected to shore power, was it at home, campsite or... ?

Dean

Yes we were connected to shore power,at home at the time I first noticed a problem.That is why I do not understand why the fuse for the battery would come into play.I really do not understand how the converter works,except that it converts the 12 vot system to run off 110.I am tending to think that the people that installed the converter have not wired it correctly.

[Ed Harris]

Converters seem to range in design from a mere 12vdc transformer to convert 120vac to 12vdc all the way tosophisticated regulated power supplies with multi-stage battery chargers built-in.

Without more specific information about your setup it will be difficult to have even a vague idea what maty be happening.

If your battery is being charged by the converter then there is certainly reason for it to be "in the loop" here.

I do not understand the design behind some converters ,like the one in my Scamp that somehow attempts to charge the battery although it appears to be just connected as another load to the converter.
I can not understand that this will work or be any good for the battery at all.
Either it will never charge the Battery,over charge it or if the battery develops a problem it then can become a bad load on the converter potentially causing problems like you describe above.

The claim that the battery fuse didn't blow sounds like total B.S. to me.
If there is too much current being drawn by the battery and there is a standard fuse of any kind,it will blow. They are not real sophisticated devices prone to failure.
If the correct size fuse was in there,they blow.

Anyway.please try to be a little more specific as to the setup and maybe it will be more clear what may be going on.

Either way I am doubtful that I would trust the people already working on it,they do not sound too bright or pro-active to me.

Ed

[Pete Dumbleton]

I do not understand the design behind some converters ,like the one in my Scamp that somehow attempts to charge the battery although it appears to be just connected as another load to the converter.
I can not understand that this will work or be any good for the battery at all.
Either it will never charge the Battery,over charge it or if the battery develops a problem it then can become a bad load on the converter potentially causing problems like you describe above.

That's exactly how non-mutistage converters ruin batteries by being connected to them for too long (like during storage, not just the weekend). It just puts out a steady voltage at an amperage the battery will accept up to its rated output.

[Morgan]

The last weekend out with our trailer we had some kind of a power surge.All the light bulbs overheated to the point of melting the cover on the outside light.The fuse in the pump blew and the fantastic fan completely stoped functioning......Took the unit in to our RV shop and can not get a satisfactory answer as to why this happened.They had installed the converter aprox.a month ago.The first one they installed (burned up,their explanation) as soon as it was connected....They replaced it with another unit,same model.This time they are saying a fuse to the battery connection failed to blow and this caused the power surge??????They are going to replace the converter with another one(same model).I am afraid this will occour again and we will not just have melted light coverings but a melted trailer.Any suggestions as to what could have caused this problem....Thanks,Pat.

Pat,

There were at least two problems involved: the converter malfunctioned and caused the surge, the fuse on the lighting circuit was not sized properly (too big a fuse) and failed to protect that circuit. The water pump fuse did its job.

You did not say what brand and model the converter is, but its voltage regulator section apparently failed. Blaming that on the failure of the battery fuse to blow is just ignorant. They may as well blame the lighting fuse.

Did you have this work done at Bubba's Bait Shop and RV Repair?

[Dean & Mary]

Where to begin:

Ed you must have meant 120vac to 12vac. Transformers only convert AC to AC. The AC has to be rectified to produce a DC voltage. I may have taken your comment to literal and you meant "mere 12vdc power supplies". If so, sorry.

The problem is: Unacceptably high DC voltage on the output. You may want to consider the following:

1) Check shore line power for proper polarity and grounding.

2) If you purchased this converter new, you should have received an owner's manual and an installation manual. Verify the proper installation of the unit paying close attention to all the connections including how the unit is grounded.

3) Check converter's output voltage before connecting loads. This is to protect your loads; a bad load will not cause voltage to rise to unacceptable levels.

4) Find someone else to install your converter. There was either a communication error when installer referenced battery fuse or he doesn't have a clue.

5) It's possible, but unlikely that you got multi bad converters. What brand are you installing?

[Pat C]

Where to begin:

Ed you must have meant 120vac to 12vac. Transformers only convert AC to AC. The AC has to be rectified to produce a DC voltage. I may have taken your comment to literal and you meant "mere 12vdc power supplies". If so, sorry.

The problem is: [b]Unacceptably high DC voltage on the output. You may want to consider the following:

1) Check shore line power for proper polarity and grounding.

2) If you purchased this converter new, you should have received an owner's manual and an installation manual. Verify the proper installation of the unit paying close attention to all the connections including how the unit is grounded.

3) Check converter's output voltage before connecting loads. This is to protect your loads; a bad load will not cause voltage to rise to unacceptable levels.

4) Find someone else to install your converter. There was either a communication error when installer referenced battery fuse or he doesn't have a clue.

5) It's possible, but unlikely that you got multi bad converters. What brand are you installing?

The Converter in a Parallax series 6700.I relied completely on the RV techs advice on what size/type of Converter was needed in my Boler.Although he is trying to blame a fuse that did not function properly I have doubts and wonder if it is not the function of the converter to control the amount of power being supplied.One section of this units spec state "If the 12 volt load exceeds the converters output rating the output voltage will DROP to prevent any further increase in power.?????Evidently NOT.Because we live in an area where we have one RV shop within hundreds of miles I really did not have much choice as to where I would have any work done.I am doubting the ability of this facility.They know I do not know much about the electrical system and probably think they can tell me whatever and I will believe them.....

[Dean & Mary]

He is trying to blame a fuse that did not function properly

Yes, fuses often don't function properly ... NOT

The battery fuse to which he is referring isn't even in the circuit that malfunctioned. I have to assume you don't have two 12 volt batteries wired in series or your TV doesn't have a malfuntioning alternating.

The Parallax 6700 series is a good converter. You probably have the 6730, a 30 amp converter. That converter should work just fine and should have the fuses necessary to prevent major problems. If your light cover melted, then the voltage was held at a high level for a significant amount of time. We are not talking surge.

[Darwin Maring]

It's time to go to the source

http://www.parallaxpower.com/.

[Dan Meyer]

It sounds like your converter failed like my original converter failed - it put out too much voltage. I replaced the original MagnaTek 6720 with a Parallax Power 6730 last February. It too has failed, but it barely puts out any power. I'm thinking that I should just throw away the 120vac to 12vdc converter section, and wire in a good outboard battery charger instead.

More as it develops.

-- Dan Meyer

[Pat C]

It sounds like your converter failed like my original converter failed - it put out too much voltage. I replaced the original MagnaTek 6720 with a Parallax Power 6730 last February. It too has failed, but it barely puts out any power. I'm thinking that I should just throw away the 120vac to 12vdc converter section, and wire in a good outboard battery charger instead.

More as it develops.

-- Dan Meyer

This converter was only installed one month ago and what really concerns me is that the first attempt to install one failled now the second one is kaput.I worry that it is the person installing these converters not the converter itself.However he insists that he has installed many converters and this is the first time anything like this has happened.Now if he installs another converter the trailer will be stored until spring so it will be months before I know if we will have the same problem crop up when we use it.I have had two trilliums,neither one had a converter just 110.Worked perfectly for us as we usually have full hookup when we camp.Only problem we would not be able to keep our fantastic vent if we had no twelve volt.

[Dan Meyer]

It sounds like your converter failed like my original converter failed - it put out too much voltage. I replaced the original MagnaTek 6720 with a Parallax Power 6730 last February. It too has failed, but it barely puts out any power. I'm thinking that I should just throw away the 120vac to 12vdc converter section, and wire in a good outboard battery charger instead.

More as it develops.

-- Dan Meyer

I took my converter out this evening, and took it apart to get at the circuit board. The only thing that looks bad is a 25 volt 2500 uF capacitor that is across the output leads of the converter. I'll find a suitable replacement and intstall it - but I have some trouble believeing that this is the problem. This may take some time to find parts, so don't look for an update before the weekend.

-- Dan Meyer

[Paul from NWOnt]

This converter was only installed one month ago and what really concerns me is that the first attempt to install one failled now the second one is kaput.I worry that it is the person installing these converters not the converter itself.However he insists that he has installed many converters and this is the first time anything like this has happened.Now if he installs another converter the trailer will be stored until spring so it will be months before I know if we will have the same problem crop up when we use it.I have had two trilliums,neither one had a converter just 110.Worked perfectly for us as we usually have full hookup when we camp.Only problem we would not be able to keep our fantastic vent if we had no twelve volt.

I would say that you could keep your fantastic fan by merely using a regulated power supply (basically an A/C adapter that will handle the load) to power just the fan, and running the rest of the trailer on A/C.

If you decide to install another converter, then just run it for the weekend, or even a week before putting the trailer into storage.

The more posts I read about bad converters, the more I want to do the "smart charger" mod.

[Darwin Maring]

Should the DC side of the converter be connected backward to the battery, what effect would that have to the 12VDC?

[Dean & Mary]

I took my converter out this evening, and took it apart to get at the circuit board. The only thing that looks bad is a 25 volt 2500 uF capacitor that is across the output leads of the converter. I'll find a suitable replacement and intstall it - but I have some trouble believeing that this is the problem. This may take some time to find parts, so don't look for an update before the weekend.

-- Dan Meyer

Dan,

Capacitors sometimes fail by becoming “leaky” if you will. They no longer are just a capacitive reaction in a circuit, but develop an internal resistance. The capacitor then leaks current from supply to ground, reducing the overall potential of the supply voltage. If this is the case, it could be causing your power loss. Capacitors also fail by opening up and providing no capacitance in a circuit. Both of these conditions can easily be tested with a meter. You could simply remove it and test your converter without it or better, check the internal resistance of the capacitor after it is removed with a voltmeter.

Pat, You might want to consider spending a little more and get a Xantrex converter with 3 stage charging. I would have to assume they are replacing your failed converters under warranty.

Dean

[Dean & Mary]

Should the DC side of the converter be connected backward to the battery, what effect would that have to the 12VDC?

[b]Poof !

[Orlen Wolf]

Should the DC side of the converter be connected backward to the battery, what effect would that have to the 12VDC?

I'm assuming you mean a reverse polarity connection to the battery. Batteries get very mad if you mix up their +s and -s.

The converters I have seen have a fuse in the line to the battery and a reverse polarity protection diode. If you connect the battery backwards it will open the fuse and disconnect the battery. Depending on the level of sophistication of your converter's protection circuits it could also damage the converter. Unfortunately many converters are very unsophisticated.

Also, unsophisticated converters don't work well when there is no battery connected to buffer the converter output. Without the battery the output voltage rises quite a bit. This could be the reason your lights got so bright and melted the covers.

If it was me I would find another RV repair place, even if means a long drive. I really doubt the competency of the facility doing the work.

Someone recently posted a link on this forum to a web page entitled "The 12Volt Side of Life" that had a lot of good information on 12V RV systems. I think it could answer a lot of your questions. If I remember right it was about 20 pages long and very detailed. Sorry I don't have the time now to do a search.

[Al V]

on a lighter note the parallaxpower 7300 (newer casitas) can be run on shore power with the battery removed or isolated, this is from their tech support