Lights in my Scamp pulse

[Scruffy]

Hi All,
I've been lurking on this forum for a while but this is my first post.

I'm thrilled with my 2000 Scamp 16 that I bought about 6 months ago. I've been through several minor fixes but this problem has me stumped. I don't know much about electrical so I'm not sure if this is a problem or just a quirk.

When I'm hooked to shore power my interior lights pulsate. They put out pretty good light but every three or four seconds they get slightly brighter then dim again.

I know it's not my imagination and I've already checked for poltergeist (just kidding )
Does anyone have any pointers/ideas?

Thanks in advance for any guidance.

[mszabo]

How do they react when it's not pluged in?
How old is you battery?
Try the lights without the battery hooked up on shore power.
Check all connections, make sure they are tight.
Test your voltage on the battery, on and off shore power.
Let us know what you might find.

[C&G in FL]

Do you get multiple lights pulsating when more than one is turned on? Are they incandescent or LED?
If LED, they can be touchy and will "flicker." If the answer to the first question is no, and you are using LED bulbs, clean the contacts with a pencil eraser.


Sent from my iPhone using Fiberglass RV

[Byron Kinnaman]

Been there done that.. The light are pulsing as the converter goes from charging the battery to not charging the battery. Find the breaker for the converter and turn if off and pulsing go away.

[Paul O.]

I had this happen not long ago and attributed it to the converter overheating. I had some stuff in a large plastic bag in the compartment under the dinette seat, and it shifted while traveling, or I placed it badly and it restricted the cooling air flow. The Scamp manual is very explicit about avoiding any converter air flow restriction. This means in front of its grille, as well as on the inside of the cabinet where the cooling fan is mounted. The red LED on the front of the American Enterprises CS2000XL indicated a flaw, but then it went off when I fixed the problem.

[Scruffy]

Sorry for taking so long to reply and thanks for all your input.

It looks like Byron put me on the right track. When hooked to shore power the pulse goes away when I turn off the circuit breaker on the power converter.


I guess that means that it is something that I just need to live with or turn off the circuit breaker when I'm only using the 12 volt (which is most of the time).

I notice When I disconnect the battery but stay connected to shore power the lights don't come all the way on they just give a slight intermittent glow in a pattern similar to the pulse, the water pump doesn't work at all. Is this normal meaning that if you wanted to remove the battery and use shore power only, there is a wiring change that would need to be done? Just hypothetical, l don't have any plans to do it.


My converter doesn't seem to have any status lights but all of my fuses seem to be good and my circuit breakers are all on. The battery 6 months old.




Thanks again for everyone's advice. This is a great website!

[Raspy]

Chargers have different strategies to accomplish the same thing, but most modern ones need a battery connected in order to determine what the charge level is. Smart chargers can't charge at all unless the battery has a minimum charge level to sense.

Yours is probably confused because it sees a load, but no voltage from a connected battery, when the battery is disconnected.

Older, simpler converters will carry a load with no battery, but still can act erratically when voltage varies and they immediately stop if disconnected because there is no battery to carry any load at all.

Chargers or converters can overheat if there is a big load in the system. This is normal and can cause them to cycle their cooling fans or cycle the charging current on and off. It happens more easily in hot weather. It also can happen if the batteries are sulfated or discharged at the same time as there is a heavy load.

Try to always have a battery connected when plugged in. I think Byron has it right that the charger is pulsing on and off either because the battery is showing fully charged or because the charger is overheating. Strangely enough, some earlier, not "smart" chargers, will pulse this way if connected with reversed polarity.

Check the polarity of the charger leads, always have a good battery in the circuit when hooked to shore power, make sure the charger is not overheating. Then just put up with it's design character as needed. It may be hard to determine if the charger is overheating, but if the weather is hot and the load is high, it will probably respond with some strategy to protect itself. Then later work just fine.

[gordon2]

Originally Posted by Scruffy

...

I notice When I disconnect the battery but stay connected to shore power the lights don't come all the way on they just give a slight intermittent glow in a pattern similar to the pulse, the water pump doesn't work at all. Is this normal [?]...

No, not normal.

Sounds like it very well could be a faulty converter.

What is the voltage on the 12 volt side when on shore power (and with no battery), with nothing on, with a few lights on, and with water pump on?

[Scruffy]

I'll double check my polarity and I need to get my hands on a volt meter.

It has been pretty hot here for the last couple months so I will dig into things further see how it responds over time.


Thanks again for everyone's input.

[Carol H]

Originally Posted by Scruffy

I'll double check my polarity and I need to get my hands on a volt meter.

It has been pretty hot here for the last couple months so I will dig into things further see how it responds over time.


Thanks again for everyone's input.

With all the symptoms you have stated my guess is the converter will "respond over time" with "I am totally done"

[Scruffy]

Yes Carol, that's what I'm thinking and I'm already pricing them.

[steve dunham]

You could have a bad diode / capacitor in your converter's rectifier
You may have to look at your converters DC output with a scope and a volt meter.

[gordon2]

Originally Posted by Raspy

Chargers have different strategies to accomplish the same thing, but most modern ones need a battery connected in order to determine what the charge level is. Smart chargers can't charge at all unless the battery has a minimum charge level to sense....

It just dawned on me that perhaps the OP does have a charger and not a converter. Since his trailer is second hand there is not telling what mods have been done.

If I understand the terminology right (and rather simplified) a RV converter is both a 12 volt power source for on-board electrical items, and a battery charger. Two things in one. A converter will power your trailer's 12 volt stuff just fine, battery or no battery.

A charger on the other hand (at least a good one) is trying to figure of the state of charge of the connected battery, and apply the appropriate voltage and current. If there is no battery, then the varying load as your turn things on and off will really mess with its little computerized brain.

So check and see what converter or charger you have... post the make and model number.

[gordon2]

Originally Posted by steve dunham

You could have a bad diode / capacitor in your converter's rectifier
You may have to look at your converters DC output with a scope and a volt meter.

He does not even own a $4 multi-meter and you want him to check the output with a $400 oscilloscope?

Might be cheaper to just replace the converter on the gamble that it solves the problem.

[steve dunham]

Originally Posted by gordon2

He does not even own a $4 multi-meter and you want him to check the output with a $400 oscilloscope?

Might be cheaper to just replace the converter on the gamble that it solves the problem.

If your want to play at being an electrician then you need to dress the part. If the OP doesn't own or know how to use a meter than replacing the converter is probably above his pay grade.

[Carol H]

Originally Posted by Scruffy

Yes Carol, that's what I'm thinking and I'm already pricing them.

The PD-4045 Power center is a popular replacement for the original Scamp converters.

[gordon2]

Originally Posted by steve dunham

If your want to play at being an electrician then you need to dress the part. If the OP doesn't own or know how to use a meter than replacing the converter is probably above his pay grade.

Well if your point is that its best to get someone more expert to help out in person, then you might be right.

But a typical converter has a 120 volt AC connection (often just a plug like about everything in your home), and two other connections for the 12 volts DC. Yes, you need to match positive and negative on the DC side.. but that is light years easier than learning to use an oscilloscope.