Converter issue?

[Glenn449]

Hello everyone, new to the forum here, but have been RVing for a while. Finally went full time 3 years ago. Decided to settle down for a year or 2 on an annual site after the pandemic hit. So we sold a bumper pull and bought an older 5th wheel. It's definitely had it's share of issues, but getting them fixed one at a time.

This current issue has me stumped. I've been reading a lot of threads here and have a few ideas to try out tomorrow. I think it's the converter, but not 100% sure that's the problem. Battery is draining while plugged into shore power, but only when the furnace kicks on. Battery recharges up to it's "green" light on the panel. Everything else works fine. Turn furnace back on and it drains the battery again. Someone suggested to disconnect the battery, when I did that, lights and everything still worked fine, but as soon as I started the furnace, the lights almost went out and furnace barely ran.

The battery was brand new as that was what I thought the problem was and purchased a new one.

I replaced a water heater last week and it runs fine.

I'll pull the panel off tomorrow to look at the "reset button" if equipped and pull the fuses. I'll test the AC in and the DC out with my meter. From what I can see it looks like it has a picture of a wizard on it and reads 60Amps? Will get close up of it tomorrow.

It's a 2011 Big Country. Bought used, not sure if converter is original but assume that it is.

Anything else I should be aware of? Anyone have a similar issue as this?

I bought an electric heater for tonight as it was fairly cold last night. It pulls power from the outlet without any issues. So at least we can be warmer tonight.

Thanks for reading and for any recommendations.

Happy Thanksgiving!

 

[JayArr]

Sounds like a converter issue, it should be able to run everything even without a battery if you're plugged into shore power.

When you get the meter out try this: Disconnect from shore power and turn off the furnace and any lights/pump/heater. Take a voltage reading at the battery it should be 12.6 or so. That's your battery voltage.

Now plug into shore power and wait five minutes and measure at the battery, it should be higher, indicating the battery is charging. Somewhere around 13 would be a good indication but that depends on the state of the battery.

Now disconnect the battery and measure the voltage on the wire you removed, it should be about 14.4V indicating the converter is trying to charge.

Respond here with the battery voltages for more analysis.

 

[Rene T]

Welcome to the forum. JayArr gave great advice on where to start. Can you get close enough to the converter to take down the make and model?

 

[Gary RV_Wizard]

Make the tests that Jayarr suggests to be sure the converter/charger is operating. However, sounds to me like the heater fan is drawing excessive power, maybe thru an unfused wire? It would normally require only about 5-6 amps, so easily handled for hours by a fully charged battery or the by converter alone when on shore power.

 

[Glenn449]

Sounds like a converter issue, it should be able to run everything even without a battery if you're plugged into shore power.

When you get the meter out try this: Disconnect from shore power and turn off the furnace and any lights/pump/heater. Take a voltage reading at the battery it should be 12.6 or so. That's your battery voltage.

Now plug into shore power and wait five minutes and measure at the battery, it should be higher, indicating the battery is charging. Somewhere around 13 would be a good indication but that depends on the state of the battery.

Now disconnect the battery and measure the voltage on the wire you removed, it should be about 14.4V indicating the converter is trying to charge.

Respond here with the battery voltages for more analysis.

Thanks for the test to try. Here are my results...

Step 1 reading.. 12.72

Step 2 reading.. 12.79 but dropped to 12.72 while holding meter on terminal, then it slowly started climbing back up.

Step 3 reading.. 13.74

 

[Glenn449]

Welcome to the forum. JayArr gave great advice on where to start. Can you get close enough to the converter to take down the make and model?

Thank you.
I can see the converter from a vent in the cargo bay. But I would need to remove the panel to get access to it.

 

[Glenn449]

Make the tests that Jayarr suggests to be sure the converter/charger is operating. However, sounds to me like the heater fan is drawing excessive power, maybe thru an unfused wire? It would normally require only about 5-6 amps, so easily handled for hours by a fully charged battery or the by converter alone when on shore power.

Sure hope it's not an unfused wire running that unit.

I thought it should run for hours as my other trailers had no issues. But maybe I bought it with a converter on it's way out. Day one of purchase the battery was dead. Bought a new one and it has ran for 2 months, then this happened.

Also I remembered the campground replaced a receptical and breaker on the 50 amp side as it showed low on my surge protector on one leg.

 

[Gary RV_Wizard]

It's simple enough to check converter output at the battery. A little harder to check at the fuse buss, but if the converter is pushing adequate volts at the battery terminals (13.1+), odds are strong it is fully functional. A typical converter/charger in this era pushes either 13.3v or 13.6v even if the battery is fully charged. May go to 14.4v if battery is low.

 

[Glenn449]

Thanks Gary. Sounds like I may have a different issue then?

Last night the lights brightened up for a bit, then toned down. Not dim, but still decent light. Seems to fluctuate though at times.

I'm not 100% in my understanding of a converter, my question is... will a converter still show a good charge to the battery but not put out a good 12v flow to the other parts of the trailer? Like it's only 1/2 working? Or is that not how they work?

All the fuses I have checked at the panel look ok. No red lights on in the box.

Is it safe to run a charger hooked up to the battery while still connected to the converter? Or will that cause more issues to the system? Or back to the charger?

 

[JayArr]

You're into the realm of WTF. The readings you listed are good AFAICS and the batteries should be charging and the lights should be at full brightness.

The converter should be able to run the RV without any battery at all. If it powers the RV it should charge and if it charges it should power the RV. There is only one set of outputs and they connect to the battery and all of the RV electrical at the same time.

It might be time to remove the battery and the converter and set them up on a work bench to see if they work independent of the RV.

When troubleshooting I always try to cut the problem in half, if you pull the converter and battery and they don't work on the bench then you can figure out if you got a bad battery or a failing converter.

I know you said you just bought this battery but when things get weird I always ignore that. The number of times in 25 years of repairing power supplies that I've heard "the batteries can't be the problem they're new" is innumerable.

If the converter and battery charge OK on the bench then you can go looking for some sort of parasitic short in the RV.

 

[Gary RV_Wizard]

I'm not 100% in my understanding of a converter, my question is... will a converter still show a good charge to the battery but not put out a good 12v flow to the other parts of the trailer? Like it's only 1/2 working? Or is that not how they work?

The old Magnetek 6300's used to have two different outputs, charging and buss, but anything newer than about 1999 will be a single managed load. The converter makes voltage/amps and splits it between charging and the fuse buss. You may see the brightness of lights change if the charging voltage gets ramped up considerably, but it stabilizes quickly. The fuse buss gets priority on the output amps, but the voltage is adjusted to meet battery charge needs (the charge profile). We are only talking several tenths of a volt difference, though.

The fluctuating lights indicate that a significant amp load is coming and going, forcing the converter to adjust output. It could be one of the 12v branch circuits, but it could also be the battery (or battery connection). Most late-model converters will shut off charging for a bit if the battery seems to draw excess current, then try again some minutes later. That leads to rhythmic pulsing of the lights in the evening. Jayerr mentioned this sort of thing as well. Disconnecting the battery + cable should let the converter devote itself to the fused branch circuits (but it may need battery minus connected to complete the circuit to chassis ground).

 

[Glenn449]

Thank you both for the help and suggestions. Looks like the converter might be doing its job from what you said. I'm not in a position to bench test things at this point, unless I throw it on a picnic table in the rain. But sounds like it's working anyway.

Maybe I bumped a wire when installing the new water heater or just moving things around. I'll pull the panel sometime this week when I can and start looking around.

I definitely understand about the battery possibly causing issues even if it's new off the shelf.

I still consider it a good hands on learning process even after several years of RVing.

If I get it figured out, I'll come back and post what I found, hopefully to help someone else in the future with the same scenario. Or I might have some more questions to ask depending on what I come across. Thanks again for your time and direction.

 

[Glenn449]

Looks like it was a "soft" breaker on the 50amp. Even though L1 and L2 showed 120v each.

Breaker replaced, battery fully charged and so far things are running as they should.

 

[Larry N.]

Great! Glad you found it.

 

[CharlesinGA]

I see you fixed it, but you noted the converter had a pic of a wizard on it. That would be a Progressive dynamics unit. Some of these put out one voltage but if you connect the optional charge wizard, then they become multistage. However the one with the Wizard already has the wizard inside it. Very good unit.

Charles

 

[Ex-Calif]

Strange that the 120V side should cause the DC side to fluctuate. Do you have an inverter running as well?

Glad you found it. I was gonna suggest grounds, especially on the furnace.