Converter charging (mis)behavior

[wingerbls]

Still in my first full season in my Sundance XLT, so I'm learning a lot. There is one thing I've noticed that puzzles me; hopefully some of the experts out there can chime in.

I have the WFCO 8900 series converter and two GC batteries in series. I had the coach sitting at home, not plugged in, so it was just slowly draining the batteries. I had a trip coming up so I went to charge the batteries by plugging in the coach to shore power. As I was working around the unit, I heard a slight clicking noise; I found it to be one of the little circuit breakers by the battery pack. I went inside the coach to see what the battery monitor was showing. It was at 65% capacity or so; when I checked the current draw, I saw the current go to around 17-18 amps (charging), at which time it reversed and went to zero for a few seconds, then repeated. I'm assuming that the breaker is heating up when the high-current is going through it, tripping, then resetting when it cools, starting the cycle again. (Must be an automatic breaker...?)

This seems abnormal to me. Does the WFCO converter not limit the current when charging the battery? Or is it supposed to and my converter is just not operating properly? As it stands, I cannot dry camp for any length of time and then plug in to charge my batteries with the converter (which is why I bought the GC batteries to begin with!). I can plug in a regular battery charger directly to the batteries, but it doesn't seem like I should have to do that.

Is a Progressive converter in my future?

Thanks for any light anyone can shed (if you'll pardon the bad pun...).

Brian

 

[danemayer]

Hi wingerbls,

There is a 12V mini-circuit breaker near the battery that is in between the battery and the power converter. It's usually one with a manual reset, but it might have been replaced with an auto-reset breaker at some point. If it's auto, and it's tripping, you should be able to measure the voltage at the battery terminals and watch the voltage go up and down. Check the voltage with shore power disconnected. Then plug in and check. When being charged by the power converter, it should read > 13 V DC at the battery. If it clicks and voltage drops, the breaker is tripping for some reason.

Next step might be to measure voltage at the top contact of the 12V mini-breaker. If there's a problem with the mini-breaker, it may trip, but the voltage at the top terminal (going to the converter) should not drop when the breaker trips. If the voltage drops on the converter side of the breaker when the breaker trips, the problem may not be with the breaker.

It may be that the clicking is from the converter itself shutting off. You might check your shore power connections and receptacle. If voltage falls below 105 V AC (I think), some converters will shut down.

And don't overlook the possibility that one of your batteries has a shorted cell.

 

[JohnDar]

Could be the WFCO. My neighbor at the CG was having problems with his battery not charging. I measured the output at the converter and got 12.26V. Same at the battery. A few minutes later, the voltage at the battery was only 10.3V and the same at the converter. Thing is supposed to put out at least 13.6V during charging. His park model rig is a 2012 model.

 

[brianharrison]

Keep in mind the OEM battery monitor is measuring voltage. You do not say if you have a true battery monitor that measures cummulative current withdrawn (ie amphours). So at 65% you are probably reading 12.3 to 12.5V (reference link to open circuit "state of charge" vs voltage).

Good advice from Dan above to measure voltage at contacts throughout the circuit with a digital Volt-Ohm meter.

If it is the converter (mis)behaving, I learned in my research while replacing my brother in law's WFCO 8900 that Progressive Dynamics has a 4600 series direct replacement converter, and paired with the charge Wizard Pendant, turns the charger into a 4 stage "intelligent" charger. I believe the WFCO is single stage.

With your two expensive GC batteries, I highly recommend a better, intelligent charge.

Brian

EDIT - if your batteries are really dead (ie less than 10V while at rest) then the current from the WFCO will be really high (as you measured) - tripping the autoreset circuit breaker integral with the WFCO. If you charge the batteries with a good external charger to bring them back to life, you can use the WFCO to charge after that as the amperage will be lower.

 

[Jim.Allison]

The 4 stage is a must for 225 amp hours and to care for those batteries. Get the pendant too if its available for the direct fit. (if you have to buy a new charger)

 

[wingerbls]

Thanks for all the great tips. I don't have my multimeter with me at the moment, so I'll have to sleuth it some more when I get home.
The batteries are new this spring. After the initial charge I measured them with a hydrometer and all cells were at spec. I also have a true battery monitor (Bogart Engineering TM 2025-RV) that measures 13.6 V when hooked up to shore power, as the manual states. The converter claims to be a 3-stage converter, and it DOES charge the batteries, but the trouble comes when they are more deeply discharged than a few percent.

My main question was whether or not the converter limits charging current in any way. The data from the battery monitor seems to indicate that it does not, which I find interesting...

Jim Allison, thanks for the tip on the 4-stage converter. That may be next year's upgrade...

 

[branson4020]

Its not unheard of for these coaches to have incorrect breaker wiring. The breaker between the converter/12V fuse panel and the battery should be a 50A manual-reset. Sounds like you have the wrong breaker installed. I have a PD9160 converter charging a pair of GC batteries and have actually had it trip the 50A breaker when recharging a deeply discharged battery pack.

 

[2manysecrets]

I'm having trouble with blowing power converters (2 in the last 4 months). WFCO WF-9865, 65 amp.this on an Elkridge with 2, deep cycle batteries being charged by roof top solar panel. Can't seem to figure it out. Any observations or suggestions?

 

[danemayer]

I'm having trouble with blowing power converters (2 in the last 4 months). WFCO WF-9865, 65 amp.this on an Elkridge with 2, deep cycle batteries being charged by roof top solar panel. Can't seem to figure it out. Any observations or suggestions?

How long was the solar panel installed before you started blowing converters?

 

[Jim.Allison]

When you say blown you mean they are burned up and no longer function, or they throw the breaker, or they blow internal fuses?

The first thing I would do is separate my solar charging system from the charger, so that the two systems are isolated. Then I would check to see if the solar is still functional. If it is then charge with that until you can figure out why the charger is malfunctioning. Once you get the two systems isolated you can use a multimeter to run down the problem. If you don't have one already lowes carries a good digital multimeter by southwire,

Your charger should be protected by either a circuit breaker or a series of DC fuses. You should not be able to miswire it and damage it. Not saying it could not happen, I would be looking for blown DC output fuses.

I'm having trouble with blowing power converters (2 in the last 4 months). WFCO WF-9865, 65 amp.this on an Elkridge with 2, deep cycle batteries being charged by roof top solar panel. Can't seem to figure it out. Any observations or suggestions?

 

[2manysecrets]

Blown to me means, it will no longer convert. First symptom is when hocked up to a 50 amp land line, the lights in the trailer will brighten then dim. This will happen about
every 30 seconds. When I check out the inverter, the fan isn't running and the 2 40 amp fuses in the unit itself are blown. When I replace them, they will instantly blow
again. At this point I am not running anything but the overhead lights and the TV. I first had this happen about mid May. I bought a new one, hooked it up and it worked well up to 9-19, 2014. It started doing the same thing over again. Now I never blow the fuses in the fuse panel, just the converter itself. As it is under warranty, I have requested a replacement from WFCO but am trying to figure out why this is happening. Not being a real good electrician, I get confused about what I am doing and checking and what I should be looking for. I suppose I should take it to an RV repair station but really don't want to spend $1000 finding out I had it hooked up backwards.

 

[danemayer]

Not being a real good electrician, I get confused about what I am doing and checking and what I should be looking for.

All the more reason to disconnect the solar installation. After the converter problems are behind you, before hooking the solar back up, have a solar expert review the installation.

 

[2manysecrets]

Dan, thanks. I'm going to do some more checking this evening. The only thing that changed since we bought this unit is that we had the dealer add the solar charger they threw in an additional battery. I have no installation instructions for this solar panel. I'm going to see if I can get something that speaks to proper installation.Thanks again.

 

[Jim.Allison]

A digital multimeter will indicate polarity also. I have one dedicated to the fiver so I don't have to worry about leaving it behind. Its a lifesaver. Mine has a handy user guide, it takes about 30 minutes to learn how to accomplish 99 percent of everything you will ever need to know in a fiver. The rest you can learn if, and when you need to know it.

 

[vicrider]

Hi wingerbls,

There is a 12V mini-circuit breaker near the battery that is in between the battery and the power converter. It's usually one with a manual reset, but it might have been replaced with an auto-reset breaker at some point. If it's auto, and it's tripping, you should be able to measure the voltage at the battery terminals and watch the voltage go up and down. Check the voltage with shore power disconnected. Then plug in and check. When being charged by the power converter, it should read > 13 V DC at the battery. If it clicks and voltage drops, the breaker is tripping for some reason.

Next step might be to measure voltage at the top contact of the 12V mini-breaker. If there's a problem with the mini-breaker, it may trip, but the voltage at the top terminal (going to the converter) should not drop when the breaker trips. If the voltage drops on the converter side of the breaker when the breaker trips, the problem may not be with the breaker.

It may be that the clicking is from the converter itself shutting off. You might check your shore power connections and receptacle. If voltage falls below 105 V AC (I think), some converters will shut down.

And don't overlook the possibility that one of your batteries has a shorted cell.

Danemayer, I have a issue with my 12 volt, converter doesn't seem to be recharging batteries. I have 3 yo 3585rl bh. Voltage on batteries is 11.62,basically dead yes? I put leads of multimeter on the 2 open spots on converter and it showed 13.68 plugged into shore power. we're in route from Port Or, to tucson. Slides wouldn't close this am without a borrowed battery charger connected to one of the batteries, can you help I'm at 5035192597.

 

[danemayer]

Danemayer, I have a issue with my 12 volt, converter doesn't seem to be recharging batteries. I have 3 yo 3585rl bh. Voltage on batteries is 11.62,basically dead yes? I put leads of multimeter on the 2 open spots on converter and it showed 13.68 plugged into shore power. we're in route from Port Or, to tucson. Slides wouldn't close this am without a borrowed battery charger connected to one of the batteries, can you help I'm at 5035192597.

In between the power converter and the battery is a 12V mini-circuit breaker. If that trips, the converter doesn't charge the batteries. One of the key symptoms of a tripped breaker is that if you unplug from shore power, all your interior 12V lights go out. As the battery voltage drops, the hydraulic pump, which draws a lot of current from the battery, is one of the first things to stop working.

Here are a couple of pictures of the circuit breaker showing the teeny-tiny, very hard to see reset button, and the overall buss bar structure with a row of the mini-circuit breakers. They'll be located near the batteries.

We have a more thorough explanation in our owner-written 12V Block Diagram and Troubleshooting Guide.

 

[vicrider]

Thank you! That's what it was!

 

[wingerbls]

branson4020 hit it on the head. I found that the converter is wired to the batteries through a garden variety 15A auto-reset breaker. That'll get fixed before next season...