Ghost in the Converter

[BlindGuyNAR]

So I feel like I have a good understanding of the function of converters and basic troubleshooting of them.

Mine is tripping me out though.

Last year after being plugged in for 3-4 weeks I unhooked and tried to pull in slides and noticed battery was nearly dead. I tested batt voltage and it was low. I was unhooked so converter wasn't on. Plugged back in a voltage was mid 13's which tells me converter was working. I checked water level in batt and since it was fine I figured bad cell. Since I was plugged back in I ran in slides with no issue.

Since I was headed out on a couple week trip I just bought a new batt and it was fine entire trip and the rest of the summer. Even being plugged in for a couple weeks at a time afterwards.

When I got back I threw the old batt on a charger and it came up to 100%. I even had it load tested and it passed. While this was strange I just used the old batt in my boat which has worked without issue and forgot about it. As a note this batt was only 6 months old so a bad cell was unlikely anyway.

Trailer sat unplugged all winter hooked up in trailer with batt cutoff switch off. Over the entire winter it only lost about 20% of its charge.

Plugged it back in a few weeks ago and well now the trailer is doing it again.

I'm plugged in and if I turn the converter.off via the breaker is see batt is dead. I tested the volts at the batt. With converter on the volts are 13.38 off low 10.27. Again I check water level and it is fine. Since I am doing tests at the batt and see voltage increase when converter on I assume converter is wired right is pushing power rather than pull from the batt, This is with the new batt as old one is still in my boat.

I know the converter is putting out a lot of amps as my slides running in pull 24+ amps and since batt is dead the converter is producing all of them. I hear converter fan spool up during slide in/out so again it seems to be working. Even though I have all LED lights I see them brighten up with turning breaker on then dim slightly when flipping off.

Basically everything seems to suggest converter is ok and batt I know is good as well.

I have a WFCO 75 amp converter Model WF-9875

The manual says it's a 3 stage converter so batt boiling shouldn't be an issue.

Anyone have a suggestion? I don't mind buying a new converter, but as this one seemingly works I can't justify it.

[JRTJH]

Have you checked the reverse polarity fuses in the converter? It is possible that "somehow" either the battery was hooked up backwards, or for some reason those fuses "blew". Their sole purpose is to protect the converter from reverse polarity by "blowing" which effectively removes the battery from the converter circuits. It may be that one or both of those fuses are open and what you're reading when plugged in is the converter voltage (13.6 VDC is consistent with the rapid charge voltage and 13.3 is consistent with normal DC output) and when the trailer is unplugged from shore power, the battery has never been charged because those fuses have "disconnected it from the converter"..... Just a hunch.....

[BlindGuyNAR]

Originally Posted by JRTJH

Have you checked the reverse polarity fuses in the converter? It is possible that "somehow" either the battery was hooked up backwards, or for some reason those fuses "blew". Their sole purpose is to protect the converter from reverse polarity by "blowing" which effectively removes the battery from the converter circuits. It may be that one or both of those fuses are open and what you're reading when plugged in is the converter voltage (13.6 VDC is consistent with the rapid charge voltage and 13.3 is consistent with normal DC output) and when the trailer is unplugged from shore power, the battery has never been charged because those fuses have "disconnected it from the converter"..... Just a hunch.....

Could it have been hooked up in reverse? Well not since I took ownership, but dealer hooked up first batt so they could have.

I understand what you're saying and I'll certainly check them, but if I'm checking voltage at the batt terminals and seeing 13.4 when converter is on wouldn't that mean the converter and batt still have a circuit?

If those fuses were blown I'd suspect no volt rise at batt terms with converter on.

Is my logic wrong there? Seriously I hope it is something that easy as I've ran out of ideas.

If this does turn out to be the issue I guess all my charging was coming from the truck while traveling. Certainly possible I guess.

[BlindGuyNAR]

Originally Posted by JRTJH

Have you checked the reverse polarity fuses in the converter? It is possible that "somehow" either the battery was hooked up backwards, or for some reason those fuses "blew". Their sole purpose is to protect the converter from reverse polarity by "blowing" which effectively removes the battery from the converter circuits. It may be that one or both of those fuses are open and what you're reading when plugged in is the converter voltage (13.6 VDC is consistent with the rapid charge voltage and 13.3 is consistent with normal DC output) and when the trailer is unplugged from shore power, the battery has never been charged because those fuses have "disconnected it from the converter"..... Just a hunch.....

To be clear on the fuses they are the 2 or 3 fuses on the outside of the converter next to the DC wires going into the converter right?

[JRTJH]

If you are checking voltage at the battery terminals and getting 13.3 VDC, then it probably isn't the fuses. In that case, I'd think something in the converter charging circuit is bad ??? Have you checked the WFCO website for troubleshooting guides? They have an excellent one at this link: Download the MANUAL and on page 5 is the troubleshooting information.... In that manual WFCO says, "To check the converter output, the battery must be disconnected" ??? First I've read that, but it may be giving you a false reading if the battery is connected ????

http://www.wfcoelectronics.com/Image...erDocs/7-3.pdf

And yes, the reverse polarity fuses are the 30 or 40 amp "green" fuses (big ones) on the outside of the converter....

[JRTJH]

I just had a crazy thought.... Have you checked the 30 amp autoreset DC breakers on the positive battery wire? They should be mounted on the bulkhead right by the battery and have a red vinyl "cap" on them. Probably 2 pretty close to each other... If one of them is corroded, it would provide enough DC voltage to read on a VOM, and you'd get the 13.3 VDC, but when you apply power to charge or use the battery, the amperage just wouldn't flow through the corroded contacts.... I know, crazy idea, but take a screwdriver handle and beat them a few times or just replace them if they look bad... About $2 each...

And, WFCO tech support at
574-294-8997
877-294-8997 (Toll Free) has been really good at helping members who are "stumped"

Good Luck

[gvansickle1]

Originally Posted by JRTJH

I just had a crazy thought.... Have you checked the 30 amp autoreset DC breakers on the positive battery wire? They should be mounted on the bulkhead right by the battery and have a red vinyl "cap" on them. Probably 2 pretty close to each other... If one of them is corroded, it would provide enough DC voltage to read on a VOM, and you'd get the 13.3 VDC, but when you apply power to charge or use the battery, the amperage just wouldn't flow through the corroded contacts.... I know, crazy idea, but take a screwdriver handle and beat them a few times or just replace them if they look bad... About $2 each...

And, WFCO tech support at
574-294-8997
877-294-8997 (Toll Free) has been really good at helping members who are "stumped"

Good Luck

I'm going to check this out tomorrow on mine as I half wonder if this isn't at least part of my problem. We just bought it last month and its a new Trailer but... it's a 2013 model; i.e. it sat at the dealer for at least a year!

[BlindGuyNAR]

Originally Posted by JRTJH

I just had a crazy thought.... Have you checked the 30 amp autoreset DC breakers on the positive battery wire? They should be mounted on the bulkhead right by the battery and have a red vinyl "cap" on them. Probably 2 pretty close to each other... If one of them is corroded, it would provide enough DC voltage to read on a VOM, and you'd get the 13.3 VDC, but when you apply power to charge or use the battery, the amperage just wouldn't flow through the corroded contacts.... I know, crazy idea, but take a screwdriver handle and beat them a few times or just replace them if they look bad... About $2 each...

And, WFCO tech support at
574-294-8997
877-294-8997 (Toll Free) has been really good at helping members who are "stumped"

Good Luck

I know the breakers your talking about and I'll check them.

I almost wonder if something about disconnecting the batt resets something in the charging circuit of the converter as it seemed fine the rest of last year after batt replacement which involved a disconnection.

[BlindGuyNAR]

Breakers show no signs of Corrosion. With batt disconnected I get 13.69 volts on the batt cables. Battery was 10.72v and when connected to cables battery 13.59v.

The tech support number was a waste of a ph call. Guy named John just told me what I described was impossible. To say I couldn't get a word in edgewise would be a nice way to say it. John must've been overdue for lunch or break cause he didn't have anytime for me. The only thing he kept saying is I must have a bad battery and to replace it. If voltage exists when disconnected then it's not a converter issue is all he kept saying.

When I told him I did replace batt he said I must have got two bad batts in a row. I tried to explain these were diff brands so it was unlikely he said I just had bad luck and got two in a row. I tried to explain batt #1 was in service on my boat without issue he just again said it was impossible.

Pretty worthless conversation. I felt like arguing my points, but didn't see anyway possible to change his mind and get some actual suggestions so I politely said thank you and we ended the call.

What I now suspect is happening is something is the charging circuit is screwing up and only sending like 1/4 amp to the batt thus letting the normal draw of stereo, co2 alarm, etc slowly kill battery. A batt dis/reconnect resets the charging circuit and resolves the condition until the next time. That 1/4 amp gives me my 13.69 volts, but doesn't keep batt charged.

I think my fluke F-177 multimeter can measure amps, but as I have to disconnect cable to hook it up I'd get false readings since a dis/reconnect resolves it temporarily so it's of no help.

This issue doesn't seem to effect the converters ability to ramp up and provide bulk amps when required for running in slides etc.

Before I disconnected batt I pulled off caps and saw no bubbles and listened and heard no gurgling sounds. After reconnecting batt I saw bubbles and sounds within 15 sec and after about two hrs batt tests disconnected at 13.04 volts. Quite a bit better than 10.72v from before.

I also have never have seen the bulk charge voltage of 14.4 as the manual states should occur for 4 hrs if batt volts go below 13.2.

I suspect a converter purchase in my future. Based on WFCO tech support I'll likely pick a different brand. Just to be sure though I plan on having batt#2 tested before the purchase.

[JRTJH]

Sorry about your WFCO "tech support" experience. It must have been a bad day for that John and he was looking for lunch more than helping customers

Progressive makes a "slip in the same hole" converter/charger that is a 1:1 exchange. If you're buying a new one, Progressive deserves at least a look-see.....

I'm at a loss as to why the "impossible" is happening, unless there's some relay or electronic switch that isn't resetting on the control board ??? Good luck trying to find the issue, I'm "suggested out"

[Bob Landry]

The converter uses an on-board relay to switch the trailer from battery power to converter power and battery maintenance. Relays use various components to "latch" them and these can develop intermittent problems. A charging relay in the converter dropping out would give the symptoms described. The battery would supply house power until it ran down from not being charged by the converter.

While on shore power,monitor the state of charge on the battery by checking voltages. it should be obvious which level of charge the converter is putting out. Without being there to measure and monitor voltages, I'm SWAGing towards the converter being bad.

FWIW, I have not read many stellar reviews on WFCO converters.

[Hoojs12840]

I'm having the same issue. Charge off truck but not shore power. relays look good battery is 6mths old and takes charge from truck


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[JRTJH]

There are two circuit breakers mounted into the wiring loom at the front of the trailer. They are connected to the positive battery cable. Although they may "look good", corrosion can cause them to be inoperable. I've seen them bad on trailers less than 3 months old and I've seen them still functioning on a trailer that was 15 years old. Check them carefully to make sure you have 12 volts on each of the terminals to ground.

Then, if they are OK, check the two "reverse polarity" fuses on the converter. They are usually located beside the 12 volt fuse block in the power center. In the attached picture, they are the two red 40 Amp fuses located just left of the fuse panel.

Here are pictures of the circuit breakers (usually covered with a red vinyl cover) and the reverse polarity fuse location.

If the battery is good, both the circuit breakers and the reverse polarity fuses are good, chances are it's the converter. Follow the "converter troubleshooting guide" in the WFCO owner's manual to be sure.

Good Luck

[Fishhawk]

You might have tried this already?
Since the convertor and battery appear to be doing their job

I would disconnect, clean and re-connect all wiring connectings from the
convertor to the battery
Looking closely for corrosion and loose connections and damaged wiring as you go

A corroded or loose connection can easily "Ghost"
a voltage reading to a meter
But
can not supply adaquate amperage to actually operate anything

Hope this helps

Hawk

[GMcKenzie]

Can you get an inductive ammeter and test with it so you don't have to disconnect? Sounds to me like you aren't getting amperage to the batteries but I understand that disconnecting makes the problem go away.

I guess an alternative is to add a disconnect switch and just disconnect periodically.

[Hoojs12840]

It has a disconnect switch from the factory. I'm going to disconnect the battery and see what I get from the convertor. If nothing I will disconnect and clean and reconnect everything. Everything is new and doesn't show any issues but you never know. Can I get the DC circuit breakers at an auto parts store if I need them?

I have a multimeter so I should be able to get an idea what isn't sending.

Thanks for they ideas. Hopefully it's something simple.


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[zuley]

Have been reading and following this post but have not added to it as I am not certain my thoughts are correct. My initial thought was in fact the two circuit breakers inline with the positive cable. If I may ask what function do they serve when in fact the system is fuse protected? I run dual batteries on mine and this past spring I added a battery shut off switch on the tongue. When doing my rewiring one of the circuit brakers granaded. After one year both were pretty much corroded but they obviously still worked or at least still allowed current to pass through them. Eliminted them completely. What is there purpose?

[Bob Landry]

My thought is that the circuit breakers are for the slides or perhaps another high current draw device. I base that assumption on the fat that I have two slides and two C/Bs. The only converter protection I've seen are the two polarity fuses at the converter. On battery setups that do not use a battery cut-off switch, a 30A fuse in an inline fuse holder from the positive terminal is all I've ever seen.

[Hoojs12840]

I have 3 slides and only two circuit breakers.

1.Checked all connections for loose or corrosion. Nothing at all out of place.

2.Only inline fuse was 30amp (looks like for landing gear) and it was good

3.Two fuses in convertor were good.

4. Battery shows 10.55 when no power to rv and battery disconnect knob engaged.

5. Battery shows 13.2v when rv is plugged in to shore power and battery disconnect is disengaged.

Seems like the convertor is sending power to battery and I can here it working when the battery is engaged.

Only think I can think is the battery is bad? 6mths old, but it's not as large a battery as I had in my 26ft TT and it has always seemed to take long time to charge, but it seems to charge off my truck. Only way to test that I think is to hook up the power and let the truck idle for a few hours.

Thoughts?



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[Hoojs12840]

Here's the battery.



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