Why does fan run constantly when on ac power?

ScottG

Thanks, @GreatWhiteNorth. Good to know, especially since it appears to be a direct drop-in replacement. I'm pretty sure the converter in my 2015 is a WFCO-8735, so things clearly haven't changed much in that regard over the T@B's evolution. Fortunately, the converters aren't too expensive so I guess you can say RIP to your fifteen year old model. Please follow up once you complete the replacement with the Intelli-Power to let us know how it goes and any tips or tricks you can offer.

I didn't realize initially you had an older Dutchman model (though I suspected as much when you mentioned a furnace fan). You might want to add that info to your signature line so other members know your systems may not all be the same as those found on more recent T@Bs.

GreatWhiteNorth

ScottG said:

Thanks, @GreatWhiteNorth. Good to know, especially since it appears to be a direct drop-in replacement. I'm pretty sure the converter in my 2015 is a WFCO-8735, so things clearly haven't changed much in that regard over the T@B's evolution. Fortunately, the converters aren't too expensive so I guess you can say RIP to your fifteen year old model. Please follow up once you complete the replacement with the Intelli-Power to let us know how it goes and any tips or tricks you can offer.

I didn't realize initially you had an older Dutchman model (though I suspected as much when you mentioned a furnace fan). You might want to add that info to your signature line so other members know your systems may not all be the same as those found on more recent T@Bs.

Yes, Randy at Best Converter said it was direct drop in fit.  I was just reading through the specs, and it's quite the upgrade - this PD4135 converter has 5 circuit breaker AC circuits and 6 DC fused.  He said it comes with good instructions... we'll see how it goes... can document the upgrade in this thread I'd started in the Mods & Upgrades forum on our oldie T@B T2 (fiberglass skinned):

https://tab-rv.vanillacommunity.com/discussion/8323/2004-dutchmen-built-t-b-t2-camper#latest

Sneakle

Here is the reply from NuCamp to my query about my converter fan running constantly when on shore power:

Hi Mike,
Your converter should not need replacement if it is still powering all your supplies. Some converters will run their fan more than others – the only fix for the fan noise would be replacement of the converter itself.
Creed Hostetler, Technical Support Specialist

DougH

@Sneakle ;  ARGH, if your converter fan is like mine I would not want that loud fan going anytime I was plugged in.

If you cannot get a free replacement, Amazon has the 8735-P in two colors and it sounds like some folks on the forum have gone with other brands, like maybe

https://www.amazon.com/dp/B01EXKUA3E

...but there's plenty of threads on the subject.

If you're contemplating lots of solar and battery bank some day, this could be the opportunity to get a combination pure sine inverter / charger / power converter to replace the WFCO, but they're $600 or more for just 2000W.

Sneakle

I think they misinterpreted my question as me being bothered by fan noise. I'm just concerned about the fan running constantly If I leave my Tab parked at the house on shore power for weeks at a time so I can have a dehumidifier plugged in to it and running (Georgia in the summer).

dno

Hi, @Sneakle, I know this is an old thread, but I'm a new owner of a 2019 320s and have the same experience, the fan in the converter just seems to run whenever I'm on shore power, even with everything off. Did you ever resolve this?

Sneakle

Sometimes after a trip, I hook up to power at home and that little fan begins to run but is off by the next day; so I don't know what to tell you except I no longer worry about it. Someone may chime in with some info. Maybe it has something to do with charging the battery after a trip?

dno

This post seemingly fizzled out, but I'm bumping it again, since we're nigh on camping season. My converter fan runs pretty much constantly on my 2019 T@B 320S when plugged into shore power, even with absolutely nothing turned on, unless I disconnect the battery, then it stops. Conversely, I can't get the fan to turn on at all when I'm unhooked from shore power and just on the battery, even if I turn absolutely everything, including the fridge, on. Battery is comfortably sitting at about 13.4_V, according to Victron connect. The fan noise is loud enough that I don't stay hooked up to shore power at all anymore when I'm camping unless I really need the AC to work or need a charge. Glad I have solar. Any solutions surface to this problem since August 2020?

MuttonChops

@dno ; Interesting
Suggest your contact WFCO directly to see if they have any ideas.
(IMHO sounds like something in the WFCO Power Center has an issue}

Bayliss

@dno, I must have overlooked your earlier post (Aug 2020), but when this subject came up previously, I did some research on it and made the following note, which I believe I found on the WFCO site, so you might give it a try and/or ask the manufacturer tech about it:

PROBLEM: Fan constantly runs with nothing on in the camper.

SOLUTION: Pull Reverse Polarity Fuse(s). The fan should stop, meaning there is a load on the converter therefore making the cooling fan run.  If the fan does not stop, this is an indication of a failure.  [@Bayliss NOTE:  The reverse polarity fuse on the WFCO panel is fuse #7, 40 Amp - - the last fuse, down at the bottom.)

Also, here is a FAQ question and answer on the WFCO site:

Should my fan run all the time?

No. The fan is controlled by the load. The fan will start running at a low speed when you have approx. 3.0 to 6.0 DC Amp draw. It will increase in speed as you add more load until you have approx 14.0 to 15.0 Amps draw. At this point, the fan is at its maximum speed and will stay there even if you add more load, Should amperage drop below 3.0 to 6.0 DC amps, the fan will shut off.

dno

@Bayliss, thanks, will try that in the morning.

Tabaz

Went camping this weekend on shore power.  The converter would cycle on and off every few seconds.  OMG, thought something was seriously wrong with my trailer.  After about five minutes of this behavior, it finally settled in. No problems the rest of the trip.

Bayliss

@dno, if the pulling the reverse polarity fuse does not answer the question presented, I would suspect that there is an issue with your battery.  If the converter is using a lot of power to attempt to charge-up the battery, that would cause the fan to run continuously.  Since you apparently purchased your 2019 320 S in 2020, I am assuming that you purchased it from a previous owner.  It could be that the previous owner did not properly charge/maintain the battery.  Therefore, as discussed earlier in this thread, you should disconnect the battery from the trailer wiring and let it "rest" for an hour or so, and then test the battery state of charge (or take it to an auto parts store and ask them to test it for you.)  If you have a wet cell battery, be sure to also check the water level to each cell.

dno

@Bayliss, thanks for all your suggestions and information. The problem now has become kind of erratic. I went into the trailer to try pulling the RP fuse and for the first time in forever I found that the fan has stopped. I can't get it to come on with any combination of battery connected or disconnected, shore power connected or disconnected, all electrical appliances on, etc. All I know is the next time I try to sleep in it, it's sure to turn on again for no apparent reason (unless it died?). 
I bought the trailer second hand from a dealer in San Diego. I replaced the battery (the original, I assume, this trailer was barely used) with a Battleborn LiPo not long after I got it. In my carport it hovers at a float charge of about 13.5V from shore power. It also gets a couple of hours of (high desert) sun on the solar panel every day. So the converter should not be working very hard or very long ever to keep the battery topped up.

Marceline

dno said:

@Bayliss, thanks for all your suggestions and information. The problem now has become kind of erratic. I went into the trailer to try pulling the RP fuse and for the first time in forever I found that the fan has stopped. I can't get it to come on with any combination of battery connected or disconnected, shore power connected or disconnected, all electrical appliances on, etc. All I know is the next time I try to sleep in it, it's sure to turn on again for no apparent reason (unless it died?). 
I bought the trailer second hand from a dealer in San Diego. I replaced the battery (the original, I assume, this trailer was barely used) with a Battleborn LiPo not long after I got it. In my carport it hovers at a float charge of about 13.5V from shore power. It also gets a couple of hours of (high desert) sun on the solar panel every day. So the converter should not be working very hard or very long ever to keep the battery topped up.

When you travel do you run your 3-way fridge on DC power? It seems like many (most?) vehicle alternators can't keep up with that, so if you drive 4-5 hours you could run quite a deficit, which would cause the converter to run a fairly long time when you plug the trailer into shore power.

dno

@Marceline, yes, sometimes, but this problem happens even after I've been plugged into shore power and fully charged for months. And my battery does seem to charge ok from my Ridgeline's alternator.

Marceline

dno said:

@Marceline, yes, sometimes, but this problem happens even after I've been plugged into shore power and fully charged for months. And my battery does seem to charge ok from my Ridgeline's alternator.

You said earlier "Battery is comfortably sitting at about 13.4_V, according to Victron connect."  Can you clarify? Do you have a Victron monitor or is that a reading from the Victron solar controller? If you have a Victron battery monitor, does it show 13.4V when you've disconnected from shore power and let the battery "rest" awhile with no load on it? 

dno

It's from the SmartSolar controller. Yes, it holds voltage fine off of shore power, at least 13.4V, usually more. Float voltage is set at 13.5V

Marceline

dno said:

It's from the SmartSolar controller. Yes, it holds voltage fine off of shore power, at least 13.4V, usually more. Float voltage is set at 13.5V

Someone else can jump in, but does the solar controller accurately measure the battery voltage? I thought that a separate Victron monitor is required for that.

Sharon_is_SAM

I asked @pthomas745 that same question not long ago.  I believe the voltage difference between the battery monitor and the Victron charge controller is very small, however, the battery monitor factors in other variables and comes up with a % State of Charge.

dno

Yesterday I unplugged the shore power and ran the battery down to about 13V, then plugged it back in and charged it up. The fan ran while it charged until it reached 13.5V (float charge) and then stopped, as one might expect. Seems to be working as it should for now. Hmmmmm....

Bayliss

@dno, I would say that is a "win" for you.  Thanks for keeping us updated on the status of the issue.

Marceline

dno said:

Yesterday I unplugged the shore power and ran the battery down to about 13V, then plugged it back in and charged it up. The fan ran while it charged until it reached 13.5V (float charge) and then stopped, as one might expect. Seems to be working as it should for now. Hmmmmm....

I strongly suspect that when the converter fan was running incessantly you had run the battery down a lot more than you believe, so the converter had to run quite a while to make up the deficit. Perhaps you confused the voltage reading from a power source (converter or solar controller) with the voltage of the battery.