? electrical problem...what’s happening? Should I worry?

[kabbro]

I am prepping and cleaning travel travel for upcoming trip...had the unit plugged into my 30amp connection at home, was inside with only the air conditioner running and 3 overhead lights in trailer on...suddenly the output in the lights decreased to about 25% of normal output, stayed that way for maybe 15 to 20 seconds and then gradually reverted back to normal.....about 5 minutes later the same thing happened, again reverting back to normal output. When this occurred the ac was running steadily, hadn’t just turned on or cycled or anything (at home when the air kicks in I can often see a minimal sudden lowering of light for a fraction of less than a second)...my wife said nothing was going on in the main household electrical input or output.

I would appreciate any ideas about what may be occurring and whether this needs to be pursued further at this time (probably won’t be using the air on trip, though not certain this has to do with ac....have used ac a lot with this never happening before)

Thank you for any help.

[pappy43756]

Had a similar problem last fall and this spring,lights kept dimming.
Converter finally died and after I put a new one in no more problem.

[enblethen]

Converter output seems to be working. Now test at 12 volt DC battery connection, then go immediately to the battery and check voltage on battery. Readings should be nearly the same allowing for slight voltage drop. Maybe .1-.2 volts

[time2roll]

Take the voltmeter with you on the trip. If you have a portable battery charger, take that too.

[DrewE]

Your converter does seem to be working more or less properly, at least at the moment. About the only other easy check would be to turn off the AC power and see how it reacts to loading only on battery power (no need to run the battery down too much--just see if the battery voltage and brightness both stay in the reasonable range as you turn on more lights, etc).

You may very well have had a loose/poor connection at the battery that happened to get corrected in the process of checking things out.

[kabbro]

Update: I had the battery load tested; was assured that the battery is ok. So, I hauled the trailer home, have hooked it up to 30amp shore power in the yard. I decided to try a “lazy-man’s” approach before removing the panels to the electrical board and converter and learning how to test the converter (but thanks to enblethen for the link to the schematics if I later have to do this). Checking the starting voltage on the battery was above 13 volts, inside the trailer I heard the converter humming along at the beginning, so presumably it is charging or trying to charge. So, I have turned on every light in the trailer. At about 12 hours the voltage at the battery was 12.76, this am at 24 hours it’s 13.64 (and the lights are continuing to shine brightly)....am I correct. in concluding that the converter and system is intact? I am not hanging out in the trailer so don’t know if there has been any temporary dimming of the lights like I described in the original post. Maybe the reason for the original dimming which prompted this search will forever remain a mystery and hopefully not recur? If any readers think I should pursue this further I would welcome their advice since, after all, I am attempting to be proactive rather than have a problem on the upcoming trip. Thank you.

[enblethen]

OPs converter is now 55 amp. I would not go any less.

[time2roll]

Battery holding 12.56 disconnected in storage does not seem bad. A few lights running the voltage to 12.3 seems normal enough.

Need to plug the WFCO in and see if you get 13.6+ volts out of it.

I recommend a Powermax if the WFCO needs replacement.

https://powermaxconverters.com/product/pm3-mba/
The 35 amp is fine.

[kabbro]

kabbro wrote:

enblethen wrote:
Fairly late model converter with three stage output.Owner's manual
Some troubleshooting system on page 7.
Sounds like bad battery!

Enblethen (and everybody else): Thank you. I will take the battery to a shop and have it tested, and am perfectly willing to have the battery replaced as that would be the least expensive option—but I am thinking that a starting reading if 12.56 volts and ending reading of 12.6 after 48 minutes of ldrawing lighting etc is not too bad...what say those who are more knowledgeable than me? Thanks!

c
Correction: ending voltage was 12.3 volts

[kabbro]

enblethen wrote:
Fairly late model converter with three stage output.Owner's manual
Some troubleshooting system on page 7.
Sounds like bad battery!

Enblethen (and everybody else): Thank you. I will take the battery to a shop and have it tested, and am perfectly willing to have the battery replaced as that would be the least expensive option—but I am thinking that a starting reading if 12.56 volts and ending reading of 12.6 after 48 minutes of ldrawing lighting etc is not too bad...what say those who are more knowledgeable than me? Thanks!

[enblethen]

Fairly late model converter with three stage output.Owner's manual
Some troubleshooting system on page 7.
Sounds like bad battery!

[kabbro]

Update: went to the storage building. First thing was to test voltage with a voltmeter (negative terminal on battery is always disconnected in storage)...starting voltage was 12.56 volts...connected battery and went in to check out converter...had 3 lights on and slide in-and-out...there was not a decrease in lighting during the 48 minutes I was in-and-out...tested voltage at the end and it was 12.30, took battery home and is now charging.

Re: converter...factory check-list at buildout identifies converter manufacturer as CHENG...trailer is Model Year 2009. 99% sure this is original converter (I purchased trailer used)...apparent Model Number is 351-ED49001. YJ 0808 E237684-SBI-4-2

Also, looking at the whole panel including the circuit breakers and apparently converter there is a listing of WF8955 PEC.

Googling all of these numbers doesn’t seem to result in an exact match of numbers but seems to get one into WFCO or converters avail on Amazon and other sites.

Appreciate any thoughts or insights or suggestions. Thanks

[ken56]

I had an AGM battery that was 4-5 years old when my slides started working slowly. Took the battery to where I had purchased it, a Batteries + bulbs store, they tested it and said it was good. I took it home and reinstalled it and put it on the charger over night. Still the slides were sluggish and didn't act quite right. Took the battery back to them and they checked it again, said it was good. I bought a new battery anyway. Took it home and put it in and like magic the slides worked as normal. Still do after 2 seasons. Just because they say a battery is fine doesn't mean it is.

[jdc1]

Who installed the RV wiring? Are you getting 30 amps from tat outlet? How far is the electrical run? What size wire was used? And, how long is the RV cord?

[valhalla360]

wa8yxm wrote:
Ok the lights going DIM then brightening back up suggests something is drawing one HECK of a lot of 12 volts.
One possibility is bad batteries (They suck the converter down) as suggested up in fact I'd rate 'em high on the list and there are often self-resetting thermal breakers in the main battery line. along with other types that you need to manually reset depending on the RV.

It is also possible something else is sucking 'em down.

My bet is the reverse:
- When the charger is on, you have nice high voltage (somewhere on the order of 13.5-14V) ...the lights burn brightly as the charger compensates for a failing battery.
- When the charger shuts down, it's only the bad battery feeding power and since the battery is bad, the voltage quickly falls to maybe something like 8-10V...and the light burns dimly.
- On seeing the low voltage, the charger kicks back on and the cycle repeats.

Most any autoparts store will load test a battery for free. While it's not really the right test for an RV house battery, if it fails, it's good enough to show you have a bad battery.

If you have a multimeter (which is a good idea...and learn how to use it), disconnect the shore power and check the voltage after an hour or so. You can check sooner but voltage is really only a good measure if the charging source has been off for a while. You should see something north of 12.6-12.7 volts. Certainly if it' down around 12.0 or lower after sitting with no loads after being charged, that's an indication of a bad battery.

It's possible it's something else but I'm betting battery.