Electrical Troubleshooting

[ckapavik]

Howdy.

I am looking to troubleshoot a potentially bad converter in a 2019 Airstream Flying Cloud 20FB. Whenever the trailer is connected to shore power, I am getting a reading around 16-17 with the batteries (lead) connected. With the batteries disconnected, I am getting a readout of 17 with occasional readings around 14.8. Then it bumps up to 17 again. Using both the digital readout from the SeeLevel II and a multimeter. The SeeLevel II readout will also sometimes display 'Sht' (for short). This is a WFCO WF-8955PEC-J converter, still original. Does my testing and logic above indicate this converter has an issue and should be replaced? Or should I continue to dig further before going down that path? Everything works fine when we are not connected to power if I reconnect the batteries and voltage appears good. I have not tried charging via solar yet, I can try that tomorrow.

Thanks in advance,
Cole

[uncle_bob]

Hi

Assuming these are battery voltages and not something else .....

If you are reading 17V on a battery at the posts, that battery is toast. If it's a flooded cell, it may be dry. Still it's likely toast.

If the converter really puts out 17V then it is toast as well. If you have two devices ( Sea Level and multimeter) that agree on the 17V ... toast. If your two readings do not agree, then check those devices.

Bob

[gator.bigfoot]

What voltage are you getting when not connected to shore power? Have you load tested the batteries?

17 volts is very high, but won't necessarily kill a flooded cell. At that voltage you're on the upper end of the equalize stage. The charger isn't a 4 stage charger so it shouldn't be that high. So my guess is that the charger is bad. The good news is that if you have a decent solar charger then you don't need the shore power one. Mine is disconnected and has been for over 6 years now. I just use the 300 watts on the roof, which with the old panels up there is probably 200 at best. But it works fine. I've never seen more than 13 amps of charging even in the best sunshine.

My advice is try to test the batteries and see if they will hold a charge and test them to see how much they will put out before scraping them. Do you have a battery monitor? Well worth the investment to see what is really going on.

[ckapavik]

I have done a slight load test I guess? I placed the batteries on yesterday and did not connect to power, I was getting a reading of 12.9, then started adding lights and fans as possible and I thought it dropped down to 12.7ish. I might redo this test and record my results properly.

I think one battery may be toast, I will get it tested prior to replacing, but it ended up dry. We had just got back from a two week trip with about 10 days on battery power / solar and all was well. I didn't check batteries or anything once getting home and about two weeks later we noticed a sulfur smell. Checked the batteries and one was dry while the other still had some water, still low though. However, it does still hold a charge as it has been off the charger for four days now and is still reading 12.9.

Regardless, sounds like the converter is gone. Will need to get it replaced.

[gator.bigfoot]

If you can get a 5 amp load going you can see how long before the batteries drop below the 50% level. That will let you know what condition the batteries are in. Take a look at the battery manufacturers sheet at what voltage that should be at.

Batteries going dry isn't good. Most likely then you'd want a matched pair. Otherwise one would try to compensate for the other. Those flooded really require monthly maintenance. AGMs are better for that. Or lithium but then you need to make sure they are fully charged before winter or remove them.

[uncle_bob]

Originally Posted by ckapavik

I have done a slight load test I guess? I placed the batteries on yesterday and did not connect to power, I was getting a reading of 12.9, then started adding lights and fans as possible and I thought it dropped down to 12.7ish. I might redo this test and record my results properly.

I think one battery may be toast, I will get it tested prior to replacing, but it ended up dry. We had just got back from a two week trip with about 10 days on battery power / solar and all was well. I didn't check batteries or anything once getting home and about two weeks later we noticed a sulfur smell. Checked the batteries and one was dry while the other still had some water, still low though. However, it does still hold a charge as it has been off the charger for four days now and is still reading 12.9.

Regardless, sounds like the converter is gone. Will need to get it replaced.

Hi

One battery completely dry and the other almost dry is not good at all. If you checked the at some point in the last month or three ( ... and they did not need filling ....) it's very much a bad sign.

Batteries can go dry for a couple of reasons. One is a converter / charger that is putting out 17V. This can also damage various items on the trailer ( like LED lights ... I have data on this ....). Another reason is a shorted cell in the battery. ( = a failed battery).

Given that Costco will likely sell you a pair of new deep cycle RV flooded batteries for < $80 on sale, I would not bother with these batteries. I'd replace them and move on.

The converter is relatively easy to check. Power things up and measure the output with your multimeter. If it's a stock AS unit and it reads anything over 14V, replace it.

While you are at it, if you don't have an EMS in or on your trailer, this might be a good time to get one. Converters are often the first thing to die when there is an issue. If you have killed one, there's no reason to believe it won't happen again ...

Bob

[ckapavik]

Just noticed I never replied. Thank you all for your help.

I ended up changing out the converter with one suggested by Best Converters, PD4655L/MBA (Wildkat). This solved my issues and everything has been working fine since the switch. I also just went ahead and switched out the batteries as I would rather have the peace of mind that everything is back to good standing, rather than deal with any potential issues at a later point.

I do have a Southwire 44260 Surge Guard. I will look at potentially replacing this too to prevent any issues in the future with something a bit more robust. We rarely camp with electricity but we did the campground prior to the issue so I suppose this could have caused the issue? Not sure, but at least it is resolved.

Regardless, thank you all for your help.

Cole