No DC power- Gen/shore line work fine

[Porto2020]

Hello,

I have a 2020 Porto- was working just fine until the recent hurricane and we were using the generator alot more than usual.

When plugged into shoreline or running generator, everything works perfectly normal.

Tested batteries- showing 13.1V

When the shore line/generator unplugged- EVERYTHING goes out- even the ceiling light and water pump- things that usually run off the coach.

It is behaving like the battery disconnect is off- however i checked it. I'm pretty sure the disconnect switch is working because when the generator is running, i can click off the battery disconnect and it shuts off the generator.

Would appreciate any help. I was looking online and it sounds like an auto reset breaker is tripped but i can't find one looking around the RV or on the wiring diagram.

Thanks!

[creativepart]

Originally Posted by Porto2020

Tested batteries- showing 13.1V

That’s a clear giveaway right there. Your Lead Acid batteries are 12.7 to 12.8 volts at full charge. They will show over 13v when plugged into shore power or when the generator is running. But that’s not your battery voltage that’s the RV’s battery charger voltage.

It’s true that when you unplug the RV to remove the charge from the Converter it can briefly show a higher voltage because it is holding a surface voltage. But that evaporates the second you use the battery even a little.

To adequately test your batteries they need to be at rest. With the RV unplugged, disconnect the positive battery cable and let it sit overnight. Then put a voltage meter on the battery terminals and see what the voltage is. Then you’ll know if your problem is dead batteries or not.

[Morich]

One of the confusing things is the surface voltage as mentioned but then a second item may also be in play.
When you are plugged in, the converter can run the RV items you mention as well as send power to the batteries to be stored.
But when disconnected, you are not getting power from the converter and it sounds like you are not getting power stored back from the batteries.

That makes several things possible!
One the batteries did not store power? Bad batteries?
The path from the batteries back to the load center is different than from the converter to the load center and that path may be bad? Corrosion on cables?

A simple test of another point may help. When you find things not working, try starting the RV engine. When you do this the chassis battery section with engine alternator are connected to the coach section.
When these are connected together, it will make a dead coach battery look alive! It will not change the path from the coach batteries to the fuses!

If you get bad results with only the coach but good results when you have the chassis connected to the coach batteries, it tends to say the coach batteries have a problem!
One horse can't pull the wagon but it moves when you have two horses pulling? That first hosrse may be a problem!

But keep in mind that the batteries are just storage and it is very common for cables to be the real issue so sometimes it is good just to start with cleaning/ checking every cable connection as a shotgun approach.

One reason for going shotgun on this is the cables are such a problem that one might say if they are not dirty today they will be tomorrow!
So cleaning today may not fix today but prevent tomorrow?

There is an item used in industry called "No-Ox-A" (a special grease) which I highly favor using on our RV batteries.
To keep clean connections from getting dirty and corroded, we can clean them well, then cover them with the No-OX to keep air and anything like moisture off the connections. Done right, it can keep things from corroding for years!

I buy it in metal tins and lay it on a trouble light to warm and thin it, so I can paint it on with a small brush!
If it is in a plastic container, setting it in hot water will help it spread better.

[Porto2020]

Thanks to the comments.

Soooo...

I disconnected the batteries to test them. As you implied, the charge after sitting was around 12.7V.

After I plugged them back in....EVERYTHING WORKS AGAIN!

The screws were all tight, but my hypothesis is either there was a bad connection or something "reset" when I disconnected the batteries.

Anyone have an idea why this would happen?

Thanks again!

[Morich]

I don't think of any rest that might work but there are times when we move something just right!
I might suggest checking the cable from the negative post down and behind the batteries to the frame. If that connection gets loose, power is cut.
The problem can be that we forget that end as we don't normally see it! If you moved/wiggled that cable, it may have moved enough to make contact for a while but be waiting to trip you next time!

A point that is often missed is how we check voltages around the batteries. We can do a better job of sorting out and preventing battery problems if we try to stay a little more aware.
We can spot corrosion beginning if we test a touch more carefully. We often test voltage probing right on the battery posts and that DOES tell us something about the battery itself, but we can get good info on the cables and connections if we go a couple easy steps further.
If we test at the posts, then move the probes out past the connections, we get a read on how well those connections are holding up! Probe the post, then move one meter lead out to some clean metal part of the RV, and the other lead out to some point on the positive side that is past the post. There may be a big mega fuse right there in the battery compartment or we have to settle for just probing the cable end itself on the post but if we move even that far and get a significant difference in voltage reading we know we have corrosion beginning at one of those connections!

Kind of like walking in traffic? We can head off some big trouble if we look twice!

[Ray,IN]

Originally Posted by Porto2020

Thanks to the comments.

Soooo...

I disconnected the batteries to test them. As you implied, the charge after sitting was around 12.7V.

After I plugged them back in....EVERYTHING WORKS AGAIN!

The screws were all tight, but my hypothesis is either there was a bad connection or something "reset" when I disconnected the batteries.

Anyone have an idea why this would happen?

Thanks again!

That's a tell-tale sign of a poor connection. That connection can be battery clamp to post, or battery clamp to cable. Testing is the solution, of course buying all new cables is a solution, just more expensive.