Losing both 12V and shore power

[RickL]

I’m sure that somehow these are related but I’m so deep in diagnosing that I’m thinking I can’t see the forest from the trees.

I have a permanent surge protector and no factory generator.


First, I have been losing shore power intermittently the last few days. I was thinking the reason was I was running 2 a/c units on a 30 amp and the outside temp was very warm. When the shore power would drop out I would still have 12V in the trailer.

I moved today and am now hooked up to 50 amp service. Hot and humid so I cranked up the 3 a/c units. After about 30 minutes the shore power went out, the pedestal breaker was still ok. But when I lost shore power I also lost 12V. The control panel went dark. Then the power came back on and so did the control panel.

I have checked voltage across every breaker and i have battery voltage on both sides of the breakers. I also checked every fuse and those are all good.

Im thinking I have two issues. One is on the 12V side and the other is on the 120V side. Any input as to why I would be losing 12v would be appreciated. Maybe I’m just overthinking everything and am missing some easy.

now the batteries are not charging so I’m thinking once I figure that out I may be on my way to figuring out the 12V issue. The batteries still have 85% charge (I have a Victron monitor)

 

[RickL]

Ok, I got the batteries charging. Not sure why I had voltage across each breaker but the one breaker needed to be reset.

Now onto to why I can’t run at least 2 a/c units without having the system cycle.

 

[emery395]

I am a novice rver but something similar happened to me a few weeks ago. Ac power went out and12v was very weak. Turned out converter was bad and not changing battery. Putting car charger on battery solved issue until I could get new converter

still cant explain why weak battery affects ac shore power

 

[mlpeloquin]

This is one place you may not have checked. If you have a power cord real, you may have loose connections inside the real. You will have to unplug from the pedestal and pull the entire cable out of the real. This will expose the hatch that is held on by screws. Open it and check to make sure that the connections are not loose. If you have the generator prep package, again unplug and check the connections in the transfer switch.

 

[danemayer]

So your Oshkosh probably has Generator Prep even though no generator. And your 2018 probably has a KIB Control Panel. And you have the PCS energy management system.

If the manual reset 12V DC circuit breaker was tripped, there was no power from the batteries going to the fuse box. And then when you also lost 120V AC power, the Power Converter lost its 120V AC power source. So it wasn't producing any 12V DC. With no 12V DC from either the Power Converter or the batteries, you probably lost power to the KIB Control Panel and control boards, shutting down all of your 12V DC lights and appliances, along with thermostats.

All that said, you need to find out why you're losing shore power (presumably inside the coach, not at the pedestal). My guess is that you're dropping below 105V on L1 on the shore power input to the automatic transfer switch that's part of generator prep. That will cause the contactors in the transfer switch to drop, shutting off both AC power legs.

Also, your surge protector, if actually an EMS that protects against low voltage, could be shutting power off if the pedestal drops below 105V. But there should be an error code that indicates it shut down due to a low voltage condition. And when voltage goes back to normal, it should come back on automatically.

Another possible problem area is at the powered cord reel.

And of course when it's hot and everyone in the park has 2 or 3 air conditioners running, you can have a brownout leading to a shutdown.

There's more information you may find helpful in our owner-written Electrical User Guide.

 

[RickL]

Dan, I think you hit the nail on the head with your explanation. I pulled the plug at the pedestal and found corrosion on the blades. Should have been checking these as I spent the last 3 1/2 months on 30 amp service. Every time it rained or was damp I was having issues - water would get between the 50 amp plug and the adapter, even though they were as tight as you could get them. Found it by accident as I was becoming frustrated with the issue, grabbed the adapter and the 50 cord to check and water leaked out. So now I am going to wrap that connection in plastic to keep the water off when I use the adapter.

That at all being said I cleaned the blades and all seems to be working fine. Just never fun when the heat index is over 100 degrees.

 

[danemayer]

Just never fun when the heat index is over 100 degrees.

You could always join us in the Colorado mountains. High tomorrow is supposed reach 75.

 

[CoveredWagon]

You could always join us in the Colorado mountains. High tomorrow is supposed reach 75.

I think we should have done that. Left SD for WI,where it's been a dress rehersal for he77 ��

 

[wdk450]

Dan, I think you hit the nail on the head with your explanation. I pulled the plug at the pedestal and found corrosion on the blades. Should have been checking these as I spent the last 3 1/2 months on 30 amp service. Every time it rained or was damp I was having issues - water would get between the 50 amp plug and the adapter, even though they were as tight as you could get them. Found it by accident as I was becoming frustrated with the issue, grabbed the adapter and the 50 cord to check and water leaked out. So now I am going to wrap that connection in plastic to keep the water off when I use the adapter.

That at all being said I cleaned the blades and all seems to be working fine. Just never fun when the heat index is over 100 degrees.

Corrosion on the blades (usually on the 30 amp plug) can be caused by unknowingly plugging into a bad campground 30 amp outlet, even for just 1 night. You pretty much cannot see if the female 30 amp blades are corroded from the outside. This is a prevalent "virus" in the RV rigs and campgrounds community. Your newly corroded male plug prongs can cause corrosion to start in the next female outlet it is plugged into by generating heat under heavy current loads. I personally spray my shorepower connections (plug, outlet, RV inlet plug and socket) with Caig DeOxIt contact cleaner/restorer spray with every setup connection.