Tom is Officially Flummoxed - Need Second Opinion

[GENESIS]

You know......I believe I know my way around DC and AC circuits/voltage/wiring/whatever, but my new 337RLS has beaten me to a pulp. So bad that I had to resort to two Scotch's last night - straight even!!!!

So here's what's going on. A couple of weeks after we got the RV home, I ran a dedicated AC feed to a receptacle so I could plug in my shore power (sorry for the terminology - I'm a boater) four prong plug. The receptacle was metered and it showed 121 point something volts at 50 amps - perfect. So I plug in my shore power (SP) cord and meter it at the other end of the cable. Sho 'nuff, 120V @ 50amps. So I plug it in.

Now......when we did the PDI, we don't recall being told that the master 50 amp breaker needs to be in OFF position before connecting to SP. However, in reading through the RV manual it says to do this. Anyhow......

We go into the RV, start turning stuff on and wha-LA! Everything seems to be working fine except the frig which we finally solved. After my victory dance, we turned everything off, turned the battery disconnect to the OFF position and left the SP connected. Couple of days later a friend comes over, wants to see inside, we hit a couple of light switches and......nothing. Ruh-roh.

The next day I put my meter on the battery and it's showing south of 6 volts, so I put my faster charge battery charger on it. But I'm puzzled because I would've thought the SP connection would've charged the battery. Then I think it must have something to do with the batt disconnect being in the off position. By now I've been lectured by my wife that I didn't throw the master breaker in the OFF position prior to SP connection. So I disconnect SP, throw all the breakers into the OFF position and go off to my crown moulding installation project.

The next morning I check the battery and it's fully charged, however I swap out the big charger for my Battery Tender and it's showing "storage" - good. So I go to the SP cord, plug it in to the RV connector, go inside the RV, throw the master breaker to ON, then all of the other breakers to ON. Hit the lights - fine. Slides work fine. A/C works fine. After I do another victory dance we leave the A/C on and the slides out and the Battery Tender connected.

Yesterday, I wanted to be dang sure everything was hunky-dory, so I opened the RV up and the frig was beeping and no A/C was running. I hit a slide retract switch and nothing (but oddly the Fantastic Fan vent lid opened up). I tried the awning - nothing. Sonafabitch.......

OK Tom....back to the basics: meter the SP power receptacle - checks good. Meter the input to the RV - checks good. Go to the battery, the Tender says "Charging" and is warm to the touch (that's rare). So I decided to dive in to the load center. I measure the SP input to the master breaker and I get 121 volts @ 50 amps to both terminals of the breaker. I turn the master breaker ON and nuthin'. Then I check the DC side (where the plastic fuses are) and I'm getting 11V DC. I go back to the battery and check for DC at the buss bars. Once again - checks good. I've metered everything except my brain and everything checks out good. I'm beaten. So I shut everything down - breakers all OFF. I'm sitting on the back porch noodling through everything I can think of. After two the two aforementioned Scotch's, I'm wondering if there's something between the SP RV receptacle and the load center that prevents SP hook up with the master breaker ON. So I disconnect SP at the RV side wait a few minutes, plug it back in, throw the master breaker ON and.........I'll be a son-of-a-gun - everything works. The wife comes out and asks what I did and I said I haven't a dam clue. So we leave the A/C on and the ceiling lights on.

This morning I started towards the RV and I could swear I heard it laughing at me. I open the door and nothing is on. SP is connected. I look at the Tender, the charging light is lit and it's warm.

I give up...........

Tom

[offtohavasu]

Let me break it down to what I think you're getting at, so we can make sure we give the correct advice.

Battery Switch is on (not is disconnected position)
Plugged in to 50 amp 240v service (two legs of 50 amp 120)
All 120v receptacles and appliances are working
You only have 12v power AFTER charging with external charger

If this is correct, we can proceed to the next options

I believe there's directly on the converter, check that.
Make sure you're getting voltage out of the converter to the battery. You can do this by disconnecting the power leads from the battery and see if there's voltage on the wires.

[Paul & Deb]

Okay, here goes ......... I have no freakin' idea what the heck you are talking about! How's that for help.

I need clarification, are you saying you added a second receptacle to plug your shorepower line into?

And you're saying the manual says we're supposed to shut off the 50amp breaker in the fuse panel before we hook up to shorepower?

[GENESIS]

Dayyyyyum......why didn't I think of that?

Your breakdown is partially correct.

- I have in my shop breaker box a 120V 50 amp breaker
- That wire is a direct feed to a 50 amp 4-prong receptacle. Ground wire (bare copper) to the "green" terminal. White (neutral) to the "white" terminal (bottom prong). Black wire jumpered to both right & left terminals (and subsequent prongs)
- Receptacle meters 120V @ 50 amps
- The RV breaker box SP feed meters 120V @ 50 amps to both sides of master breaker.
- The DC side of the load center meters essentially 12V

Yes.....the bottom line is that the RV appears to be only working off the battery.

Are you saying (implying) that if the converter is not working, it matters not that you have 120v coming in to the RV?? I'm seriously trying to understand this. However the (electrical) logic evades me. In my way of thinking, without the presence of 120V supply to the RV (i.e. shore power), the converter takes the battery DC voltage and converts it to 110/120V. When SP is connected (detected), the system should bypass the converter and send the 110/120V to the RV's system.

FWIW......I had a question about supplying either 120 or 240 out of my shop load center to the dedicated RV SP. I called the dealer, spoke to a tech and he said that all the units are hooked up to 120V during PDI. So that's what I ran with.

Your reply Curtis is greatly appreciated. As for Poppy's........well, I'll leave that alone. HAHAHAHAHAHA. Just kidding Poppy. But yes - it say right dare in da manwell - turn the Master Breaker off before connecting RV to shore power. When the wife told me that, I said that can't be right because it shouldn't matter. In return I got the manual shoved.....uh.....uh......in my face.

Off to get my Fluke.

Tom

[JCR GD]

Are you saying (implying) that if the converter is not working, it matters not that you have 120v coming in to the RV?? I'm seriously trying to understand this. However the (electrical) logic evades me. In my way of thinking, without the presence of 120V supply to the RV (i.e. shore power), the converter takes the battery DC voltage and converts it to 110/120V. When SP is connected (detected), the system should bypass the converter and send the 110/120V to the RV's system.

But yes - it say right dare in da manwell - turn the Master Breaker off before connecting RV to shore power. When the wife told me that, I said that can't be right because it shouldn't matter. In return I got the manual shoved.....uh.....uh......in my face.

Off to get my Fluke.

Tom

So that is part of the problem... it is a converter not an inverter. It does not provide 120v when shore power is off. It only provides 12v to power 12v stuff and charge the battery.

My guess on the breaker needing to be OFF is just for the initial spike when plugging in, not to be left off.

[offtohavasu]

So what happens with the converter is is it will supply and charge the 12v system. So when plugged in, and the battery disconnect in the On/Connected position, then the converter charges the battery, which in turns supplies power to the coach. If you're getting 12V power with the battery and it's draining while the disconnect is in the on position and 120V is supplied, then we have to check the converter to make sure the power is making it to the battery. It seems that it is not.

Now for your receptacle issue. What you have wired up is basically what you would have if you used a 30 amp adapter. Where you may/will run in to an issue is if you use the current setup with your all your a/c's on, refrigerator on ac, etc. The purpose of the split 50 amps (240v) is to split the load. I hope that makes sense.

[offtohavasu]

Sorry, I missed the other part, that Jim filled it. The 12v system, in factory form, will not supply 120v back to the outlets. That is only supplied with shore power. You will need to have an inverter, as Jim mentioned, to accomplish that.

[Paul & Deb]

Okay, I get it now. The new receptacle you installed was on your HOUSE not your RV! I get it.

As far as turning off the master breaker, that's gotta be CYA BS because I have never, ever done that in any previous RV!

I'll leave now and let the electrical gurus finish with the pertinent advise.

Back to watching The Walking Dead and drinking my Corona

[Cate&Rob]

Just catching up to this thread . . . interesting discussion ! Tom, you do have an interesting way of explaining things .

You mention several times that you measure 120VAC @ 50 amps . . . I expect that you are actually just measuring voltage, not amperage? If your rig is drawing 50 amps, there is something else going on. Splitting a 120VAC 50A supply into two legs is an unusual configuration but should work as Curtis says.

Part of the confusion is that what we boaters would call a "battery charger", RVers call a "converter". Not to be confused with an "inverter".
As a simple test, with shore power plugged in (and no auxiliary battery charger connected) what is the voltage across the battery posts. If this is less than about 14V, your battery charger (converter) is not working.

RV appliances that run on 120VAC (fridge/AC/water heater) have 12VDC control circuits powered by the RV battery. You can have 120VAC power to these devices, but they still won't work if you don't have 12VDC to the control circuits. Back to a dead battery because the battery charger (converter) is not working.

Rob

[charliem]

I won't wade into what your electrical issue is but I will comment on the circuit breaker issue. It is recommended that the circuit breaker on the shore power source be turned "off" prior to plugging in the cord from the trailer. This prevents arcing of the contacts as the plug is inserted into the receptical. Routinely turning "off" the circuit breakers on the trailer electrical panel is not necessary.