More electrical systems questions

Hi All,
My motorhome's house power was completely out this morning because I left a light on from last trip (I didn't plug into a home extension cord as normal - I got lazy).  Upon investigating it I notice that the Aux Battery switch was off (I think some people call this a "salesman switch").  I assume this is standard functionality to protect appliances?  Is it the inverter/charger that trips this?  I rarely turn this switch off so I assume it switched to off automatically.

Also, I plugged into my home using an extension cord.  All looked normal for some time.  When I looked again I noticed the RV's power was out (by looking at the control monitor).  I had tripped my house's circuit breaker.  I had the furnace running at the time.  For those of you who connect at home using an extension cord - what amperage of a circuit breaker do you normally use? I believe my home's breaker is 20amp.

2003 Fleetwood Bounder 37U DP

I am still newbie-ish when it comes to RV's and I am a novice with electrical stuff. 

Thanks in advance and thanks for this forum!

Depends on the house wiring...It could be 15 or 20 amps.

It also depends on what else in the house shares that circuit.

I would hit the RV and shut off anything you don't need running. The converter may suck up a lot of amps recharging the batteries. If your running the reefer it also will use a fair bit of power.

You can forget trying to run electric heating. (Gas should be OK as long as the batteries are charged)

I have a dedicated 20 amp plug that I installed for another project. But I added a dedicated 30 service for the RV. That way we can run anything in the RV as needed.

I believe that switch works a latching relay.  When the voltage falls below a certain point the relay opens.

Thank you Gizzmo and Old Crow!

thelazyl said:

Hi All,
My motorhome's house power was completely out this morning because I left a light on from last trip (I didn't plug into a home extension cord as normal - I got lazy).  Upon investigating it I notice that the Aux Battery switch was off (I think some people call this a "salesman switch").  I assume this is standard functionality to protect appliances?  Is it the inverter/charger that trips this?  I rarely turn this switch off so I assume it switched to off automatically.

Also, I plugged into my home using an extension cord.  All looked normal for some time.  When I looked again I noticed the RV's power was out (by looking at the control monitor).  I had tripped my house's circuit breaker.  I had the furnace running at the time.  For those of you who connect at home using an extension cord - what amperage of a circuit breaker do you normally use? I believe my home's breaker is 20amp.

2003 Fleetwood Bounder 37U DP

I am still newbie-ish when it comes to RV's and I am a novice with electrical stuff. 

Thanks in advance and thanks for this forum!

Click to expand...

The "Salesman switch is a battery disconnect switch. there is nothing automatic about it. Someone has to turn it on and off.  It disconnects all but a few parasedic 12 volt items. Co monitor, radio. Remote controls. It has nothing to do with appliances.


When plugged in at home try not to use a GFI protected circuit. If you do, trip all GFIs in you RV. 2 gfi's in series don't play nice. 20 is the correct amps to plug into.

Thank you Cavie!

Far as I know the only thing that operates the "Switch" is the physical switch. NO automatic anyting. Some latching relays may drop out when power is lost but the one that's on MY RV uses a magnetic latch. not an electromagnet but a permanent magnet.

BUT I have accidently hit the switches in that area several times  In fact I wound up putting a protector on that switch so I'd not accidently hit it.

When I was an RV tech, I had a brand new coach towed into the shop with dead batteries.  In the end it turned out that the couple had spent a night out of the RV.  While the wife returned to get her bed clothes for the evening, she noticed the 2 red LEDs in the stairwell and helpfully hit the switches to turn them off.  Husband had no idea there was even such a thing as battery disconnect switches, and since the coach was new, had it towed to the dealer.
I walked up to the coach while the tow driver was still disconnecting, noticed the lights were out, hit the switches and magically restored power to everything.  Didn't have the heart to charge the guy, but he tipped me a $20 for hooking the driveline back up.

The one time I let the batteries in my '89 P30 coach fall to near zero, the switches dropped offline and would't reset until I put a charger on the batteries, even after I plugged the coach to shore power.

The "Salesman switch is a battery disconnect switch. there is nothing automatic about it. Someone has to turn it on and off.  It disconnects all but a few parasedic 12 volt items. Co monitor, radio. Remote controls. It has nothing to do with appliances.

That's not true with my MH.  I have 2 switches and when they are OFF, nothing 12 volt works, including the radio, refer, steps, etc.

On my current coach my Magnum Inverter/Charger has a setting to limit the 120 volt current the charger can pull to charge the batteries. When using a 20 amp plug I adjust this setting so the charger doesn't kick the house breaker. This is only a problem if the batteries are low and the charger wants to bulk charge at it's maximum rate. So in the OP's case since his batteries were low his charger could be drawing more that the 15 or 20 amps his house provided not to mention any other stuff that was running.

Most appliances in an RV use 12v power for their circuit boards, so total loss of 12v knocks out almost everything.  Including the a/c if it has a wall thermostat, the fridge, water heater and furnace.

cavie said:

  It disconnects all but a few parasedic 12 volt items. Co monitor, radio. Remote controls. It has nothing to do with appliances.

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What do you call appliances.. I will give you a list and a comment on each
This is from MY RV by the way
Television Radio. Computers. and the like:  You are correct
Microwave. LIkewise
Front A/C (Coleman with "local" or Ceiling controls) again you are correct
Rear A/C Advent air with adapt-a-kit to Carrier controls needs 12 volt or nothing the 12 volts run the controls
(Most A/C's with WALL MOUNTED thermostats use 12 volts.. Carrier .. Well not technically a wall mount but uses 12 volt non the less)
Furnace 12 volt appliance
Water heater.. I think Surburan's will work on electric w/o 12 volts (not sure) or at least some will.  Hott-Rod equipped (Propane only converted to dual power) Do not use 12 volts
But DSI Propane water heaters and Atwood' be they on Gas or electric need 12 volts.

Refrigerator is also a DSI propane and 12 volt controlled electric. NO 12 volts No opeartion

ENGEL Chest Freezer.. 12 volt (or 120 volt but not both at the same time, Different power cords)
Mine runs on 12  3 amps of 12 so why play musical cords???

I also have an electric carving knife.. 12 volts (At least I think that is what I modified to run on 12 volts) Used to use batteries. (D-Cell type)

So several appliances need 12 volts to operate.

But then  The only time I hit the cut off is when I need to change batteries or when getting propane. .easiest way to shut down ALL DSI stuff. (Direct Spark Ignition).

All, thank you for your input it is helpful for me to understand my coach.  I have 1 remaining question as I couldn't find the answer in my manuals.  I've attached a picture of my control panel where the coach is hooked up to my house.  I have a 30amp adapter which has another adapter which fits my extension cord.  I believe this "other adapter" is a 30 to 20amp. This is on my coach.

In the picture it reads 18 amps and you'll see where I selected the 20amp service type.  I had no appliances on at this time.  It was down to 3 amps by this morning.  I assume, therefore (??) that the charger/inverter will "pull" more amps if it thinks the house batteries need a charge, and will reduce the number as the batteries charge??  This is the on explanation that makes sense to my novice brain.

This is what I DID learn over the weekend:  The house breaker for which the extension cord is plugged into is a 20amp breaker.  The orange extension cord I USED to use outside is rated at a lower amperage (15 amp) which explains why that cord got worm when I originally plugged in and the monitor showed 18amps. I replaced the cord immediately with a yellow outside cord with a higher amp rating. Going forward: (1) I will leave the coach plugged in each time it is parked at home, (2) I will always use the yellow extension cord and (3) will bring in an electrician to install a 30amp thing for me to plug into.

Thanks again everyone!

(3) will bring in an electrician to install a 30amp thing for me to plug into.

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What are you going to do with the RV at home? If you are only using the power to keep the batteries charged up then the 20 amp outlet will do just fine. If you are planning on having someone occupy the RV at your house then you will probably need 30 amp outlet. If you do hire an electrician make absolutely certain he understands the fact that you need a 30 amp 120 volt outlet, not a 30 amp 240 volt outlet or you will fry a lot of your electronics. There are no 240 volt appliances in the RV. The outlet you want looks like this:

https://www.amazon.com/BougeRV-Receptacle-Electrical-Adapter-Handle/dp/B076N3YYVK/ref=sr_1_1_sspa?crid=U5FNML3YFEMV&keywords=30+amp+rv+receptacle&qid=1555347676&s=gateway&sprefix=30+amp+%2Caps%2C180&sr=8-1-spons&psc=1

X's 2 on making sure the 30 amp is wired for 120 volts...It's not a common thing outside of RV use.

I would vote for installing the 30 amp plug. We have used ours twice as a "Guest room" and we also ended up using it while having our main part of the house ceiling repaired and painted.

Great points!

At this time our sole purpose is to keep the house batteries charged in between trips.  We do have growing grandkids which means the RV could eventually be used as overflow accommodations.  I will use the existing outlet for now, and then later hire a professional electrician to properly setup a 30amp outlet suitable for an RV.

Two thigns since it look like you are figuring it out.

1: Home Depot. Lowes and Sears/K-Mart all sell 12 ga extenion cords. I like them and have some I use for my RV.  12ga may also warm slightly at 20 amps but not alarmingly so.. Sears/K-Mart sell a model with a push button on the outlet. this is what I like the adapter you plug into it is less likely to detach from the 15 amp rated cord (they still rate 'em 15 even though they are 12ga)


The second.. You said

I assume, therefore (??) that the charger/inverter will "pull" more amps if it thinks the house batteries need a charge, and will reduce the number as the batteries charge??  This is the on explanation that makes sense to my novice brain.[/quote}

You nailed it. that is exactly correct. Could not have said it better myself.

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thelazyl said:

Great points!

At this time our sole purpose is to keep the house batteries charged in between trips.  We do have growing grandkids which means the RV could eventually be used as overflow accommodations.  I will use the existing outlet for now, and then later hire a professional electrician to properly setup a 30amp outlet suitable for an RV.

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I would suggest going to Home Depot and getting a 12 gauge extension cord as short as you can get away with. Too small of a wire gauge or too long of an extension cord will cause the cord to be warm.

It appears that hat you have a 50A rig. When it is time to put in an outlet it might make more sense to make it 50A. Cost is quite similar and, even if your rig is 30A, the next one may make use of a 50 A's service.

Ernie

Ernie n Tara said:

It appears that hat you have a 50A rig. When it is time to put in an outlet it might make more sense to make it 50A. Cost is quite similar and, even if your rig is 30A, the next one may make use of a 50 A's service.

Ernie

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Good point...X's 2 on what Ernie said