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Topic: Need shore power explained (Read 1219 times) previous topic - next topic

Need shore power explained

I know a little, enough to be dangerous as the saying goes.  What I don't understand, the 50 amp plug has two 120 legs coming in, so I'd assume that each leg runs a portion of the coach, yet hooking up to 120 (via an adapter), the whole coach still has power, (albeit not enough.)  So how does it handle the two 120 legs from the 50 amp plug?  Is there a magic box that combines it into one leg???  OR, more likely, a magic box that connects the 120 into two sides of the coach.  Either way, there must be a magic box?  :-\
1996 U270
Build #4846

Re: Need shore power explained

Reply #1 –
Quote
OR, more likely, a magic box that connects the 120 into two sides of the coach.  Either way, there must be a magic box?

In order to plug into the 30 amp receptacle we have to use a 30 amp adapter on the 50 amp cable. 
Inside the adapter (The magic Box) the one 120v circuit hot wire is connected to both hot wires of the 50 amp cable and everything works. 
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Need shore power explained

Reply #2 –
 ;D And the reason that it all works is that; our motor coaches do not have any appliances that require 220 volts a.c.,  In your home where we use 220 volts for a stove or a clothes dryer each 110 volt leg attaches to a different buss bar in the circuit breaker box... thus each leg supplies 1/2 the voltage to the 220 volt appliance supplied from different sources...  :D ??? ??? ???  p.s. you can get 50 amps from a 110 volt supply box as long as the supply wire to that box is of sufficient  size to carry that load..  I THINK !!!!!!! Gerry
The selected media item is not currently available.
Gerry & Brenda
CHARLOTTE HARBOR, FL
1994 Grand Villa - # 4466
U300 Unihome - 6V92 Detroit
4 speed Allison - Jake Brake

Re: Need shore power explained

Reply #3 –
So to be clear - when we plug into a 50 amp outlet, assuming it's been wire correctly, we are plugging into two legs of 110, and each leg runs part of the coach.  But if we adapt it down to a 30 amp plug, or smaller, the adapter is sending just one leg of 110, but the adapter sends it to both parts in the coach.  This now makes sense to me, so PLEASE even if you have to lie, tell me it's correct!  Then we'll go onto phase 2 of what I'm working toward.
1996 U270
Build #4846

Re: Need shore power explained

Reply #4 –
Quote
PLEASE even if you have to lie, tell me it's correct!

You are correct. (No Lie)
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Need shore power explained

Reply #5 –
That would be absolutely correct!

Quote
old_nodaker wrote:

Member old_nodaker replied to the topic 'Need shore power explained' on the 'Foretravel Tech Talk' Board.

So to be clear - when we plug into a 50 amp outlet, assuming it's been wire correctly, we are plugging into two legs of 110, and each leg runs part of the coach. But if we adapt it down to a 30 amp plug, or smaller, the adapter is sending just one leg of 110, but the adapter sends it to both parts in the coach. This now makes sense to me, so PLEASE even if you have to lie, tell me it's correct! Then we'll go onto phase 2 of what I'm working toward. 1996 U270

The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Need shore power explained

Reply #6 –
I suggest that you take a look at your owners manual and pull out the schematic for the 110volt wiring and while you are at it, take it to Kinko's and copy parts of it to a bigger scale and make a few extra copies.  They come in real handy when troubleshooting.

It will shed some light on the situation and allow you to become much more familiar with the entire system.  Worth the time it will take.
JON TWORK KB8RSA
Full Time RVer (10+ Years) & Dedicated Boondocker
Retired, Unemployed, Homeless Transients
1996 Foretravel U270-36 w/24' Timberwolf Trailer
I firmly believe that tomorrow holds the possibility for new technologies, astounding discoveries, and a reprieve from my remaining obligations.
Welcome to WeRV2 (Under Construction)
Find Jon: Via Satellite Tracker Datastorm Users
The Second Amendment is in place in case they ignore the others.

Re: Need shore power explained

Reply #7 –
An excellent idea, cause I sure can't figure it out by looking at the coach.  Actually I can do it right here on my scanner.  I've been working my way back into some of the older posts, bad idea, just brings up more questions.  Right now I'm needing to get into the inverter side of things so I can wire the new household fridge I'm installing.  I don't want to connect into the existing set of plug-ins cause they already seem to be an overload situation.  The GFI in the bathroom has popped several times for no apparent reason.  Is the GFI being used as a overload breaker?  Is everything hooked up to it?  What happens when battery voltage gets to low?  Is there a automatic shut off?  If so, does it have to be manually reset?

I realize there isn't an infinite amount of power available from the inverter.  I did run the fridge off an extension cord plugged into the bathroom for 5 hours today.  It pulled the batteries down to 12.25 volts, with nothing else running.  I have no idea how old the batteries are.  It maintained the previously cooled fridge at 0 in the freezer and 35 in the fridge. 
1996 U270
Build #4846

Re: Need shore power explained

Reply #8 –
I suggest that you purchase a separate inverter for just the job of running the refrigerator and make sure that it is adequate for continued use and not a lesser duty cycle.

This will give you redundancy in the event one or the other fail.

The wiring of it will be simpler too without endangering the integrity of the existing system.

I would image that you have just two coach batteries and suggest that you improve that number to three for more capacity in the event you need it.

If your current 130 amp alternator fails, I would move up to a 160amp unit.
JON TWORK KB8RSA
Full Time RVer (10+ Years) & Dedicated Boondocker
Retired, Unemployed, Homeless Transients
1996 Foretravel U270-36 w/24' Timberwolf Trailer
I firmly believe that tomorrow holds the possibility for new technologies, astounding discoveries, and a reprieve from my remaining obligations.
Welcome to WeRV2 (Under Construction)
Find Jon: Via Satellite Tracker Datastorm Users
The Second Amendment is in place in case they ignore the others.

Re: Need shore power explained

Reply #9 –
I've thought about a third battery, it would appear with a little reinforcing one could mount on the shelf above the two.  I hadn't thought about another inverter, but certainly worth thinking about also.  I already have the 160 amp alternator, but just reading through a old Motorcade magazine I found in the coach, there's an article advising turning the boost on and running the generator to charge all the batteries if they're low,  rather than making the alternator do it.
1996 U270
Build #4846

Re: Need shore power explained

Reply #10 –
I currently have a third battery on the top shelf.

I put a couple of 2x4 pieces on top of the other two batteries in case of a collapse.

It has been working for five years without a problem. > > >
JON TWORK KB8RSA
Full Time RVer (10+ Years) & Dedicated Boondocker
Retired, Unemployed, Homeless Transients
1996 Foretravel U270-36 w/24' Timberwolf Trailer
I firmly believe that tomorrow holds the possibility for new technologies, astounding discoveries, and a reprieve from my remaining obligations.
Welcome to WeRV2 (Under Construction)
Find Jon: Via Satellite Tracker Datastorm Users
The Second Amendment is in place in case they ignore the others.

Re: Need shore power explained

Reply #11 –
But I suppose they should all be new/same age, right?  I discovered I mis-spoke in my previous post.  I do only have the 130 amp alternator, its the isolator that's 160.
1996 U270
Build #4846