50 amp MH on 30 amp shorepower - run W/D?

[larrymo]

For those of you whose coach is wired for 50 amp service, but for whatever reason can only hookup to 30 amp shore power FHU at the time, what's your electrical power management challenges when it's hot outside, and want to run the W/D, in particular, stackables?

1. "All electric coaches" - what change / impact does this have over a coach with propane on board?

2. Are you switching from shore power, and running genny?

3. What other electrical systems are you shutting down to run the W/D - microwave / convection, electric water heater / hydronic water heater, etc.?

4. Dropping down from 3 A/C's to 2 A/C's, or all the way from 3 A/C's to 1 A/C?

Additional input welcomed. Thanks in advance.

[larrymo]

I see where this question could apply to the TT folks as well. Your response is welcomed as well.

[CLIFFTALL]

30 amps will only operate two large appliances at most and possibly a few smaller ones. Your EMS will shed loads for you as you go or you could do it manually .

[larrymo]

I've just used an EMS for the first time. It's at the shore power end of the shore power cord, so I'm sure this will not help with auto shutdown of on-board systems.

[sdennislee]

Originally Posted by larrymo

I've just used an EMS for the first time. It's at the shore power end of the shore power cord, so I'm sure this will not help with auto shutdown of on-board systems.

He is talking about onboard EMS not the surge protector plugged in between your power cord and the pedestal. Confusing sometimes with acronyms. In the Navy I learned that we used acronyms to create maximum confusion with minimum letters.

Don't know your coach but most 50 amp coaches have an EMS panel inside that will with priority shed loads when the amp draw hits a certain point. Designed to keep you from overloading the system.

The EMS you plugged in at the pedestal is to prevent issues resulting from bad CG power, i.e. open neutral or ground, under/over voltage, etc.. from impacting your coach

[Elatta1954]

Ok, what is EMS?
I need a cheat sheet for all these acronyms!
EMS =
DW =
So on and so forth

[sdennislee]

Originally Posted by Elatta1954

Ok, what is EMS?

Energy Management System, part of your coach's power distribution system

[chuckftboy]

Originally Posted by Elatta1954

Ok, what is EMS?
I need a cheat sheet for all these acronyms!
EMS =
DW =
So on and so forth

Energy Management System

[sdennislee]

DW = Dear Wife

[Jim T.]

EMS = Energy Management System
Supplied & installed by coach manufacturer during build process. Automatically sheds outlets/appliances as needed.

EMS = Electrical Monitoring System
An add-on by purchaser to protect coach from campground power faults. Shuts off power to entire coach when faults/problems are detected. (See my signature below.)


Jim & Shirley & Abbie (Scottish Terrier)
2013 Newmar Canyon Star 3911
2005 Dodge Grand Caravan - Braun Accessibility Modified Toad
Remco Lube Pump
5 Star Tune
Progressive Industries EMS-HW50C
Coach Net Emergency Road Service

[sdennislee]

Energy Management:
The 50 Amp Smart EMS automatically senses the available power to the motorhome, determining whether it is connected to a 120 Volt AC - 30 Amp shore power source, 50 Amp shore power source or generator source. Depending upon available power, the EMS controls the operation of 6 possible loads as indicated on the distribution panel. These may be any type load, but are typically heavier loads; those whose use can be “postponed until a time when current is available for use. If the available power source is 120 Volt AC - 30 Amp shore power, the EMS attempts to keep the total 120 Volt current draw to less than 30 Amps.

Operation:
If 120 Volt AC is not available at the distribution panel, L1 or L2 outputs, the system shuts itself off. This feature is intended to prevent the system from drawing current from the +12 Volt DC battery supply when not in operation.

When 120 Volt AC power is applied, the system automatically powers up and determines the nature of the power source.
If the generator is running, 120 Volt AC will be present at the distribution panel L1 and L2 inputs. In this mode the energy management feature is disabled and all control relay contacts are closed, energizing all of the controlled loads. The control module sends a signal to the display panel causing the load meter to display actual load current, the GEN SET service indicator to light and all power status indicators to light.

If 120 Volt AC is present at the distribution panel L1 and L2 inputs the system will assume that 120 Volt AC, 30 Amp shore power is available and the energy management feature will be enabled. If only 20 Amp service is available the user must select the 20 AMP service mode by momentarily pressing the 20/30 Amp select switch on the Control Panel. Initially, all relay contacts are closed and the total current is monitored. If the total current should exceed the service limit the system will turn off the rst load in the shedding table, turning the loads off and calculating the amount of current that was removed, which is the value for that load. This value is placed in memory.

If the current remains above the service limit, the system will turn off the next load in the shedding table, again calculating the amount of current that was removed and placing this value, which is the value of that load, in memory.
The system continues to turn off loads until the total current falls below the service limit or all of the six controlled loads have been shed. Through this process the system has “learned” the amount of current each particular load draws. This feature compensates for the differences in current draw over a range of line voltage and ambient temperature, by re-learning the load each time it is turned off or “shed.”

The 50 Amp Smart EMS now waits until the total current is lower than the service limit and enough current is available (as compared with the amount in memory for the last load shed) before turning that load back on. This assures that there is suf cient current to operate the load.

[larrymo]

Thank you so far for the responses. It does help with understanding the advantages of a hard wired / built in EMS, Electrical Power Management System vs one which is simply plugged into the shore power pedestal.


Actually Ellatta, my present interest is in W/D = clothes washer dryer, and better understanding the electrical requirements to operate these units under reduced available pedestal / shore power amperage availability. My question is for the units wired for 50 amps, typically 2, or 3 a/c's - What is the manual electrical power management required to be reduced (electrical load) in order to run the clothes W/D in hot temperatures?

[larrymo]

sdennislee , very good response. So in order of priority, of the 6 electrical loads, what is lost to go from 50 amp pedestal to 30 amp pedestal to be able to run the W/D when it's hot outside?


Also, in what way does this affect the scheduled use of the W/D? I've read the main schedule is load the stackable washer, then leave in the toad for a day of exploring the local hub and spoke system. When arriving back at "home", put the washed clothes into the dryer (those with stackable W/D).

[vsheetz]

When on 30a service:

Set battery charger to low amp setting, such as 5 amp.

Two air conditioners
- or -
One air conditioner plus one other high current draw item (microwave, coffee maker, etc.).

I have not tried laundry along with one air conditioner, although I suspect it would be ok. Instead in such case would do laundry in the evening when air conditioning not in use.

Vince