FYI Managing EMS (power use)

[Neal]

After the saga of my OASIS electrical issues and a failed relay I learned quite a bit about the electrical demands. Last April when returning home i stayed in a CG where the breaker was overheating because it was hot and I was running everything including laundry. Wasn't their fault, I was stressing the 50A shore power supply.

We have a nice EMS system that will load shed based on demand. But can you be smarter than your EMS to avoid a load shed? For example, those with 3 air conditioners, do you want to ensure they keep running and not load shed when you fire up the Microwave or run laundry? For those of us running 2 or 3 A/C's do we want to be smart and keep those running to maintain temps when it's super hot?

Granted, EMS is automatic but the one item that really stands out to me is the OASIS electric heating elements, i.e. when we have AC I/II ON. When that green light comes on to heat water that is an instant ~22 AMP hit on your shore power demand. Maybe more, maybe slightly less. That's nearly HALF of your electrical load. What I do such as I'm doing right now with both AC's running and laundry going and I just used the Microwave for lunch is that knowing I'm going to load up the demand I turned OASIS electric burners OFF and turned the Diesel burner ON. This frees up ~22A of your power so EMS doesn't have to load shed and you can use your diesel burner for "free" heat (when it comes to AMPS) and more effective heating. On top of that, we don't want diesel sitting in lines or nozzles gumming up, keep that stuff moving every now and then.

So that's my tip, valid or not I welcome others to chime in with your opinions. But I think knowing your OASIS electric element demand and realize when your coach EMS is load shedding (which it will tell you if you go view the display) you can help keep things cooler in your coach when Air Conditioning is vital.

 

[Sealyn]

If on 50 amp shore, that is 50 amps per leg, Oasis AC 1&2 are on different legs so only 11 amp draw each, less than 1/4 of the available 50 amp per leg.

 

[Neal]

It was interesting when I had the breaker issue the CG owner/maintenance guy said I was probably pulling 45A, which may have been true. That was also before my OASIS was fixed.

 

[Sealyn]

It was interesting when I had the breaker issue the CG owner/maintenance guy said I was probably pulling 45A, which may have been true. That was also before my OASIS was fixed.

45 amps on one leg of a worn out 50 amp 2 pole breaker is probably a bit much.

 

[Joe Hogan]

Sometimes it is easier to think in Watts rather than Amps.

For example, 20-amp service requires 2,400 watts (20 amps times 120 watts), and 30-amp service needs 1-1/2 times as much power (3,600 watts, or 30 amps times 120 watts). For 50-amp service, however, the potential amount of power used – 12,000 watts, or 50 amps times 240 volts – represents more than three times as much possible demand as 30-amp service.

 

[Neal]

Regardless of the math, if you want to avoid EMS load sheds the easy item to save AMPS or WATTS is to kill the OASIS electric elements and use the diesel burner.

 

[svoshop]

Regardless of the math, if you want to avoid EMS load sheds the easy item to save AMPS or WATTS is to kill the OASIS electric elements and use the diesel burner.

I have little experience with the Oasis system. But this makes solid sense. I also like the idea of keeping diesel fresh(er) in the system that supplies heat to the elements. I would imagine the components of the Oasis system would not be adversely affected by quality diesel additives that were put into the fuel system as preventative maintenance, and may help keep things clean there too!

I have not had a coach that had the ability to demand such a load, and this insight is helpful. In my current Seneca, I have a tank to heat water and I keep the heating element on, and I have run both AC units also, but there is no "Surge" in that heating element like I understand the Oasis to demand.

Mike

 

[Sealyn]

I have little experience with the Oasis system. But this makes solid sense. I also like the idea of keeping diesel fresh(er) in the system that supplies heat to the elements. I would imagine the components of the Oasis system would not be adversely affected by quality diesel additives that were put into the fuel system as preventative maintenance, and may help keep things clean there too!

I have not had a coach that had the ability to demand such a load, and this insight is helpful. In my current Seneca, I have a tank to heat water and I keep the heating element on, and I have run both AC units also, but there is no "Surge" in that heating element like I understand the Oasis to demand.

Mike

Not sure what you mean by "surge", but simply the Oasis has 2 1500 watt elements which draw about 12 amps each.

 

[svoshop]

Not sure what you mean by "surge", but simply the Oasis has 2 1500 watt elements which draw about 12 amps each.

I guess it is my understanding that draw the max amount of amps when starting up? Like an AC unit. Once in operation, the load lessens... Maybe I understand it incorrectly.

 

[Neal]

I think it's an instant hit of 12 AMPS per line and sustains that until OASIS turns it off when no longer needed.