Anyone running 3 15M AC's on 50 amp? Follow up added

[Two_Jayhawks]

We have been told we can but not advised. With almost everything else off except residential fridge it is still too close to limits of available juice. Wondering if others do actually run 3 units and how it has worked out. Thanks

We did use all three coolers for most of yesterday afternoon and it cooled nicely. Thanks everyone for the info.

[dougrainer]

holstein13 wrote:

dougrainer wrote:

holstein13 wrote:
I'm running three 15M A/Cs at a time. No problem. We even have electric water heat, washer, dryer, microwave, washing machine and battery chargers but not all at the same time. The power management system sheds power starting at 45 amps per leg.

What EMS do you have? ALL the EMS systems I have seen and worked on, when on 50 amp service, the SHED is disabled. Most EMS systems, when on 50 amp service, the amp draw goes blank, because 100 amps is more than enough service for the motorhome(sub 500k cost). Doug

I don't know what EMS system it is because it's built in to the Trip Tek system. It's very interesting because it has shed settings for both 30 amp and 50 amp. The other day, I hooked up an adapter to 30 amp because that was all that was available and the system auto-sensed the 30 amp and applied the shed settings for that.

I usually don't bump up against the limits at 50 amp except when I first arrive at a camp site. That's when the electric water heaters kick in at full blast and the battery chargers come on at full blast and all three A/Cs also want to go on. The system nearly always sheds at 50 amps when I first hookup.

Just talked to Newmar. Your system is thru the Silverleaf, not the Trip Tek. Your model King Aire has a LOT of hi draw 120 appliances and yes, on your particular RV, you can easily go over the 100 amp threshold, with the 3 roof AC units running.
3 AC units 45 amps
1 Oasis units 12 amps
2 Inverter/Chargers 20 amps

You are at 75 amps before running the Refer/Cooktop/dishwasher,etc. Do you have the all Electric model? That pulls a lot more AC amps than the standard model with some LP appliances. Plus you have 16 AGM batteries instead of 8. Doug

[holstein13]

dougrainer wrote:

holstein13 wrote:
I'm running three 15M A/Cs at a time. No problem. We even have electric water heat, washer, dryer, microwave, washing machine and battery chargers but not all at the same time. The power management system sheds power starting at 45 amps per leg.

What EMS do you have? ALL the EMS systems I have seen and worked on, when on 50 amp service, the SHED is disabled. Most EMS systems, when on 50 amp service, the amp draw goes blank, because 100 amps is more than enough service for the motorhome(sub 500k cost). Doug

I don't know what EMS system it is because it's built in to the Trip Tek system. It's very interesting because it has shed settings for both 30 amp and 50 amp. The other day, I hooked up an adapter to 30 amp because that was all that was available and the system auto-sensed the 30 amp and applied the shed settings for that.

I usually don't bump up against the limits at 50 amp except when I first arrive at a camp site. That's when the electric water heaters kick in at full blast and the battery chargers come on at full blast and all three A/Cs also want to go on. The system nearly always sheds at 50 amps when I first hookup.

[dougrainer]

holstein13 wrote:
I'm running three 15M A/Cs at a time. No problem. We even have electric water heat, washer, dryer, microwave, washing machine and battery chargers but not all at the same time. The power management system sheds power starting at 45 amps per leg.

What EMS do you have? ALL the EMS systems I have seen and worked on, when on 50 amp service, the SHED is disabled. Most EMS systems, when on 50 amp service, the amp draw goes blank, because 100 amps is more than enough service for the motorhome(sub 500k cost). Doug

[holstein13]

I'm running three 15M A/Cs at a time. No problem. We even have electric water heat, washer, dryer, microwave, washing machine and battery chargers but not all at the same time. The power management system sheds power starting at 45 amps per leg.

[Ivylog]

Yes I've been able to run all three of mine on 50A the few times I've needed them and that's the reason my rig has a 10K generator, not a 7.5.
Unfortunately when you need three ACs everyone else in the CG is using all they have too. Your management system is going to shut your rig down around 108 V to protect mainly any motors/compressors. The closer you are to the transformer supplying the power the better chance you have of higher Voltage. This drop is usually a CG problem of too small wires for the distance from the transformer and more likely a problem when they only have 30 amp service.

[dougrainer]

Kayteg1 wrote:
Would not hurt to measure AC draw.
My 15k Carrier draw 8.2 amp while running, so theoretically I could run 3 of them on 30 amp service, but the motors have huge spike while restarting and that is why they require bigger power line.
Common sense if you want to use 3 of them is to set thermostats on 2 to low and let the 3rd one cycle when it gets too cold.
That will avoid the potential situation when 2 might want to restart in the same time.

I do not know where you are getting your figures, but ALL RV Carrier units draw a minimum of 12.7 amps(Compressor and HI fan) at 95 degrees ambient. DROP 1 amp for each 10 degrees below 95. That means if you are pulling 8.2 amps, then the outside temp would be about 55 to 60 degrees????? IF that 8.2 is the compressor only, then you need to add the 2.5 to 3.0 amps for the fan motor. Which means you are pulling 10.7 amps at 75 degrees. Then why run the AC???? The ONLY exception to this is a Carrier 220 volt RV AC unit, which I have never seen and I doubt any OEM would have installed one. Doug

[Executive45]

Heat pumps or A/C..all three, never a problem...Dennis

[Golden_HVAC]

You can run all three on the 50 amp service. As explained above, there are 50 amps on each leg, or about 6 KW per leg, 12 KW total.

The start up amperage is around 30 amps for a couple of seconds, and the 50 amp breaker can handle a 200 amp load for 2 seconds without tripping.

Each unit should not be drawing more than around 12 amps, and if one is on one leg, the other two can be on the other leg, so max 25 amps on one side, 13 on the other. Your battery charger, refrigerator, and other appliances will work fine on the 50 amp service.

However if you are in a park with 30 amp max, then you will be restricted to only 2 of the A/C units if EVERYTHING else is off. If you have a residential refrigerator, then you could run one A/C and the refrigerator can cycle on and off, along with other loads. The residential refrigerator is probably about 3-5 amps load.

Good luck,

Fred.

[John_S_]

Run three all the time including right now on the generator.

[Roadpilot]

We run 4 AC units all the time. Popped the breaker once when the DW also had the stove, crock pot and electric floor steamer on at same time.

[Kayteg1]

Would not hurt to measure AC draw.
My 15k Carrier draw 8.2 amp while running, so theoretically I could run 3 of them on 30 amp service, but the motors have huge spike while restarting and that is why they require bigger power line.
Common sense if you want to use 3 of them is to set thermostats on 2 to low and let the 3rd one cycle when it gets too cold.
That will avoid the potential situation when 2 might want to restart in the same time.

[Blaster_Man]

rgatijnet1 wrote:
...50 amp service is actually 100 amps total...

Yes...two legs with 50 amps each. It will run three ACs easily.

[Two_Jayhawks]

Thanks everyone. We have been in a CG with no trees and 95+ temps and humidity for several days. Two units does well until about 3:00 or so and then the cabin looses a little ground. We'll go ahead and turn on the third unit today.

[Stealth1]

Your signature indicates you are operating a Newmar Dutch Star... Newmar coaches will run 3 ACs and oodles of other "stuff" without breaking a sweat!! You were told WRONG my friend!! Not to speak heresy, but I would suggest you also join the IRV2 Forums and link to the Newmar owners section! The information available there is unbelievable!!