Running two A/C's on 30Amps?

[Chance]

Originally Posted by JamieGeek

Well this has been a bit of a surprise LOL: Not a single comment about the Easy Start unit reducing the surge current at startup (and the noise).

Seems to me that is the biggest reason its difficult to run two A/Cs off 30 amps. I've been able to run the A/C in all our RV's off the 15 amp circuit (not all at once ) in the garage if I'm careful about what else is running on that circuit when the compressor kicks on. The Easy Start guy may fix that (and also kill the startup noise which my wife hates).

I should have been more direct with post #2. Sorry. However, your title was about running 2 A/Cs on 30 Amps, not about soft starters. Again, I apologize.

Soft start allows starting two larger A/Cs, but why would you want to on a rig small enough that it came from factory with a single 15,000? You might be able to get them started, but then there is so little power left you can’t do anything else.

If you settle for about 50% cooling capacity increase, then I’m not sure you need the soft start anyway, so why spend the money? Granted I had not considered the start-up noise which I often avoid by setting thermostat very cold so A/C doesn’t turn off.

Anyway, since no one had responded to thread, I shared news on additional Power Saver models because they may play a role in powering 2 A/Cs from 30A service.

[Pete'sMH]

One of he best arguments for 2 units is to have at least some cooling if there is a problem with the AC. I had my single unit fail on a summer day many years ago in an 18 ft. travel trailer. It was only like 80 degrees but became so miserable inside that we had to abort the trip.

[The Gritz Carlton]

^^^BINGO^^^...anyone that knows me knows I'm all about "back up" everything. "One in None...Two is One".

[Bob Denman]

Spoken like a NASA engineer!

[Chance]

I watched video a second time, and noticed he has two 15,000 BTU/hr Penguins, which for newer A/Cs are rated at 1762 Watts at 115V. In video he mentions and shows they pull lower current after startup, but I’d bet that if left running for a while on a hot day, the 1762 Watts isn’t too far off, which is 15 Amps or higher.

So, to my previous point, running two of these on 30A service isn’t something I’d count on doing. Not enough margin. I can see that if he started out with one 15000 Penguin, that adding a second identical unit to match would be tempting.

However, if you have to add two soft starters at ~ $300 each, why not replace both A/Cs instead?

Originally Posted by JamieGeek

Well this has been a bit of a surprise LOL: Not a single comment about the Easy Start unit reducing the surge current at startup (and the noise).

Seems to me that is the biggest reason its difficult to run two A/Cs off 30 amps. I've been able to run the A/C in all our RV's off the 15 amp circuit (not all at once ) in the garage if I'm careful about what else is running on that circuit when the compressor kicks on. The Easy Start guy may fix that (and also kill the startup noise which my wife hates).

[Bob Denman]

I wonder if that Easy-Start unit will help to prolong the life of the /c?

[The Gritz Carlton]

His "disclaimer" at 3:01..."but you can use any power source that you've successfully run your air conditioners on before". If they've run successfully on that power source before...why do you need to change it??

[Bob Denman]

Less amperage draw at startup?

If you're just running on a/c: no problem!
It's when you want to fire up the second one on the same circuit...

[The Gritz Carlton]

He said..."air conditioners"

[Long & Winding road]

Originally Posted by The Gritz Carlton

His "disclaimer" at 3:01..."but you can use any power source that you've successfully run your air conditioners on before". If they've run successfully on that power source before...why do you need to change it??

Good point but sometimes you get the extra sensative breakers that trip when you look at them crosseyed.

Or if you shore powers works find but you want to use your $5K lithium power bank that you told your wife would run the AC's fine for a few hours and you "just have to have them".

[JamieGeek]

Well I went and did it anyway, installed the EasyStart on our Axis.

Didn't take any pictures because they did already. The installation manual (pdf) pictures (pages 4-9) exactly matched our Coleman Mach.

After installation our A/C doesn't draw any more than 12 amps (the initial 5 amps is just the fan on the A/C running):

https://www.youtube.com/watch?v=ETEqj_yF2Xw

Now I'm not going to install a 2nd A/C. I installed it for two reasons:

• With it only drawing 12 amps max I can run it off a 15 amp circuit
• On startup there is no more loud clunk (can't even hear anything in the above video)

Are those reasons enough for $300? I guess they were for me (a good nights sleep is invaluable LOL--I know the wife is going to love it--that alone is worth a lot LOL).

I did notice a drawback: The EasyStart doubles the compressor off time (I think its 10 minutes after running vs 5 minutes normally). Thus if you're somewhere hot enough that the A/C cycles a lot I can see it being a little warmer in the coach with the compressor not running as much.

[16ACE27]

Not sure why it would change the restart delay. But the good news is now you can run the AC off a Honda 2000 inverter generator. They could always start the ACs, they just tripped out on overcurrent after a few minutes. They're rated at 13.3 amps continuous.

[JamieGeek]

Originally Posted by 16ACE27

Not sure why it would change the restart delay. But the good news is now you can run the AC off a Honda 2000 inverter generator. They could always start the ACs, they just tripped out on overcurrent after a few minutes. They're rated at 13.3 amps continuous.

The restart delay change is designed into the unit.

[Chance]

Originally Posted by 16ACE27

Not sure why it would change the restart delay. But the good news is now you can run the AC off a Honda 2000 inverter generator. They could always start the ACs, they just tripped out on overcurrent after a few minutes. They're rated at 13.3 amps continuous.

Heat most likely. It needs time to cool off — either the device itself and or the compressor must be getting warm during start-up.

Once A/C is running, current should be the same, so I’m not following your Honda example. It’s usually the other way — small generators can’t start A/C but could keep it running if already started, which is where these soft starts help most.

[Beau388]

30 amp circuit breakers are rated at 28 amps continuous when new. Every time they are tripped they degrade a little. The 30 amp circuit breaker can handle 30 amps for about 10 minutes before it trips. My coach was refitted with an EMS. The main 15,000 Coleman Mach 15 draws 15 amps when turned on (after compressor spin-up). On hot days after running for an hour or more its draw is up to 18 amps total. My Coleman Mach 8 Cub draws 12 amps and temperature doesn't seem to matter. So no, both will not operate for very long on 30 amps on a hot day. I haven't tried it on a 80 degree day as only one A/C is need to keep the coach cool.

[16ACE27]

Originally Posted by JamieGeek

The restart delay change is designed into the unit.

Sure, but my question was "why". BTW, what size is your AC?

[16ACE27]

Originally Posted by Chance

Once A/C is running, current should be the same,

I would agree but Jamies said he is only pulling a max of 12 amps now - don't know what it pulled before the mod.

Originally Posted by Chance

I’m not following your Honda example. It’s usually the other way — small generators can’t start A/C but could keep it running if already started, which is where these soft starts help most.

You would think so but i have seen the Honda 2000s start 15K BTU ACs but trip out after about a minute. I don't think the competitors can start them but that Honda handles the starting current like a champ.

[The Gritz Carlton]

My Honda 2000 will not run one A/C. At startup, the fan comes on first for a few seconds...no issues...the second the compressor tries to kick in, the breaker on the 2000 pops. It doesn't take a few minutes. the Champion 3100 will run one of them but it seems like a labor of love for a second or two as the compressor kicks in.

[JamieGeek]

We have the smaller 13.5k unit on our Axis which ran 12 amps before the mod--the mod doesn't change the running current draw, just reduces the start current (the video at the beginning of this thread shows that).

In another thread where I installed that volt/amp meter I measured a bunch of things and pretty much all the high current appliances in our coach (hair dryer, water heater on electric, air conditioning, hot plate, microwave, etc.) draw about 12 amps (which makes sense since a few were designed to operate off of a 15 amp circuit).

I don't have a picture of the volt/amp meter showing the starting current of our A/C prior to the mod, however. I believe that was somewhere around 20 amps if I recall correctly. I do know that it would blow the house breaker on our 15 amp garage circuit when the compressor would kick in.

[Chance]

Originally Posted by JamieGeek

......cut.....

I don't have a picture of the volt/amp meter showing the starting current of our A/C prior to the mod, however. I believe that was somewhere around 20 amps if I recall correctly. I do know that it would blow the house breaker on our 15 amp garage circuit when the compressor would kick in.

I doubt normal volt/amp meters can capture the initial and almost instantaneous current that A/C compressors draw when they first get power. Manufacturers like Coleman list the Lock Rotor Amps (LRA) in spec sheets, and it’s always much higher than 20-Amp range. The lowest I’ve seen is in the low 40s for the 11,000 BTU/hr Power Saver, with most being in the 50s and 60s. But this happens for only a very small fraction of a second as you know.

I’ve measured the start-up current on my A/C with a hand held Amp clamp that records the peak, and it doesn’t come close to the LRA either.

Regarding Honda 2,000/1,600 Watt generators, there are plenty of reports of them starting 11,000 Power Saver A/Cs. I suppose the newer 2,200/1,800 Watt generators should do even better. It would not surprise me if they could start a 13,500 Power Saver.



P.S. — To your point about time delay due to soft start being an issue in hot weather, I doubt it will be noticed, but if it is under those conditions, a simple fix is to just set A/C temperature lower so it doesn’t cycle off for a minute or two. A couple of degrees cooler should keep it running 100% of the time under those conditions.