AC Soft Start

[akadeadeye]

We're going to be in areas of the country early summer where there are mostly state parks with 30 amp service.  We need 50 amp to run both ACs.  What are your thoughts/experiences with these Soft/Easy Start devices.  Are they worth it?  Do they work as advertised?  Which brand do you recommend or which brand to stay away from?  Thanks.

Don

[bm02tj]

Hard start capacitors are for low voltage and help start not run 

only run one unit at a time as they do not help running amperage 

[manholt]

That begs the question, why pay for Soft/easy start?

Don, we got a 30A Autoformer, we found that most 30 amp connections in US and Canada is iffy at best.   

[jleamont]

Don, I’ve run both on 30 amp many times. As long as that’s the only thing on. Water heater on propane or Diesel only (depending on what you have) and refrigerator on propane (if residential, not an issue, doesn’t draw enough).

[kaypsmith]

Best solution to the problem that I have seen, is to use a 2000 watt guiet inverter generator to run the second unit in the heat of the day if that second one must be run at same time as other appliances.

[akadeadeye]

2 hours ago, bm02tj said:

Hard start capacitors are for low voltage and help start not run 

only run one unit at a time as they do not help running amperage 

bm02tj,

Thanks for the reply.  My understanding is the problem with 2-15,000btu ac units and 30 amp plug-in is that while one unit can kick on and run, using about 12 amps, if the other unit is needed and then kicks on, the start-up amperage kicks the total to above 30 amps and throws a breaker.  Whereas, with a soft start unit, the start-up amperage is diminished to a point the second unit can start up without the initial spike in amps and then both can run in the 25 amp range.  Is this correct?

Don

[manholt]

Don,

If it is, it still only leaves you 2 amp as a margin.  Remember, we can only use 90% of the 30 or 50 amp CB.  That's why, when your on 50 amp, it shows L1 at 45 and L2 at 45.  On a 30 it will show 27 amp!  

Carl

[kaypsmith]

2 hours ago, manholt said:

Remember, we can only use 90% of the 30 or 50 amp CB.  That's why, when your on 50 amp, it shows L1 at 45 and L2 at 45.  On a 30 it will show 27 amp!  

Duh!!!!!!! If the AC is rated maximum draw 12 amps, and you are using a true 50 amp service and no other devices are on at the time, then L1 will show 12 amps, and L2 will also read 12 amps because both units are 120 volts each and L1 is 120 volts on a seperate half a 240 volt circuit. If both units are turned on simultaneously on a 30 amp service and no other loads, then you will read 24 amps on that circuit. Each AC is supposed to be wired on seperate breakers on a 30 amp service. That is why it has been stated that both units can be run on a 30 amp service if no other high draw devices are being run at the same time. That true 50 amp service is actually 100 amps @ 120 volts, or 50 @ 240 volts.

[akadeadeye]

So, what I hear most of you saying is that the Soft Start devices are a waste of time and money?

[wildebill308]

12 minutes ago, akadeadeye said:

So, what I hear most of you saying is that the Soft Start devices are a waste of time and money?

Well My take is Yes ,No , Maybe. I have had RVs that the AC started  all at once. The newer AC units start the fan and then after it has stabilized it starts the compressor. This helps lower the big load of starting everything at once. Just curious, have you tried to run both on good 30 amp power? It would be interesting to see what the "actual draw was. I would definitely have a good Surge Guard to protect agents low voltage weather hooked up to 30 or 50 amp power.

Bill

[bm02tj]

It looks like a solid state hard start unit to lower inrush current 

Test run amps on units less than 24 amp go for it 

For the price difference I would try a hard start unit as it is a lot cheaper 

I just might try it next weekend as I have one in my work van 

[kaypsmith]

10 hours ago, akadeadeye said:

So, what I hear most of you saying is that the Soft Start devices are a waste of time and money?

There are current control devices in a lot of the newer coaches which I call current shedders, these devices actually will turn power off to other devices in order to stay within current limits to make sure that you never overdraw and cause a breaker to blow. The AC units that are currently installed on RV's use much more power to start up than to run continously. I have a mini-split unit in my coach which uses inverter technology, these units never stop running unless power is removed, this is the newest wave of refrigeration and I believe will become available to nearly all AC units in the future. Since it takes more power to start an AC than to run for an hour, the inverter tech just changes cycles (60) to more cycles to run faster, therefore it is sipping power at slow speed but not cooling very much, as the cycles are increased the cooling is increased and using a very minimal amount of current while cooling greater. Soft start technology is used in industrial applications with very large motors that run all day and require a huge amount of electricity to start. They are beneficial for industry to use because it keeps the power meter from seeing large spikes at a given time, and which the industry is actually penalized for allowing to happen. They have their place, but I don't believe would be cost effective for your situation.

[txiceman]

1 hour ago, kaypsmith said:

There are current control devices in a lot of the newer coaches which I call current shedders, these devices actually will turn power off to other devices in order to stay within current limits to make sure that you never overdraw and cause a breaker to blow. 

This is not just newer RVs.  We had a 1995 Avion 5th wheel (30 amp) that had a load management system to shed loads.  Worked great.

Ken

[akadeadeye]

12 hours ago, wildebill308 said:

Well My take is Yes ,No , Maybe. I have had RVs that the AC started  all at once. The newer AC units start the fan and then after it has stabilized it starts the compressor. This helps lower the big load of starting everything at once. Just curious, have you tried to run both on good 30 amp power? It would be interesting to see what the "actual draw was. I would definitely have a good Surge Guard to protect agents low voltage weather hooked up to 30 or 50 amp power.

Bill

We tried to run both once in a state park on 30 amp but we were at the end of a loop and voltage was about 112 or less, so it didn't work out.  Breakers would throw and generator would start, etc.  We do have a built in surge protector and EMS.

[wildebill308]

9 minutes ago, akadeadeye said:

We tried to run both once in a state park on 30 amp but we were at the end of a loop and voltage was about 112 or less, so it didn't work out.  Breakers would throw and generator would start, etc.  We do have a built in surge protector and EMS.

But that was more about low voltage than being 30 amps. A soft start will do nothing to offset low voltage.

Bill

[rayin]

First we need to understand exactly what happens with a Soft Starter: https://www.raymondinnovations.com/blogs/news/induction-motors-and-soft-starters

A Hard Start Kit defined:; https://georgebrazilhvac.com/blog/what-is-an-air-conditioner-hard-start-kit

Now we know why a Soft Start kit is generally inadvisable, and why a Hard Start Kit is beneficial in some instances. Neither will help alleviate your particular situation IMHO.

Edited April 22, 2021 by rayin

[charlesmoore03]

OK, at this late date, my 2¢:  I had a Honda 2000 generator and it ran my 11,000 BTU AC just fine.  Enroute to a summer Texas environment the AC quit.  I pulled into National RV in Shipshewana and he said it was too dead to fix and he did not have any 11,000 BTU replacement BUT he had a 13,500 BTU and we had it installed and were on the road within 2 hours.  When we got to Texas everything was fine and it was cool in the 100+ heat.  Later back at the Indiana homestead we tried the Honda 2000EU - pop goes the instantaneous electronic  breaker and again and again.  I called  National RV Refrigeration and told him the issue and he said it was an easy fix to install a soft start.  After that the Honda 2000EU could start the A/C.

So, yes it does work and it may or may not be related to line voltage but is definitely related to inrush current that occurs when the compressor comes up to its first compression cycle.  So I would say install the soft start kit and it is worth it for a 30A circuit with two A/C's which take about 23 - 24A steady state run current.

BTW - I have these installed on the Journey 36DL with basement A/C and it runs on 30A just fine but you do not get to use the microwave or the electric hotwater until the inside temperature is stabilized and only stage 1 of the A/C comes on.  If the temp outside is such that stage two comes on normally then no microwave or electric hotwater (gas only).  It will run a float charge on the battery and a Crockpot ( outside the coach).  End of the 2¢.  🙂

[raypesek]

I installed Micro-Air EasyStarts on my two Atwood AC-1511 15K BTU units and recently got the chance to test it. I was confident the EasyStarts would allow both A/C's to run because I have a friend with the same motorhome and the same A/C's and he full-times. He installed two EasyStarts and he can now run both A/C's on a 30-amp pedestal and does so regularly. So can I now. We have dogs so we really need to assure we can run both A/C's when necessary.

If we want to use the microwave we turn the front A/C off because both are on L1. If we want to use the Splendide washer/dryer we turn the bedroom A/C off because both are wired to L2. The fridge and water heater are switched over to propane. 

FWIW,

Ray

[bm02tj]

If you are on a 30 amp that is 125 not 220 so L1and L2  tied together 

[raypesek]

6 minutes ago, bm02tj said:

If you are on a 30 amp that is 125 not 220 so L1and L2  tied together 

Duh. Well, I guess I over-thought that a bit, eh? 🙄

I couldn't find it before but I just did. The article on soft starts linked to by rayin said damage could result with a soft start due to the start capacitor. At least with the Micro-Air EasyStart the start cap gets removed: http://www.micro-air.com/kb-easystart/articles_installation/easystart_Do_I_Need_To_Remove_The_ PTC_When_Installing_An_EasyStart.cfm

Do I Need To Remove The PTC When Installing An EasyStart?

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Yes, The below factory installed starting components will need to be removed or at least disabled before installing the EasyStart.

• Start Cap
• PTCR
• Start Relay etc...

[manholt]

charlesmoore03.  Welcome to the Forum! 

Thank you for informative information..