Did you see the ad for the External “Soft Start”

[Morich]

I admit to rarely reading most ads but this is one that caught my eye and thought I might point it out as something to look over?

https://camperreport.com/cool-summer...ve-rv-upgrade/

I know we have often had mention of the soft start to install on AC units but that puts it out for many. Especially the folks who don't want to climb on the roof?
This appears to be a single unit plug-in type like a surge protector so maybe a good fit for a wider market as it leads one to believe one unitl serves all AC units on an RV?
Maybe something to look over. I stopped before reading the price, so your choice from here!!!

[Ray,IN]

A hard start cap does practically the same thing, just in a different form. It cost much less too, about 1/10. Keep in mind this website sells soft-start devices.
https://www.briskheat.com/news-event...-vs-hard-start
This is an impartial assessment of both capacitors:
https://www.ecmag.com/magazine/artic...kits-necessary
This explains the differences in a different way, with more detail.
https://www.coastalclimatecontrol.co...=default&page=
Each individual must assess their situation are act accordingly.

[creativepart]

Richard that product or one like it by another manufacturer has been available for a few years now. There have been a few others looking for reviews on how it works but there hasn’t been a lot of comments on this.

I purchased two soft starts for my motorhome but my wife has requested that I stay off the roof. So, I hired a mobile tech to come to the house to install them. That happens next Monday.

I figure that I could save some money and install them myself but I have to agree with my wife that I’m not all that steady on the ground.

[Morich]

I had not seen the combined unit and begin to get flak about some of the things I want to do, so thought something that could just be plugged in might be just right for some folks!
I'm sure the item is going to be more expensive but it might be a tossup if we are looking at hiring labor!
Falling off the roof can get even more expensive, so there is that point!

[creativepart]

There are all kind of question about how that device works with surge protectors and othe EMS devices. As to to cost would you believe $1200+ on sale for $795.

[thompwil]

A head scratcher for me. A true soft start uses thyristors (pulse width modulation) to ramp up the voltage and current for a specific time period minimizing the initial surge. A soft start attached directly to the AC reduces voltage drops and current dips that would otherwise be felt by all other devices in the coach during start up.

This device is a current limiting device that will limit current to every device in the coach at the time of a startup surge. The principles of Ohms Law, and Kirchoff’s law still apply. Limiting current supplied to the entire coach will limit current to every branch circuit proportionally during an AC start up. I’m struggling to see the value in it.

[Americanrascal]

Waiting for one to be delivered. Paid for it- but on long back order which has me concerned. If it works it will be a big help for us when we go to 30 amp only service locations. Hoping it meets needs of our 50 amp rig

[powercat_ras]

A hard start will not reduce the 1/6 second 60 amp in-rush current when a electric motor with start and run windings goes from stationary to rotating. It may increase it as the function of a hard start is to give a older tired motor higher starting torque. The only way to get more torque is to have more current or higher voltage.

A soft start limits the in-rush current to about 24 amps but the 24 amps flows for a longer time (1/3 second). A soft start may cause problems if the AC compressor motor is not in good shape and is taking higher than original amount of torque to start up.

It is technically feasible to have the soft start current limiting in the RV power cord and not right on the AC unit. Mike Sokol has tested both kinds and both work as claimed.

[thompwil]

Having installed hundreds of industrial soft starts and taught seminars on them. I can tell you without a doubt this device is not technically a soft start. By virtue of function it is a line current limiter.

The purpose of a soft start is to protect high inertia equipment from start-up damage, and to reduce power consumption & surges on start-up. A true soft start also protects circuits on the same feeder from momentary voltage dips and current deprivation through a controlled startup of the device itself.

This device will actually produce current deprivation onto every coach branch circuit by limiting all available feed current. Based on Ohms law, it may actually amplify the undesirable effects since the branch circuit demanding the most current (the AC startup) will momentarily steal from all other branch circuits what is made available via the line current limiting device.

OK so it may work with a generator or power pack, but at what long term cost? It is essentially inducing a brown out onto the entire coach for every AC startup. A hard wired AC soft start will actually eliminate the root cause of startup problems while protecting the AC unit itself and all other 120vac devices in the coach. I'll pass on this one.

[Ray,IN]

Thompwil, thank you for your professional assessment of this device.

[Morich]

I have no dog in this fight and only mentioned it as something for the folks who have two AC and want to avoid the roof.
I don't like solid state things that are hard to find info on what and how they do things, so no opinion from me on good or bad as I have not found need for either type and that leads to a high level of "dis-interested"!

[powercat_ras]

https://www.rvtravel.com/rv-electric...dl-the-turtle/

This article has some pretty curves of what an AC draws when starting up and what it drops to while running, and how those curves are captured, for those geeks like me out there.

I have the Soft Start RV mounted in the AC housing right at the compessor and this is what it does. It makes a huge difference in the max current the AC draws when starting up. It lets me run my AC off a 3,000 watt inverter tied to my 400 AH Lithium Iron Phospate Battery Bank and 1500 Watt Solar Panel Array for a few hours. Enough to knock the heat and humidity out of the RV before bedtime.