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I have recently (finally) set my house up for generator backup in the event we lose power again...I have a 7kw continuous (9kw start up) portable generator for this event. Pretty much everything we need can be supported by this as we have all gas appliances, and city water. The item in question is central AC (3.5 ton). I have come across a couple of different ways to reduce the initial electrical draw, one being soft start, and the other hard start. Both seem to accomplish the same goal...Thoughts on the better way to go?
Soft start: https://www.youtube.com/watch?v=uowVMYuPs-U
https://www.amazon.com/s?k=soft+start+fo...doa-p_4_10
Hard start: https://www.youtube.com/watch?v=ptYSLkP62LY
https://www.amazon.com/s?k=hard+start+ki...doa-p_4_10
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06-27-2022, 04:20 PM
(This post was last modified: 06-27-2022, 04:22 PM by atgcpaul.)
I was just looking into this yesterday, too!
If you scroll down in the comments of the hard start video, the presenter says he has a soft start on his house and it's a combination of your AC size and how big your generator is.
The generator I think I will get has the same output as yours with a 50A output, but I think it's recommended you aim for less than that so I will be using the soft start.
Damien Johnson--I'm curious, I just watched your installation video on soft start kit and then one on you installing the hard start kit a month later. Which one did you end up sticking with for use?
How To Home--Hey Damien, on my AC I have the soft start kit installed still. I installed the hard start kit on another home as it was a much smaller AC unit with a very large generator so it just needed a little boost to help with everything. Both the hard start and soft start have their place, just depends on the situation.
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(06-27-2022, 04:20 PM)atgcpaul Wrote: I was just looking into this yesterday, too!
If you scroll down in the comments of the hard start video, the presenter says he has a soft start on his house and it's a combination of your AC size and how big your generator is.
The generator I think I will get has the same output as yours with a 50A output, but I think it's recommended you aim for less than that so I will be using the soft start.
Damien Johnson--I'm curious, I just watched your installation video on soft start kit and then one on you installing the hard start kit a month later. Which one did you end up sticking with for use?
How To Home--Hey Damien, on my AC I have the soft start kit installed still. I installed the hard start kit on another home as it was a much smaller AC unit with a very large generator so it just needed a little boost to help with everything. Both the hard start and soft start have their place, just depends on the situation.
Reading thru the comments, I really did not see a solid answer regarding which is better, and maybe there is no such correct response. With the hard start being ~1/10th the cost of a soft start, I suspect there must be a reason.
I am sure you know this, but...the generator I am using is good for about 30amps output at 240volts. Not to say you couldn't wire your home for 50amp...My understanding is that typically a generator will shut down if overloaded...
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This doesn't really answer brianwelch's question, but is a minor variation on what he is doing that may help someone. My similar setup is with a much smaller portable generator that will run only the bare essentials; refregerator, a few lights, a small tv, a small fan, and a 5000 btu window AC. The AC cools two rooms that can be closed off from the rest of the house and is enough to survive in the humid hot south. Also, the generator is converted to run on natural gas which eliminates the need to hunt down non-existing gasoline during a regional power outage. Also, this eliminates brian's concern about the central AC.
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Brian, you need to do to things. One, estimate the base load on the generator (you can turn off everything you do not intend to run off generator and take an amp reading off one leg of 240 v. two, start the AC unit with the basics running and see what your current draw is. A 9 kw should put up 37 amps at 240 v. Depending on how fast teh system can come up to speed will determine if the generator will work in this application.
During Hurricane Laura and Delta I was unable to use anything beyond refrig, coffee pot, lights, ceiling fans and 2, 5000btu window units from a 7kW generator.
My good friend ran his house off of a small stationary unit by load shedding to allow starting of the AC unit. He never allowed the AC unit to turn off thus only needing to provide current for running amps and not start up surge.
If you have access to natural gas I strongly recommend that you take advantage of it. Having gone thru 7 hurricanes, looking for fuel is not fun.
Hope this helps.
Greg
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07-04-2022, 07:17 PM
(This post was last modified: 07-05-2022, 10:20 AM by brianwelch.)
Thanks Greg...We do have NG, just not sure whether the the capacity is there to support the added load of a generator. I suspect a call to the utility company could resolve that. I am also not looking forward to drilling thru the foundation stone again (unless I am permitted to add some fittings and a valve on the exterior piping, post meter of course)
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(07-04-2022, 07:17 PM)brianwelch Wrote: Thanks Greg...We do have NG, just not sure whether the the capacity is there to support the added load of a generator. I suspect a call to the utility company coud resolve that. I am also not looking forward to drilling thru the foundation stone again (unless I am permitted to add some fittings and a valve on the exterior piping, post meter of course) My NG piping already had an external valve on it where I could connect my generator. Check with your gas company and/or plumber. I talked with my gas company before I did it and they were more than happy to have it done as they would sell more gas. This works great on my portable (can't remember; 3500 or 5500 watt). I purchased a conversion kit for it that was way over priced, but it does work. Of course, you can buy portables these days that are already set up to burn gasoline or NG.
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NG is the way to go if you can. I needed a larger capacity meter when I had a 17 KW whole house generator installed several years ago. It had to be able to handle the highest load scenario and the one I had could not. I think it cost a couple hundred $'s.
I'm sure you've weighed your options, but I'll just point out that the worst time to have a power failure is when you are far away from home and can do nothing about it. Sump pump, furnace, refrigerator, freezer, everything critical no longer works. I no longer worry about that much. The power goes out, the transfer switch kicks in, and power is restored in about 15 seconds.
John
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