Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 25-09-2018, 18:02   #1
Registered User

Join Date: Jan 2017
Location: Everywhere
Boat: 2011 FP Orana 44 M
Posts: 732
Soft start options for Air Conditioning

Have you installed a soft start unit on your air conditioner(s)? What product did you use? What were your results?

The Dometic branded one seems to cost nearly $600.

https://citimarinestore.com/en/domet...290339977.html

The Micro-Air is half that at $300.

https://www.microair.net/collections...nt=30176048267

Are there any negatives to this type of thing, or alternatives that are superior in some way? I'd like to install one on the master cabin A/C unit, but they're so expensive I don't think I'd be getting one for the the other units on board.

The generator has trouble kicking on the A/C while it's also charging the batteries, and I'd like to consider having A/C options in the future on battery for a couple hours to cool/dehumidify the cabin before bedtime. I have an M2812 inverter and 900Ah of battery, so that aspect is at least mostly ready for it.
__________________

LoudMusic is offline   Reply With Quote
Old 25-09-2018, 19:17   #2
Registered User

Join Date: Oct 2015
Posts: 1,397
Re: Soft start options for Air Conditioning

Quote:
Originally Posted by LoudMusic View Post
Have you installed a soft start unit on your air conditioner(s)? What product did you use? What were your results?

The Dometic branded one seems to cost nearly $600.

https://citimarinestore.com/en/domet...290339977.html

The Micro-Air is half that at $300.

https://www.microair.net/collections...nt=30176048267


Are there any negatives to this type of thing, or alternatives that are superior in some way? I'd like to install one on the master cabin A/C unit, but they're so expensive I don't think I'd be getting one for the the other units on board.

The generator has trouble kicking on the A/C while it's also charging the batteries, and I'd like to consider having A/C options in the future on battery for a couple hours to cool/dehumidify the cabin before bedtime. I have an M2812 inverter and 900Ah of battery, so that aspect is at least mostly ready for it.
It's a tough spot when the generator is too small for a load that lasts 2 seconds, but fine the rest of the time.

There are a few options, some of which might have other benefits.

There are inverter/chargers that can pull power out of the batteries when the load exceeds a preset value. That happens on startup of our AC units, the inverter bumps the power for a few seconds drawing from the battery. It's a trivial drawdown from the batteries, but makes a huge difference in the peak load on the genset. Its more expensive than the soft start, but it might upgrade your whole electric system too.

The advantage of an integrated inverter/charger is that the good ones can automatically cut back on the battery charge amperage when other loads need the power.

The soft start system should not be needed if you are running the AC from a good inverter. Most inverters have peak loading far higher than "steady state."

In fact, that might be an answer for you... Wire the AC units directly to the inverter, so that's their ONLY source of power. They will start without unduly loading the genset, and the battery charger will keep things running smoothly. It seems at first to be a roundabout way of doing things, but "inverter only" boats are not uncommon, and are a way of supplying AC to the boat without the complications of connecting to the shore power safety ground. Nigel Calder talks a lot about the advantages of this in the latest edition of his book.

I know of no downsides to the "soft start" technology--other than the damage they do to your wallet. To me they seem to be needed only to patch problems from the design of the rest of the electrical system.
__________________

billknny is offline   Reply With Quote
Old 25-09-2018, 22:40   #3
Registered User

Join Date: Jan 2017
Location: Everywhere
Boat: 2011 FP Orana 44 M
Posts: 732
Re: Soft start options for Air Conditioning

Quote:
Originally Posted by billknny View Post
It's a tough spot when the generator is too small for a load that lasts 2 seconds, but fine the rest of the time.

There are a few options, some of which might have other benefits.

There are inverter/chargers that can pull power out of the batteries when the load exceeds a preset value. That happens on startup of our AC units, the inverter bumps the power for a few seconds drawing from the battery. It's a trivial drawdown from the batteries, but makes a huge difference in the peak load on the genset. Its more expensive than the soft start, but it might upgrade your whole electric system too.

The advantage of an integrated inverter/charger is that the good ones can automatically cut back on the battery charge amperage when other loads need the power.

The soft start system should not be needed if you are running the AC from a good inverter. Most inverters have peak loading far higher than "steady state."

In fact, that might be an answer for you... Wire the AC units directly to the inverter, so that's their ONLY source of power. They will start without unduly loading the genset, and the battery charger will keep things running smoothly. It seems at first to be a roundabout way of doing things, but "inverter only" boats are not uncommon, and are a way of supplying AC to the boat without the complications of connecting to the shore power safety ground. Nigel Calder talks a lot about the advantages of this in the latest edition of his book.

I know of no downsides to the "soft start" technology--other than the damage they do to your wallet. To me they seem to be needed only to patch problems from the design of the rest of the electrical system.
Wow this is a quality reply - thank you!

What's your opinion on "wear and tear" of the inverter by having the A/C run through it? Seems like logically it would just be passing current from the genset or shore power until those are not present, at which time it goes to battery, which obviously starts generating a not insignificant amount of heat.

The specs on my MS2812 are:

Inverter Specifications
1 msec surge current (amps AC): 70
100 msec surge current (amps AC): 40
5 sec surge power (real watts): 3900
30 sec surge power (real watts): 3800
5 min surge power (real watts): 3200
30 min surge power (real watts): 3000
Continuous power output at 25į C: 2800 VA
Rated input battery current: 267 ADC
Continuous output at 25į C: 125 ADC

Nearly as I can tell, it takes more than 100 msec to spin up an A/C unit, so the 5 second time becomes critical. That's 32.5A@120vAC, which is about 3.5x operational draw. I've read that startup can be as much as 10x, but maybe the shorter surge values would cover that portion of the spikes.

I think the problem then becomes having enough "input battery current" to start the A/C without shore or genset power.

More to think about ...
LoudMusic is offline   Reply With Quote
Old 25-09-2018, 22:57   #4
Registered User

Join Date: Apr 2017
Location: Southern California
Boat: Looking
Posts: 24
Re: Soft start options for Air Conditioning

I have used the easy start with success. Installed myself on Dometic unit. Great co.
Brav is offline   Reply With Quote
Old 26-09-2018, 03:39   #5
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 5,287
Re: Soft start options for Air Conditioning

If you want to use an inverter consider getting one that has a "generator assist" feature. With these the inverter only kicks into action during the startup and then drops out allowing the generator to run the AC.

It's unlikely that any inverter charger can keep the batteries charged whilst also running the entire AC load. What size AC do you have?
transmitterdan is offline   Reply With Quote
Old 26-09-2018, 03:50   #6
Registered User
 
Sulaire's Avatar

Join Date: Oct 2011
Location: Planet earth
Boat: Hans Christian 41
Posts: 236
Re: Soft start options for Air Conditioning

+1 for easy start, very good, you can hear how the air con comes on in stages, making the turn on smooth over around 10 seconds rather than all at once, hence no big spike of current. I would think it makes the start up less wear and tear in the long run. No problems on a honda 2.0 gen, 16,500 btu mermaid aircon. Our victron 3000/120/12 multi plus handles it too without honda.
Sulaire is offline   Reply With Quote
Old 26-09-2018, 08:44   #7
Registered User

Join Date: Jul 2018
Location: Kemah TX
Boat: Cruisers Yacht, 3870 - 43 LOA
Posts: 173
Re: Soft start options for Air Conditioning

Take a look at this video from Gone with the Wynns. They do a 12 minute video on the benefits of Soft Start for the the AC on both their generator and inverter. Should answer your questions. They even do a test showing the spike in amps without the Soft Start and what it looks and sounds like when Soft Start is in use.


https://youtu.be/yjK1Gi_u6ss
ShellBack89 is offline   Reply With Quote
Old 26-09-2018, 08:54   #8
Registered User

Join Date: Oct 2014
Location: Panama City Beach, FL
Boat: Beneteau 343
Posts: 254
Re: Soft start options for Air Conditioning

Quote:
Originally Posted by Brav View Post
I have used the easy start with success. Installed myself on Dometic unit. Great co.
Is it just a matter of connecting a few wires? No configuration or other fuss needed? I have a 16,000 BTU unit and like the idea of using a H2000 generator.
EmeraldCoastSailor is online now   Reply With Quote
Old 26-09-2018, 09:00   #9
Registered User

Join Date: Jan 2017
Posts: 10,970
Re: Soft start options for Air Conditioning

Ideal is when that functionality is part of the system design.

Frigomar looks great from that POV
john61ct is online now   Reply With Quote
Old 26-09-2018, 09:05   #10
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 5,287
Re: Soft start options for Air Conditioning

Quote:
Originally Posted by EmeraldCoastSailor View Post
Is it just a matter of connecting a few wires? No configuration or other fuss needed? I have a 16,000 BTU unit and like the idea of using a H2000 generator.


Itís unlikely you can run a 16K unit on a H2000 generator. It might work for a few hours but probably not day in and day out.
transmitterdan is offline   Reply With Quote
Old 26-09-2018, 09:15   #11
Registered User

Join Date: Jul 2012
Posts: 200
Re: Soft start options for Air Conditioning

I talked to several AC guys here and they recommended an AC Supplu kit that is about thirty bucks. Basically a capacitor that wires into the system they put them on all the time. Doesn't have the fancy package but exactly what is built into most modern home and industrial AC units...just smaller.
__________________
Brent
Snowgoose
The two most important days, are the day you were born, and the day you figured out why. Mark Twain
rbrentp is offline   Reply With Quote
Old 26-09-2018, 09:33   #12
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 24,776
Soft start options for Air Conditioning

Quote:
Originally Posted by transmitterdan View Post
Itís unlikely you can run a 16K unit on a H2000 generator. It might work for a few hours but probably not day in and day out.


People do it all the time.
It works the little Honda hard cause itís max continuous draw is 13.3 Amps, and a 16K AC usually pulls about 12 once running, but it can do it.
The newer 2200 Honda can Iím sure do it with less trouble than a 2000.

Replacing his Magnum MS2812 with a boost inverter, would be nuts. It would work, but at a much more expensive cost. Plus the Magnum if teamed with its remote control has many features other inverter / chargers may not.
a64pilot is offline   Reply With Quote
Old 26-09-2018, 09:48   #13
Registered User

Join Date: May 2015
Location: Baltimore, Maryland USA
Boat: Herreshoff Cat Ketch 38
Posts: 12
Re: Soft start options for Air Conditioning

[QUOTE=LoudMusic;2728907]Have you installed a soft start unit on your air conditioner(s)? What product did you use? What were your results?

The Dometic branded one seems to cost nearly $600.

Micro Air Easy Start, hands down.
I installed in an LG 14,000 portable unit. Yes, a portable unit. Removed a couple of dozen screws, pried apart the clamshell housing and gained access the the internals. From there, just followed the directions. I ran the wire bundle out of the unit with the factory power supply. The box sits on the floor next to the arco unit. My iGen 2500 starts it without breaking a sweat in efficiency mode. I paid $249.00 for the Micr Air unit from outfit in Millersville, MD. (just outside of Annapolis).

Coastal Climate Control
GuerrillaCamper is offline   Reply With Quote
Old 26-09-2018, 10:07   #14
Registered User

Join Date: Oct 2014
Location: Panama City Beach, FL
Boat: Beneteau 343
Posts: 254
Re: Soft start options for Air Conditioning

Quote:
Originally Posted by transmitterdan View Post
Itís unlikely you can run a 16K unit on a H2000 generator. It might work for a few hours but probably not day in and day out.
Now that I think about it, I don't think my unit is 16K BTU; more like 12 or 13K BTU. I assume that might make it easier for a H2000 to run it.
EmeraldCoastSailor is online now   Reply With Quote
Old 26-09-2018, 10:11   #15
Registered User

Join Date: Jan 2017
Posts: 10,970
Re: Soft start options for Air Conditioning

Absolutely no problem if the unit is efficient enough. Not in eco mode of course.

Frigomar's variable speed brushless inverter tech is apparently amazing, their 16000btu unit uses under 1400W.

And crazy slow controlled ramp up, no surge demand at all.
__________________

john61ct is online now   Reply With Quote
Reply

Tags
air conditioning

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Marine Air Reverse Cycle Heat and Air Conditioning Unit wolfesmy General Classifieds (no boats) 8 24-11-2016 17:12
How soft is "soft" mud when anchoring? troppo Seamanship & Boat Handling 39 10-08-2016 04:24



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 21:03.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.