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Old 04-09-2016, 11:19   #106
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Re: 12 Volt air conditioner may be availabe soon

Just read a post where a guy is planning to operate 4 ton (40,000BTU) of Air Conditioning all night long on his boat with 1,780 Watts of solar panels. I live off grid with 4,200 watts solar with a 1,780 lb battery 1,380 Ah @ 24V & 6,000 watt backup Gen and I wouldn't dream of running a 5,000 BTU A/C all night. I have no panel shading at all like him. A shadow of a wire on your panels can cut your power way down also. I got to see his results when he posts them.
Average 2,000 sq ft house uses 2 Ton A/C where I live.
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Old 04-09-2016, 11:46   #107
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Re: 12 Volt air conditioner may be availabe soon

Rorzech,
I agree he's setting his bar too high.
BTW The latest soft start marine air cons are quite efficient.
For example there are 16,000 btu units drawing <1,500 watts.
With a 20kw bank (15kw available) you can run two units all night assuming the compressors cycle at 60% run time which is pretty typical with a well insulated boat.



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Old 04-09-2016, 14:59   #108
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Re: 12 Volt air conditioner may be availabe soon

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Rorzech,
I agree he's setting his bar too high.
BTW The latest soft start marine air cons are quite efficient.
For example there are 16,000 btu units drawing <1,500 watts.
With a 20kw bank (15kw available) you can run two units all night assuming the compressors cycle at 60% run time which is pretty typical with a well insulated boat.



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Thanks for that info. Concerning soft start, I was told I was foolish to even suggest think8ng of using a soft start for a airconditioner by the "experts" on this forum. They lectured me about the high power drain on start didn't matter because it would still eat up the same energy over a period time. I love these so called experts.

Thanks.

Chaya
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Old 04-09-2016, 17:22   #109
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Re: 12 Volt air conditioner may be availabe soon

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Originally Posted by GoingWalkabout View Post
Thanks for that info. Concerning soft start, I was told I was foolish to even suggest think8ng of using a soft start for a airconditioner by the "experts" on this forum. They lectured me about the high power drain on start didn't matter because it would still eat up the same energy over a period time. I love these so called experts.

Thanks.

Chaya
I was one of those who corrected your misunderstanding about soft-start. And none of us told you that you were foolish.

You thought that a soft start reduced total energy use.
Your exact words were: " I think you'll find that by eliminating the big start up spike you will conserve a lot of energy. "

You were simply corrected on this misapprehension.

No one said that they were not a good idea or denied that they reduced the initial load on startup.

Soft starts are an excellent addition to such a system because they reduce the size of generator or inverter you need to run the system - but they will not reduce energy usage, which was your stated reason for having one.
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Old 04-09-2016, 17:40   #110
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Re: 12 Volt air conditioner may be availabe soon

My 16,000 BTU hard starting Webasto pulls 11 amps at 120 VAC, that is 1320 watts. Pretty darn efficient when compared to my 5,000 BTU Webasto that pulls 5 amps at 120 VAC or 600 watts, roughly 1/3 the cooling, but half the power consumption, same brand name, same type etc. this includes the seawater pump.
My old 16,000 BTU pulled about 16 amps or almost 2,000 watts.
Tough to find out actual current draw before you buy though.


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Old 04-09-2016, 17:47   #111
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12 Volt air conditioner may be availabe soon

It comes down to a few truths.
1. You simply cannot make or generate or store power as cheap as you can buy it from a utility, meaning shore power.
2. You simply cannot make or generate or store power as cheap with Solar or wind than you can by burning Diesel in a generator, not when we are talking thousands of Watts





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Old 04-09-2016, 20:11   #112
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Re: 12 Volt air conditioner may be availabe soon

Ok let's try looking at this from a different point of view. I am considering the following setup prior to shoving off next spring. Consider this idea. Take a 12 v fridge setup i.e. Fridge boat compressor and evaporater plate and make a chilled water cooler. Seal in a 5-8 gal container with evaporater plate to cool the water antifreeze mixture. Using a small lo volumn pump move chilled water to a small (heater type coil) with a simple 12 v fan blowing over it. Place at head of bed blowing over sleeping area. Running during daylight by solar super chills water so u get a few hrs cool air blowing over u as u sleep. Again typ amp draw 4-5 amps during night for cool air while sleeping. Ok shoot holes in this.


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Old 04-09-2016, 20:20   #113
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Re: 12 Volt air conditioner may be availabe soon

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Originally Posted by Tampabayfireman View Post
Ok let's try looking at this from a different point of view. I am considering the following setup prior to shoving off next spring. Consider this idea. Take a 12 v fridge setup i.e. Fridge boat compressor and evaporater plate and make a chilled water cooler. Seal in a 5-8 gal container with evaporater plate to cool the water antifreeze mixture. Using a small lo volumn pump move chilled water to a small (heater type coil) with a simple 12 v fan blowing over it. Place at head of bed blowing over sleeping area. Running during daylight by solar super chills water so u get a few hrs cool air blowing over u as u sleep. Again typ amp draw 4-5 amps during night for cool air while sleeping. Ok shoot holes in this.


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Wouldn't it be easier to just sleep with your head stuck in the fridge?
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Old 04-09-2016, 20:34   #114
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12 Volt air conditioner may be availabe soon

Chaya,
When designing a system it's important to consider both start-up transients and normal load..... both are important. I.e. Buy a unit that is most efficient when running but also has slow start load.
Wrt start-up loads for a/c units they are typically 1.5 times the normal running load and so breakers, inverters, etc need to be able to take these transients or you'll be resetting breakers a lot.
New technology to the rescue :-)
Soft start or other low technologies allow motors to rev up slowly and so minimize peak amp draw. This means that systems can be sized more closely to running load than the peak start-up load.
Hope this helps a little :-)
Paul



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Old 04-09-2016, 22:54   #115
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Re: 12 Volt air conditioner may be availabe soon

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Originally Posted by GoingWalkabout View Post
You convinced me. So back to the telescopic drawing board.
Chaya,
I've acquired 4inch SS heavy walled tubes about 8 ft long, I will attach plate at bottom with 4inch hole.
However the alternative is to attach to pilothouse instead of aft cabin, either setup will not require recoil for wire in my case. At least at this stage of the project.
In past projects requiring recoils for wires I've used units from portable dish washers. Also recoils for light cords or heavier ones designed for air hose reels. Of course that depending on length and size of what you need to recoil.
Have you found a boat or in design mode?
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Old 04-09-2016, 23:25   #116
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Re: 12 Volt air conditioner may be availabe soon

Quote:
Originally Posted by Catalysis View Post
Chaya,
When designing a system it's important to consider both start-up transients and normal load..... both are important. I.e. Buy a unit that is most efficient when running but also has slow start load.
Wrt start-up loads for a/c units they are typically 1.5 times the normal running load and so breakers, inverters, etc need to be able to take these transients or you'll be resetting breakers a lot.
New technology to the rescue :-)
Soft start or other low technologies allow motors to rev up slowly and so minimize peak amp draw. This means that systems can be sized more closely to running load than the peak start-up load.
Hope this helps a little :-)
Paul



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It does help Paul. Thanks. On a seperate issue, I remember reading years ago that the starter in a fluorescent light draws as much power at start as it takes to run the average light all day. Not sure if it's true or not but that's why I was thinking a soft start would drain less power. But as with a lot of things. Bench or real life testing trumps theoretical everyday.

Thanks a lot Paul.
Chaya
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Old 04-09-2016, 23:41   #117
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Re: 12 Volt air conditioner may be availabe soon

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Originally Posted by newhaul View Post
Look at their page again there is a hose that hooked up to the hot side to vent the warm air outside of the space being cooled.
For every cuft of hot air exhausted from the tent out of that hose, a cuft of air has to replace it, or the tent would collapse from the vacuum.

One guess where that replacement air comes from and what temp. it is.
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Old 05-09-2016, 00:04   #118
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Re: 12 Volt air conditioner may be availabe soon

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For every cuft of hot air exhausted from the tent out of that hose, a cuft of air has to replace it, or the tent would collapse from the vacuum.

One guess where that replacement air comes from and what temp. it is.
Ambient outside air temperature will be lower than the exhaust air, same as with any aircon. Just make sure that it is venting downwind
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Old 05-09-2016, 00:12   #119
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Re: 12 Volt air conditioner may be availabe soon

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Chaya,
I've acquired 4inch SS heavy walled tubes about 8 ft long, I will attach plate at bottom with 4inch hole.
However the alternative is to attach to pilothouse instead of aft cabin, either setup will not require recoil for wire in my case. At least at this stage of the project.
In past projects requiring recoils for wires I've used units from portable dish washers. Also recoils for light cords or heavier ones designed for air hose reels. Of course that depending on length and size of what you need to recoil.
Have you found a boat or in design mode?
Very useful information thruska. Thank you. Correct me if I'm wrong but I think your talking about the cord recoil also found in hairdryers.

I'm still in the shopping mode mode. Pretty well settled on what I don't want while narrowing down to 3 choices. First I'm set on the Lagoon cats. I love the layouts of owners in the 56 and 62. I don't like the 52 because of bad reports on speed under sail. I also can't get past the ugliness of the mast in the salon. Different if it was a monohull but very out of place on the cat IMHO.

Then there is the tried and trusted L450. Nifty under sail. Stable at sea and the owners layout is nice.

The price difference between new and two or three years old in the 450 is dramatic. So if I chose the baby of the 3 models I would buy 2 or 3 years old. The L560 is really a nice cat. I love the layout. Especially the owners version where you can come and go from the master cabin from a hatch door onto the cockpit. Also the VIP cabin is great as well. The L560 is holding its price better than the L450 but it seems to be harder to sell in the after market. I think it's slow sales compared to the L450 is because it's nearly double the price.

Then you come to my dream boat. The L620. Owners version with galley downstairs. I've even seen models with a jacuzzi in the master suite bathroom. interesting thing is that it's only a 200K or so more than the L560. That is on the previous owned market.

I've been told to cross the L620 off my list because it just too big for single or couple handling. I really don't buy that since I know from my powerboat days many powerboat erst have brought on 60 foot plus vessels single handed. With electric winches everywhere I think it's very manageable. Only issue would be having to manhandle the mainsail if it gets stuck.

Insurance, haul out, bottom cleaning and marina slips charges will be almost 2/3 rd of the much smaller L450. Much larger engines will also burn more fuel. But as in all things even on land if you want to live in a larger and nicer house you pay for it. My biggest concern is the social aspect. I would want to fit in to the local scene whatever marina or port I'm in without sticking out ostentatiously. I think you get the idea.

So all in all I'm coming back to choosing between the L450 and the L560. The L450 has a lot of advantages. Lower profile in not drawing attention to oneself. With the price difference between the L450 and L560 I could take that money and buy my onwards slip or slips. While also upgrading with all the stuff I really want like a solar system to kill for and that amazing Flur rotating very long distance night vision camera. Also a jet tender would be great as well.

I may reverse myself and just go ahead and buy new either the L450 or L560. The next 6 to 8 months I plan, all things going well, to make my final decision. Much will depend on what I also choose to do with my business interests. I could very well see entertaining business associates on the L620 both on the east coast of the USA and using it as a base while doing business in Europe.

So many issues to think about. In the meantime I'm learning as much as I can on all the systems onboard. Such as how best to set up the solar. One way or the other I plan to take the plunge early next year (if not sooner). Using the time now to learn, learn, and learn more.

Regards,
Chaya
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Old 05-09-2016, 00:22   #120
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Re: 12 Volt air conditioner may be availabe soon

Quote:
Originally Posted by GoingWalkabout View Post
It does help Paul. Thanks. On a seperate issue, I remember reading years ago that the starter in a fluorescent light draws as much power at start as it takes to run the average light all day. Not sure if it's true or not but that's why I was thinking a soft start would drain less power. But as with a lot of things. Bench or real life testing trumps theoretical everyday.

Thanks a lot Paul.
Chaya
According to many sources, including the US Dept of Enegy:

The amount of electricity consumed to supply the inrush current is equal to a few seconds or less of normal light operation. Turning off fluorescent lights for more than 5 seconds will save more energy than will be consumed in turning them back on again.

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