12 Volt air conditioner may be availabe soon

[a64pilot]

My 16K draws 11 amps at 120 V so of course 110 at Battery voltage, but OK we will go with your 56 for argument.
If you run it for 10 hours then of course that is 560 AH you will have to replace, assume 100% efficiency to keep math simple.
So how many KW of Solar do you have to have to make on average 560 AH?
I don't know or I would throw out a number.

I'm going to swag that to make Solar AC viable, your going to have to have 2 to 3 KW, but that is a swag.


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[GoingWalkabout]

Originally Posted by svGenesis

The only example i have (where i got the idea) was an RV with a 10000 btu ac unit running off of Life-PO, their draw was 56 amps. thinking maybe a 5000 or 6000 btu would draw less. thus being practical to use for sleeping in warm climates.

I think you are on the right track. LifePo4 and a 5000 BTU air con. Very important. You must have a soft start set up for the air con. At least a third of its power drain comes from the initial start up period. If you have a cat you can put 6 X 325W panels. You can buy off the shelf single L battery pack of 1,000AMP 12V or you could string a group of 100 AH Litho to get easily 1,000 AH.

With the soft start being set up properly and say even a timer to shut off after say 5 hours when your in deep sleep would be feasible for us addicted to creature comforts.

[a64pilot]

Soft start does not decrease electrical consumption, just spreads the spike out over time, draw is the same.


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[GoingWalkabout]

Originally Posted by a64pilot

Soft start does not decrease electrical consumption, just spreads the spike out over time, draw is the same.


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Not wanting to get into an argument but I think you'll find that by eliminating the big start up spike you will conserve a lot of energy. As an illustration. And illustration only. In a car if you slam your foot on the gas when taking off you will burn a lot more fast "energy" then if you slowly stepped on the gas.

[jackjb53]

I would love to see a truly capable 12 volt air conditioner, but reading the specs on this...I could do as well with a cooler full of ice and a 12 volt computer fan. And that could also keep the beer cold!

[a64pilot]

Originally Posted by GoingWalkabout

Not wanting to get into an argument but I think you'll find that by eliminating the big start up spike you will conserve a lot of energy. As an illustration. And illustration only. In a car if you slam your foot on the gas when taking off you will burn a lot more fast "energy" then if you slowly stepped on the gas.

You don't get rid of the spike, you spread it out over time, if it were more efficient, then energy star appliances would be built this way, don't you think? If you pull 10 amps for one second or 1 amp for ten seconds, energy consumption is the same, the rate changes, but not the total.



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[a64pilot]

Originally Posted by jackjb53

I would love to see a truly capable 12 volt air conditioner, but reading the specs on this...I could do as well with a cooler full of ice and a 12 volt computer fan. And that could also keep the beer cold!

They make this for airplanes, it works, but you go through a large bag of ice in 20 min. I know as we have one for me to use test flying a certain model of aircraft we make that has no AC, and doing ground run ups in Summer is murder.

http://www.aircraftspruce.com/catalo...clickkey=34881


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[StuM]

Originally Posted by GoingWalkabout

Not wanting to get into an argument but I think you'll find that by eliminating the big start up spike you will conserve a lot of energy. As an illustration. And illustration only. In a car if you slam your foot on the gas when taking off you will burn a lot more fast "energy" then if you slowly stepped on the gas.

A soft start doesn't reduce the total Watt hours consumed on startup, it just spreads them out over a longer timespan, so the peak Watts required is less.

Actually, since no system component is 100% efficient, in practice adding a soft start to a system will use more energy.

[capngeo]

I have a 28' boat... I have an 11 THOUSAND BTU AC... In Florida in the summer it just barely gets the boat to 85°F...... 11 HUNDRED BTU's wouldn't cool a sleeping bag!

[Rorzech]

You'd be better off with an underwear lined with IV tubing that's got cool water flowing through it from a your 500 BTU chiller. With quick connectors so you can be mobile. You could set the temp you want by adjusting the flow with a valve. Or make a simple cooling blanket the same way. You could make a chiller from a few 12 Volt thermopiles you see in coolatrons attached to those big heat sinks that they are glued to.Make it efficient with a small muffin fan that uses almost no power. Sweat like a pig or stay cool as a cucumber, It's your choice. What I'd give to lay on an ice cold blanket on a 100 degree day with 90% humidity. If I was in a situation like that ,I would already have one .But I'll whip one up in an afternoon when I decide to head to warmer climates. Oops, I mean two of them LOL.

[poppyduc]

Really hope it does work In northern Queensland on those hot steamy nights anything in the boats bedroom would be better than nothing.

[SV THIRD DAY]

Originally Posted by poppyduc

Really hope it does work In northern Queensland on those hot steamy nights anything in the boats bedroom would be better than nothing.

There are so many cheap...tawdry jokes that I could make here, but I'm going to show some self-restraint and let my mind go into the gutter not...ha ha ha...

[poppyduc]

yes we have 18000btu on our 38ft and have to close off everything to get a result.
However you have a good point on the sleeping bag idea if you could enclose a small area around the berth and use it just on those steamy night to get a cool few hours of sleep????

[Panope]

How about a duct (from a tiny A/C unit) directly into a sleeping bag? Maybe something like a portable cooler compressor? It sure would feel strange crawling into an arctic rated sleeping bag on a 90 degree evening!

Another idea would be to line a sleeping bag with some sort of 'high thermal mass' material and put the whole sleeping bag into an Engel cooler during day. Might stay sorta cool for the first hour or two of sleep

OR chill water during the day (with solar power) and then pour this cool water into an inflatable sleeping mattress just before bed.

Ridiculous brainstorming session/ OFF.

Steve

[GoingWalkabout]

Originally Posted by StuM

A soft start doesn't reduce the total Watt hours consumed on startup, it just spreads them out over a longer timespan, so the peak Watts required is less.

Actually, since no system component is 100% efficient, in practice adding a soft start to a system will use more energy.

I do believe you both are correct. Thanks.

Ok. Another solution is to have a second diesel generator at around 5KW. Have it connected to a separate stand alone for the main cabin. Run it all night. Depending on the cost of fuel.ut should cost somewhere between $6 and $9 each night.

Or set up your own large solar plant on board using high powered panels and a good Litho setup. Draw power from your 1000AH plus battery pack during the night and recharge early in the morning with the genset, run your water maker, hot water and when the sun is up shining well let your solar panels finish the power download into your Litho batteries off. Don't forget Litho.recharges much quicker than lead. Also since you should have some very large battery bank I would throw in a larger than normal alternator.

A hybrid power source system I think on reflection would be the best. You know you could give yourself carbon credits for the solar power you are generating which should balance out the diesel you are burning.

It's good to brainstorm solutions. I know I would love to have the best way to do this. I hate humidity.