12 DC Air conditioning

Hi everyone...
Does anybody has experience or opinions with a 12V DC air conditioner made by Glacier Bay. The unit is the DC breeze, with a capacity of 5,000 btu and a power consumtion of 48 amps at full blast.....

The unit is to be installed in the aft state room, for those times in anchor....

Best regards to alll

Ismael

12 volt a/c

Gee Ismael, I hope you have a generator for this one. For a 48 amp per hour draw for a hot 8 hour period, (and I'm assuming you will only use this on hot days or nights) is over 380 amps! Add in about 100 amps of normal daily lighting, fresh water pumping, radio etc. and you will need a battery bank of about 1000 amps, assuming a 50% maximum discharge plus a spare to start the engine when you run the air for 10 hours. Given a 1000 amp hour battery bank, ( ten group 27 batteries, plus the starter battery) the next problem is recharging the bank, because a 55 amp alternator would take forever. There are also compressor units that will run off the engine like automobile units, but these only work when the engine runs, so it comes down to either a 110 volt air unit (I have one) only good at the dock, or another type with a generator. Ernie Schlesinger

12V DC air conditioner

To Ernie,
Thanks for your reply. I had the feeling the idea was impractical, unless I use it only a couple of hours to cool thins a bit and then use the regular 12 volt fans. Battery technology has not evolved much since early 1900's .
What is considered a robust battery bank..??? The boat I just aquired (E-38) has I think two group 27 as stock option, and the previous owner installed two additional group 35(???) behind the engine. I think the combined banks are good for around 400 amps/hr..?????

Ismael

Ac ?

http://www.dcbreeze.com/finding_power.htm

Their battery reccommendations are interesting. It still looks like you would need a quite powerful charging and storage system when you are away from shorepower.
As to how many amphours is "enough" for you own situation... you will really have to do some amp hour consumption math for your particular lifestyle.

We have about 240 AH in a house bank of two large golf cart batteries, and this runs our 12 volt fridge for two days at a time when at anchor. However... 1) we boat in the NW where ambient temps are moderate, 2) our ice box is small, and 3) we installed the Frigo Boat "keel cooler" system for optimal efficiency.
Future thought: If we install a forced air furnace, the house bank will probably need to be enlarged... again...

Re-creating all the comforts of home, utility wise, when afloat in a corrosive environment, is a constant challenge!


Best wishes for cool breezes,
Loren in PDX

DC breeze, and other high voltage topics..

Thank you , Loren, for your response regarding the DC air. I'll keep the DC breeze on the back burner and focus on installing a regular A/C, as it is hot and humid in the marina.

Regarding marinas and shore power, the boat is US-made, for the UK, so the AC system is 230 V/60Hz. So, in therms of appliances...I think I have various choices:
1. Get 230 volt appliances, (mainly a small microwave and a small flat panel for the main salon).
2. Get 120 V appliances, and good quality transformers.
3. Convert the AC system to 120 V.
4. Get a high quality 2-3Kw inverter, and a couple of 120 sockets. That would be nice if anchored away....

The inverters I checked (Xantrex) are either 120/60Hz, or 230/50Hz.

I am tempted to go with 2 & 4.

Ismael

S/V Erica of Falmouth
E-380

If you were planning to install the Glacier Bay refridgeration, getting the adaptation kit for air conditioning could be viable financially. Bear in mind you will need a 48A battery charger to run it continuously a the dock. Otherwise, what most folk in the heat of a Pensacola summer install is a regular $250 wall air conditioning unit from a home supply place, and rig it into the top or companionway hatch with plywood or foam insulation.

It is not practicable to run air conditioning on a boat without being plugged into shore or running an engine.

A transformer is probably your best option for your AC system, a lot cheaper than the inverters. To run much equipment at anchor involves more batteries than are easy to fit on a sailboat - although some do it.
Gareth
Freyja E35 #241 1972

Air conditioning

You probable have 2 group 27's total 210 amps and 2 group 31's totaling an additional 250 amps. Assuming you use one of the 27's as a starting battery, this leaves you with about 355 amps for the house bank. This gives you a usable discharge capacity of no more than about 175 amps. Of course your batteries will never be charged to 100% except when you are in the slip and on a charger. Engine charging almost never gets you back to 100 %. This is adequate for most sailors. However it is not great mixing sizes and types as some batteries may more charge than others. Ernie Schlesinger