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Topic: 24hr Battery Drawdown Test (Read 1717 times) previous topic - next topic

Re: 24hr Battery Drawdown Test

Reply #40 –
The Vissani refrigerator has R600a (butane) which is about 20% more efficient than R134a plus lower operating pressure.
R600a is pretty common in Asia on small refrigerators.
Steve

Re: 24hr Battery Drawdown Test

Reply #41 –
Look at the annual estimated power use sticker.  It is a pretty good real world estimate.  Divide by 365 then 24 to get hourly estimate.  Mine was somewhere arround 480 KWHrs/yr as I recall.  About 55 watts per hour on average over a year. About 1.4KW per day.  About right.

Re: 24hr Battery Drawdown Test

Reply #42 –
Hello Tim, I am so glad you are on this forum to keep us in line and bring up the possible.  "Question: Don't residential fridges use 800 to 1200 watts, which would be up to 100 amps from a 12 Volt battery?  This is not what the original post reported."  I believe you are technically correct, except that the defrost cycle is seldom on.  On the average I believe my customers told me their residential refrigerators draw no more than their  rv refrigerators as the defrost cycle seldom ran, the compressor seldom ran, all of this because the residential refer was insulated multiple times what a rv refrigerator was.

Re: 24hr Battery Drawdown Test

Reply #43 –
Most new frostless refrigerators has a sensor that determines when it needs a defrost, it can go days before it needs one depending on use.
Also I'm going on the limb in that ammonia absorption refrigerator will be phase out in all new RV's within 10years. The European's such has Danfoss have  been developing variable speed DC compressors for sometime. The trend is heading for a micro DC compressor in the 24 to 42 volt or 100 to 500 watts depending size of the refrigerator. One company is developing a household refrigerator that only needs couple solar panels and a battery to run year around for countries that don't have a reliable or no power grid.
Steve

Re: 24hr Battery Drawdown Test

Reply #44 –
Quote from: Willy White –
Most new frostless refrigerators has a sensor that determines when it needs a defrost, it can go days before it needs one depending on use.
Also I'm going on the limb in that ammonia absorption refrigerator will be phase out in all new RV's within 10years. The European's such has Danfoss have  been developing variable speed DC compressors for sometime. The trend is heading for a micro DC compressor in the 24 to 42 volt or 100 to 500 watts depending size of the refrigerator. One company is developing a household refrigerator that only needs couple solar panels and a battery to run year around for countries that don't have a reliable or no power grid.
Steve
Danfoss compressors have been around a long time, especially in marine use. Many high end motorhomes in the early 2000's came with 12 volt bay refrigerator/freezers as an option. You can buy them now but the are not cheap. Portable Refrigerator/Freezer | CFX-95DZW | PPL Motor Homes
Lower end rv's that have no solar or generator and a small battery will always require propane for heat and cooking, and in this case a propane refrigerator will probably be the best route.
Pros and Cons of the DC Compressor Refrigerator – Truck Camper Adventurehttp://www.backwoodssolar.com/novakool-dc-refrigerator-model-4500
But on that note, as soon as they start making them in th 14+ cubic foot size, they will probably become standard on high end motorhomes

Re: 24hr Battery Drawdown Test

Reply #45 –
Three years ago I replaced my original refrigerator (lost to fire) with a custom "marine" refrigerator that uses two Danfoss 12 volt compressors, one each for the refrigerator and the freezer.  Each compressor draws 4A when running.

Re: 24hr Battery Drawdown Test

Reply #46 –
The frost free part with timer, heated gaskets and defrost can be disabled or put on a switch for dry camping. The fridge schematic will show which wires are used.

Pierce
 

Re: 24hr Battery Drawdown Test

Reply #47 –
Yes Danfoss 12 volt compressor been around a long time, I've repair many of them. Most of the time I just replace the boat refrigerator from Home Depot and install an inverter, much cheaper and work better. (I had a small side by side in my boat).
Anyway the new so call high voltage DC compressor I was referring too will operate with a newly developed high pressure (earth friendly) refrigerant for an efficiency much greater than today. Also within 10 years or so  Battery technology and solar panels will have greater efficiently and at a lower cost, so I standby comment that absorption systems well fade away like the Fax machine, well at least IMHO :)
Steve