Freezer/Refrigerators, portable

smckean (Tosca)":3klurxcg said:
I just had a Victron installed. I'm very happy with it.

Thataway, I looked at that $19 meter link. Certainly is cheaper, but it seems to have a fatal flaw; to wit, if the current reverses (that is, even a short burst of charge such as when you briefly start your engine and the batteries charge briefly), the meter resets itself to zero. At that point you have lost any data as to how many amp-hours you have used. With the Victron, one can also watch the amps flowing back into the battery to see how you are doing in the struggle to replace the amp-hours you used. Again, I take comfort in knowing that I've used, say, 25.6 amp-hours since I was last at 100%, and now that I'm charging, I can watch that negative number melt away amp-hour by amp-hour toward zero.
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Not entirely correct from my understanding: If you reverse the flow thru the shunt, it will reset the meter to zero. But if the charging circuits bypass the shunt, it does not reset. Ie: if the negative lead from the battery charger or solar panel go directly to the negative terminal of the battery--the meter keeps reading current outflow. It all depends on what you want to do, and how you manage the battery. For example in my case, I use a 30 amp battery charger driven by the Honda EU 1000I. If it resets, that is fine, since I have read the information before I start the generator. In fact that is my criteria for charge.
There are other flaws--such as the manual reset, and not being waterproof. But I manually reset, since I don't put any charge current thru the shunt.

If I was buying new now, I probably would buy a Victron 702, temperature is useful if you are "pushing" the charge into a battery, and on my RV, there is a temperature sensor, and that feeds back into the charging circuit (charger is capable of 110 amps). A temperature sensor protects the battery from getting too hot. The 702 with temp sensor is going to be about $70 more than the 700. If you wish can read the voltage off the start battery in a number of other ways. My Link reads start battery voltage. If you are running the electronics off the start battery (not recommended), you can read the temp off most MDF's.

If one wanted to use separate instruments to measure current in and out at a specific time, this may be more useful than the single Victron. You would have to wire the second shunt differently to get current in. If the Victron is similar to my Link, you read "net current flow"--that is current flow in less current flow out. For example, you charging source may be putting in 10 amps, and the freezer is drawing 5 amps, you will read a net of 5 amps charging current.

The Vectron is a far better instrument, and what i recommend for most folks. However, I use an isolated battery/bank, for my refer/freezer.
 
So the freezer cost us 10.5lbs and centralized our mass a bit better.

-we replaced the cockpit coolers with smaller models knowing we would save space on ice from now on.
-we used to carry 3 gallons of extra water in the under berth bow section but now only carry one.
-we are using 15 half liter waterbottles in the freezer to act as ice blocks which do double duty replacing two of the gallons carried in the bow.
-we also added some solar charging which added 8lbs but I consider that to be an optional addition depending on use patterns



freezer.sized.jpg

Greg
 
Heck Greg,
Some of us just keep adding stuff to our boats and never take things out....

I never figured the weight--but with the two Dometic DF 50's, plus the extra battery, I think it is less than our largest ice chest, but then there is the generator and gas.... But who knows?
 
Just picked up a National Luna Twin 60 for a Four Wheel Camper that is on order. I'm going to use this in the CD22 as well. 40 liter fridge and 20 liter freezer with dual readouts. This thing is built way nice and was way expensive. If I were going to buy 2 seperate units then it's a close call. The nice thing was the importer is in Salt Lake City so no freight. He has a warehouse full of them. It uses the Danfoss compressor and the average draw is 1.53 - 2.6 amp/hour. They make full use of the 3 speed compressor, has the turbo mode and you can set the battery cutoff. If anyone is anyone is interested I have a slightly used Engel with the cover for sale PM me. It might take a little of the sting away. One of the things that I liked about the Luna was it can be used as Fridge/Freezer, Fridge/Fridge, or Freezer/Freezer.
 
At the complete opposite end of the spectrum is the Coleman Power Chill. I used ours at Lake Powell this year. I bought mine in 1999 and it has been around. I took it to the Australian outback once (as a piece of luggage filled with clothes) and it hasn't been pampered over the years. Cools enough to keep produce for 10 days. Extravagant items like fresh meat and cold beer aren't possible, but for under $100 and 17 years of service, I'm not complaining. My 50W solar panel just barely keeps up with it, so it draws about the same as the fancy freezer.

Mark
 
The best your going to do with thermoelectric is 40 degrees below ambient temperature so when it's 90 degrees at Lake Powell your going to get 50 not even close to the temps you need to store food. In refrigeration applications, thermoelectric junctions have about 1/4th the efficiency compared to conventional means (they offer around 10–15% efficiency of the ideal Cannot cycle refrigerator, compared with 40–60% achieved by conventional compression cycle systems (reverse Rankine systems using compression/expansion). Due to this lower efficiency, thermoelectric cooling is generally only used in environments where the solid state nature (no moving parts, low maintenance, compact size, and orientation insensitivity) outweighs pure efficiency.
 
I agree wth Jay about the thermoelectric (Also known as Peltier–Seebeck effect.) coolers. Even with 3" insulation total seal foam,vapor barriers, I did not find it cooled enough to be a real source of refrigeration. Yes, it will keep vegies--but so will evaporative cooling--and be close to the same temps...The 40 degrees is the best it will do--and in reality usually closer to 20 (I did a lot of experimentation with these, since I thought it would be ideal for the 38 foot boat we built back in 1979. My primary cooling in this were Dole eutectic holding plates run by an engine driven compressor. The Peltier unit worked OK in temperate and cool temps. But in the tropic even to get the beer cold, we used the holding plates. Not a substitute for a compressor refrigeration unit.

Jay Wow! That is the real Ferrari of freezer/refers! Got the highest ratings of all of the units. Should be fantastic. You are going to love it!

I have not mentioned much about a similar unit, but the Kia of this type of unit. I bought the Whynter 62 Quart Dual Zone Portable Fridge, slightly used and with a small dent in the lower case--plain steel, and Chinese dual compressors. It also has two compartments: either of which can be a freezer or refrigerator. We used it for a month on the Mississippi. The question was comparison with the Dometic 50 quart unit we have been using--or rather with the two 50 quart units--would it be enough?. One thing we noticed, is that the compartment, stepped up (higher temp in the Dometic), was at the same temp as the rest of the compartment--and so it gave more really cold space. So far the dual zone unit has worked very well. The current draw was very close to that of the 50 quart unit. It's a keeper. We just don't know how long it will last. We also would keep it out of the salt spray, since I am sure the case will rust.

Will we give up the Dometic? No It works great in the car--and we still will carry it on long trips. But the 62 quart dual, was fine for a month! Our extra Dometic will go to our son.

Great score Jay!
 
jkidd":160aeqlk said:
thermoelectric cooling is generally only used in environments where the solid state nature (no moving parts, low maintenance, compact size, and orientation insensitivity) outweighs pure efficiency.
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My application exactly. I do have to forego icecream bars for a week, but I can do that. Actually, they sell them at Dangling Rope if I were suffering from withdrawal.

I was tempted to go without refrigeration, but I really enjoyed a big salad every night. 40 degrees below ambient, even when we had 90 day temps, was enough to keep the produce in good shape. A wet towel on the cooler really helps.

Mark
 
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