Compressor Refrigerator opt 12v?

[joe_julie81]

Has anyone been using one of these 12v compressor refrigerators? I've heard they are low amp drawing. How are they on the battery?

[JimK-NY]

I don't doubt your facts either, but some calculations are in order. The larger Nova Kool units use the larger Danfoss compressor set at about 5 amps. If your unit does great and only runs about half time, that adds up to at least 60 AH per day. At this time of year at 37 degrees latitude, 200 watts of solar can only generate a maximum of 50 amp hours per day in full sun, all day with no clouds! (Source: http://www.where-rv-now.com/Notes/Solar/index.php) You are going to come up way short almost everyday and that does not include any other use of electricity.

[dave17352]

JimK-NY wrote:
I have a Northstar with a compressor refrigerator. When I bought the camper it came with a large unit, about 7 cu ft. The wiring was not done correctly. The refrigerator was on the other side of the unit from the batteries so the wiring length was pretty long. Northstar used 12 gauge wiring which barely worked. When the battery drained slightly, the drop in voltage due to the undersized wiring was enough that the refrigerator shut down. Next Northstar failed to provide adequate ventilation. There was some intake under the unit but the exhaust was merely a 3" diameter hole. Very substantial ventilation is required for a 7 cuft refrigerator. In addition is probably pulled about 6 amps. I replaced with 12 gauge with 6 gauge wiring, put in a lot of ventilation and then gave up on the large unit. I replaced the Waeco with a small 4 cuft NovaKool. Power consumption dropped to about 3 amps. I also added a second 135 watt solar panel and 300 AH of AGM batteries. The upgrades cost me about $1000 for the NovaKool, another $500 or so for the solar panels and installation and $800 for the batteries.

As I mentioned the NovaKool pulls about 3 amps. In cool weather, say 70 degrees, it only runs about 30 percent of the time for about 20 amp hours. In the summer when temperatures often exceed 80 degrees, the unit runs almost constantly and by 85-90 it does run constantly for a consumption of about 70 AH. On average I probably need to replace about 50 AHs per day. My wife also uses a CPAP that pulls another 30 AH. Charging computers and camera batteries and minimal use of the water pump and LED lights can easily add another 20, 30 or more AH. I routinely use 100 AH per day. I just completed a 3 month trip. At this time of year in most latitudes, the solar panels cannot possibly keep up with the consumption. I avoid shade, hate cloudy days and am constantly paying attention so I park for maximum solar gain. Virtually every day for the past 3 months of travel I had to run the generator for an hour or two in the attempt to break even and avoid shortening the life of my batteries.

Would I get a compressor refrigerator again? Absolutely not. I am even thinking of cutting holes into the side of my camper so I can install a propane unit. If you think I am negative about compressor refrigerators, read this story about trying to deal with a compressor refrigerator in hot weather:

https://www.exploroz.com/members/145028.75/1/2009/queensland_adventures_winter_2008.aspx?p=%2fblogs%2fdefault.aspx

So unfortunate that you have had all these problems. I have a 7.5 foot nova kool and it works fantastic. It has zero problems cooling at 100 degrees. I don't doubt your account at all. I just feel something is wrong, out of the ordinary. I would have to say from what I have read on the internet that about 99 percent love their compressor fridge and would never go back to propane. I have 2 105 amp hour agm's and 200 watts of solar and have no problem keeping things charged. If I was going to venture out on a 3 month trip planning on boondocking most of the time I would have a small generator to charge the batteries if needed.

I can see in a cool climate with low amounts of sunshine and boondocking a propane fridge could be the choice. But sunshine and heat I would choose a compressor fridge every time. JMHO

[SidecarFlip]

Kayteg1 wrote:
Side observation - most of us have access to WI-FI on the road.
About $40 buys you a thermometer with probe that will send alarms to your cellphone.
I bought one for my dogs, but figure out putting probe inside refrigerator is icing on the cake.

The Accurite digital remote thermometer is 10 bucks at Wal mart and I just keep the digital readout in the cab when driving. Works fine.

My cellphone stays turned off and in the console when I camp. I don't need or want it on... I'm camping, not communicating.

[SidecarFlip]

JimK-NY wrote:

Wankel7 wrote:
JimK

Since you downsized would their be room for insulation? This reseller claims a large reduction in power if you add additional insulation.


http://www.backwoodssolar.com/novakool-dc-refrigerator-model-r5810

I was able to add 2 inches of dense foam. I also added 2 computer fans to provide a flow of air across the condenser. I only turn the fans on during hot weather. The difference in power consumption as the ambient temperature increases is really remarkable. An increase from 70 to 80 degrees will more than double the power consumption. I bought the unit new and I don't think there is anything wrong with it. I have had the unit stop working on several occasions. To restart I have to pull the fuse, reinsert the fuse and then turn the unit back on. Unfortunately I usually fail to detect the issue immediately and often have a pretty warm and defrosted unit by the time I discover the issue. I contacted NovaKool and have still not been able to identify the cause. I suspect it is due to the unit turning on at the exact time the furnace or water pump starts up, but I am only guessing.

On my ammonia unit, I run my fans on an adjustable snap disc thermostat (available on Amazon) for about 10 bucks, adjustable to any on of temp you want the fans to run at.

[Kayteg1]

Side observation - most of us have access to WI-FI on the road.
About $40 buys you a thermometer with probe that will send alarms to your cellphone.
I bought one for my dogs, but figure out putting probe inside refrigerator is icing on the cake.

[JimK-NY]

Wankel7 wrote:
JimK

Since you downsized would their be room for insulation? This reseller claims a large reduction in power if you add additional insulation.


http://www.backwoodssolar.com/novakool-dc-refrigerator-model-r5810

I was able to add 2 inches of dense foam. I also added 2 computer fans to provide a flow of air across the condenser. I only turn the fans on during hot weather. The difference in power consumption as the ambient temperature increases is really remarkable. An increase from 70 to 80 degrees will more than double the power consumption. I bought the unit new and I don't think there is anything wrong with it. I have had the unit stop working on several occasions. To restart I have to pull the fuse, reinsert the fuse and then turn the unit back on. Unfortunately I usually fail to detect the issue immediately and often have a pretty warm and defrosted unit by the time I discover the issue. I contacted NovaKool and have still not been able to identify the cause. I suspect it is due to the unit turning on at the exact time the furnace or water pump starts up, but I am only guessing.

[Wankel7]

JimK

Since you downsized would their be room for insulation? This reseller claims a large reduction in power if you add additional insulation.


http://www.backwoodssolar.com/novakool-dc-refrigerator-model-r5810

[SidecarFlip]

An interesting trip report, I read the entire essay. After reading that, my logical choice would be a Dometic Cool box for the backseat of the truck and keep the 3 way where it is.

My big issue is getting level (within 1/2 bubble fore and aft) in many places where we 'bush camp'...I like that term. The ammonia fridge likes to be level, front to back, not so much side to side. I can see why you would prefer an ammonia unit over a compressor. I know mine, even with 2 auxiliary fans only pulls 1.5 amps (when the fans are running, which isn't all the time) and less than 2/10th of an amp when not running.

[JimK-NY]

I have a Northstar with a compressor refrigerator. When I bought the camper it came with a large unit, about 7 cu ft. The wiring was not done correctly. The refrigerator was on the other side of the unit from the batteries so the wiring length was pretty long. Northstar used 12 gauge wiring which barely worked. When the battery drained slightly, the drop in voltage due to the undersized wiring was enough that the refrigerator shut down. Next Northstar failed to provide adequate ventilation. There was some intake under the unit but the exhaust was merely a 3" diameter hole. Very substantial ventilation is required for a 7 cuft refrigerator. In addition is probably pulled about 6 amps. I replaced with 12 gauge with 6 gauge wiring, put in a lot of ventilation and then gave up on the large unit. I replaced the Waeco with a small 4 cuft NovaKool. Power consumption dropped to about 3 amps. I also added a second 135 watt solar panel and 300 AH of AGM batteries. The upgrades cost me about $1000 for the NovaKool, another $500 or so for the solar panels and installation and $800 for the batteries.

As I mentioned the NovaKool pulls about 3 amps. In cool weather, say 70 degrees, it only runs about 30 percent of the time for about 20 amp hours. In the summer when temperatures often exceed 80 degrees, the unit runs almost constantly and by 85-90 it does run constantly for a consumption of about 70 AH. On average I probably need to replace about 50 AHs per day. My wife also uses a CPAP that pulls another 30 AH. Charging computers and camera batteries and minimal use of the water pump and LED lights can easily add another 20, 30 or more AH. I routinely use 100 AH per day. I just completed a 3 month trip. At this time of year in most latitudes, the solar panels cannot possibly keep up with the consumption. I avoid shade, hate cloudy days and am constantly paying attention so I park for maximum solar gain. Virtually every day for the past 3 months of travel I had to run the generator for an hour or two in the attempt to break even and avoid shortening the life of my batteries.

Would I get a compressor refrigerator again? Absolutely not. I am even thinking of cutting holes into the side of my camper so I can install a propane unit. If you think I am negative about compressor refrigerators, read this story about trying to deal with a compressor refrigerator in hot weather:

https://www.exploroz.com/members/145028.75/1/2009/queensland_adventures_winter_2008.aspx?p=%2fblogs%2fdefault.aspx

[sabconsulting]

I've been running a Waeco 140 litre compressor fridge for 6 years.

When the compressor runs (cuts in and out depending upon the temperature) it draws about 6 amps (at 12v). In hot weather it could be running 50% of the time or more. When I have hookup the fridge will switch to running off mains instead to preserve battery power.

I love that I can park anywhere however unlevel and the fridge will work. E.g. when hiking in the hills and mountains we rarely find anywhere level to park.
I also like that it gets down to temperature quickly and stays there.

I have 160w of solar and 1 AGM battery. I recommend at least 2 batteries. With a compress fridge you need to keep an eye on your battery usage. Remember that even with solar your fridge is draining your battery over night or when parked in the shade or on cloudy days since there will be no appreciable power coming from the solar panels.

If you want to stay camping in one location for several days without hookup, a generator or plenty of direct sunshine on solar panels, you will need to be pretty careful about monitoring battery state.

Other things to consider: Being that it has a compressor we can just about hear ours running over night. It doesn't disturb me, but I am aware of it.

Steve.

[Wankel7]

It would be great if more truck camper builders would include this as an option. It seems Northstar offers it and that is about it.

Include the option to delete the roof vent and shrink or eliminate the outside wall vents if going with a compressor fridge.

[Kayteg1]

There is no "one idea fits all" in RV.
I do have solar panel that is turning 20 years, yet never installed it while camping in CA. We went to the woods and park in deep shade, so no AC needed and spending night at campfire batteries would last for 3 days without generator.
For long stays I had 50' extension cord and I would move the solar to exposed locations
Manu fact, years ago - having 27' ClassA I removed the 600lb generator from it, as I had no use for it and made very nice storage.
The generator got stolen from my storage and witnesses say it took 3 men to load it on flatbed.
Now I moved to NV and camping mostly in AZ, finding ANY shade seems impossible, so installing solar on the roof is my winter project.

[SidecarFlip]

brholt wrote:
Really depends on where you go camping too. I was camping this weekend off highway 20 by Concrete WA. Solar panel did absolutely nothing over the weekend - which is pretty much the story here in Western WA over the winter. We simply can not rely on solar in the winter.

I'm pretty dumb when it comes to solar power and while I read posts on here, I get confused anyway but I have read that a partially shaded panel is basically useless and where I primarily camp, it's just that shady as in forest canopy overhead sop I just use my little genny for a couple hours every day to charge the batteries back up and all is good.

I have a direct charge port on my unit that bypasses the converter and I can direct charge them.

[brholt]

Really depends on where you go camping too. I was camping this weekend off highway 20 by Concrete WA. Solar panel did absolutely nothing over the weekend - which is pretty much the story here in Western WA over the winter. We simply can not rely on solar in the winter.

[SidecarFlip]

DWeikert wrote:
I'll just chime in and say I bought my Northstar with the Dometic 12v compressor fridge from the factory. Absolutely no regrets. You will need solar to maintain your batteries unless you plan to drive every day. My primary reason for getting it was I didn't want to have to find someplace level any time I wanted to pull over and fish for a few hours.

I have your issue (the level part) when parked in the woods. Woodses ain't level.....