Compressor Refrigerator opt 12v?

I have less battery space than you do. I'm hard pressed to run 2 Group 27's in my pop up, just no room. I think I'll stick with plan B and get a cool box for the backseat of the truck and call it good. Heck, my truck has 2 group 31's under the hood.

I guess the solution is 300 watts or so of solar and 300 AH or so of batteries. Neither work very well with my Northstar Igloo. I had to remove the battery tray and can barely fit 2 Lifeline 150 AH AGMs. I have room for two 135 watt solar panels. A third or fourth would definitely help but room is limited with a Heki skylight, bath vent, bath skylight, a power vent, plumbing vent, A/C and a monstrous old style TV antenna. I am strongly considering junking the antenna and adding another panel. In 7 years we have never even checked to see if the TV works.

Of course, the other consideration is shade. Even minimal shade kills solar panel output. A great many campgrounds are in the shade in wooded areas. Camping in the Fall, Winter and Spring can also mean the sun is low and with short days the solar output is poor. Should I mention clouds? Or trying to use the furnace. I was running through a propane tank every couple of weeks with temps below freezing at night and often in the 50s or lower during the day. The furnace blower really kills the batteries. I am really sick of running the generator to compensate for these issues. I have an older electrical system and the generator charging is slow and inefficient. Next upgrade with probably be a new charging system.

Count me as another happy NovaKool 12V compressor refridgerator user.

I replaced a poorly-functioning (and old) 4CF Dometic with a 5.8CF NovaKool in the spring of 2013. I have had zero issues with it since. I bought the 12V only model as I already have a 12V to 120V converter in the camper. The NovaKool was a little shorter so I had to add a filler board above it, while being 1.8CF bigger on the inside. It was also much lighter. I didn't weigh either one, but lifting them the weight difference was very noticable.

I have 400W of solar and 320AH of battery to run the fridge, an Engel 12V compressor cooler, this computer, and everything else in the camper. The batteries can go up to 3 days with little to no sunlight, but I get unhappy after 2 days.

JimK-NY wrote:
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.

Our NovaKool 7.5 used 4.2A when cycling as per amp metre. Your calculation of 60AH per day is correct in our experience when the days were warm to hot, nights down to 65F. But if we were camping "at this time of the year", the temps would be much lower and as we tend to shut off our furnace all night and rely on thick quilt for warmth turning furnace on in the morning for short periods and on 55F when we were out in the day, the fridge would hardly even cycle so 20-30AH days for the fridge in the fall and spring would be quite common. Because we dry camp almost 99.5% of the time and choose not to run our genie if possible, having as small an electrical power footprint as possible and still keep comfortable and not discharging the batteries below 50% is always a challenge but it is very doable. If you doubt our camping style, check out the trip reports in our blog.

We orginally started with 190W of solar and 4 AGM batteries and found when the weather got warm to hot, our solar stuggled to keep up. Added another 140W for 330W total and never looked back.

As the 12V compressor fridge was the largest user of electricity from the batteries in our case, I would recomment 2 batteries and 200W of solar just to power the fridge if you wanted to opperate with some independence from a genny or shore power, (A/C excluded).

One thing is for sure, each of our power usage is different from camper to camper. For example, your wifes 30AH /day CPAP usage is more than we would normally consume for all of our daily electricity use minus the fridge.

We have sold the TC and now have a TT with a 6cuft propane/120V fridge. It works fine but if it ever fails, the 9200 NovaKool(9cuft) will fit perfect in the same spot and I already have enough solar and batteries.

Our experience with the 12V compressor fridge has been very different than yours but thanks for an honest evaluation of your situation.

Dave

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.

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

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.

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.

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.

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.