Furrion 12v Fridge battery usage

[SantaFe big sky]

I inquired with Furrion on the recommended battery bank for boondocking with their 10 cu.ft. 12v fridge. I have two Trojan 225 amp 6 volt batteries and will be using a 200w suitcase solar To recharge when camping off grid. Based on their reply I should be good for a week at least.

Here is their fairly detailed reply.
********************
Good Afternoon.

Thank you for contacting Furrion customer support. Congratulations on the order of your new Cherokee.

The amount of time the refrigerator will run in off-grid mode does depend on your battery set up. On a fully charged 100amp hour 12 volt battery it will run for two days based on a 70 degree ambient temperature. On two fully charged 120amp hour 6volt batteries wired in series it will run for five days based on that same 70 degree ambient temperature.

The refer is a 12v system into a 12v in branch circuit. Needs a minimum 15 amp circuit. There is a 15amp fuse in the rear of the unit that allows for hookup to a higher circuit in case you desire to connect with a combination of items.

Hope that answers all of your questions, but if not please feel free to reply with anything else I can assist you with.

Thank you and have a great day.

[babock]

So...50A per day which is what I always thought they would use. Not sure I would run a 100A lead acid battery to a 100% discharge though.

[Uno133]

Two questions I have
1) will a 100 w solar suitcase charge a battery enough per day to run it on propane?
2) on the prewired furion 10 amp plug on my TT is there an in-line fuse and if so where?

Thank you. I am new to solar and TT.

[AlaskaErik]

Originally Posted by Uno133

Two questions I have
1) will a 100 w solar suitcase charge a battery enough per day to run it on propane?
2) on the prewired furion 10 amp plug on my TT is there an in-line fuse and if so where?

Thank you. I am new to solar and TT.

You're talking about about an absorption type refrigerator, which typically can be run off of propane or 120 volts, and occasionally off of 12 volts. But they do not have a compressor. The are known as 2 way (propane, 120 volt) or 3 way (propane, 120 volt, 12 volt) refrigerators. This discussion is about 12 volt compressor refrigerators, which have a much higher current draw. An absorption unit only uses a small amount of current for the PC board, assuming you have a more advanced unit with a PC board, which is most of them today, although my KZ refrigerator requires no battery power when running on propane as it has no PC board. A 100 watt solar panel is more than enough to run only an absorption refrigerator. The question is, what else is the battery powering? But the more important question is, do you have an absorption refrigerator or a 12 volt compressor refrigerator?

[Uno133]

Alaska Erik thank you for the response. I have a 6 cu ft Norcold AC/LP gas absorption refrigerator. Other electric use includes interior lights used sparingly as well as the water pump also used intermittently. In the fall we will use the 13500 btu furnace in Michigan.

We tend to camp in places without electricity. My hope is that the 100w solar panel will keep my battery charged to an acceptable level. I have a generator that I bring but I have a desire to not use it if possible.

[wanderingbob]

The Furrion 12 volt is compressor driven .

[Flybob]

I am a little skeptical of the factory's math. On two fully charged 120amp hour 6volt batteries wired in series it will run for five days based on that same 70 degree ambient temperature.

Drawing the batteries down to 30% gives you 84 AHr or roughly 17AHrs per day ( for a 5 day trip) Assuming the fridge runs 15% of the time. It implies that it only draws 4.7A. Factory spec says Input power rating: ≤ 15A (11A @ 12V DC)
Your mileage may vary.

[babock]

Originally Posted by Flybob

It implies that it only draws 4.7A. Factory spec says Input power rating: ≤ 15A (11A @ 12V DC)
Your mileage may vary.

That's average current per hour. They don't run 100% of the time

[bikendan]

Originally Posted by Uno133

Alaska Erik thank you for the response. I have a 6 cu ft Norcold AC/LP gas absorption refrigerator. Other electric use includes interior lights used sparingly as well as the water pump also used intermittently. In the fall we will use the 13500 btu furnace in Michigan.

We tend to camp in places without electricity. My hope is that the 100w solar panel will keep my battery charged to an acceptable level. I have a generator that I bring but I have a desire to not use it if possible.

The topic title is about a Furrion 12v fridge battery power usage, not 2-way Norcold fridge.

[pmsherman]

Originally Posted by Flybob

I am a little skeptical of the factory's math. On two fully charged 120amp hour 6volt batteries wired in series it will run for five days based on that same 70 degree ambient temperature.

Drawing the batteries down to 30% gives you 84 AHr or roughly 17AHrs per day ( for a 5 day trip) Assuming the fridge runs 15% of the time. It implies that it only draws 4.7A. Factory spec says Input power rating: ≤ 15A (11A @ 12V DC)
Your mileage may vary.

I believe that the reply had a typo in it - the battery capacity was written as 120AH when it should have been 220AH. The four days use at 50AH/day would then make sense.


Phil

[Hclarkx]

I don't think the Furion response helps much. Assuming the fridge draws 11 amps when running and runs a 50% duty cycle, it needs about 130 AH over 24 hours. I'm in the process of installing a 12V compressor fridge and from the research I've done, 50% duty cycle would be very good even at 70F ambient. Folks seeing a 50% duty cycle have done superb jobs of adding polyiso insulation around the fridge.

Now assume half of the 130 AH is needed during the 8 hour day when ambient is higher and half over the night 16 hours when ambient is lower. Also assume 200W of solar on a fair shoulder season day will produce about 1000 WH or about 77 AH. It will produce substantially more mid-summer and substantially less mid-winter.

Roughly then, the solar should produce a bit more than the fridge will consume and provide (net over 8 hours) just a bit of battery charging. And discount that for battery turn-around losses and there's maybe 9 or 10 AH of net charge.

Overnight the fridge will use about 65 AH for a net use of battery capacity of about 55 AH. Assuming the battery is up around 110 AH usable (50% of rating), the battery will last about two days. Less at 60% duty cycle. Less yet if it's not a good solar day and the battery gets no charge or worse, some of the fridge AH must come from the battery during the day hours.

Solar production is more than twice in mid summer what it is in mid winter. This spread is reduced if the panels are optimally adjusted every hour as might be the case here with portable panels.

Bottom line is, IMHO, one might get three days in mid summer and likely less than two days in mid-winter. And maybe one day during inclement weather in winter. And all of this assumes the fridge is the only battery user.

BTW, I have a spreadsheet that addresses this very issue. It uses solar data from the National Renewable Energy Lab in Denver for specific locations across the US. One can enter fridge, A/C, and other load data and battery and solar size and see day by day the battery SOC. It's written assuming LFP battery (near zero charge/discharge losses) but one can fudge those losses by assuming a high solar controller loss or higher than actual AH load. PM me if you'd like a copy. The solar data for a typical season is currently for the California central coast. I can explain how to download and paste in data for other locations. I suggest this spreadsheet will be useful only to those with some spreadsheet experience. PM me with your email address if you'd like files (one to crunch the NREL data and one for the analysis).

[Flybob]

Originally Posted by pmsherman

I believe that the reply had a typo in it - the battery capacity was written as 120AH when it should have been 220AH. The four days use at 50AH/day would then make sense.


Phil

I was quoting the factory example of 120AHr and questioning their math.

[SantaFe big sky]

I am waiting on delivery, I have a factory drop date of 8/20 so until then I can’t test anything. I plan to throw a meter on the circuit for an extended period while I track the coach temperatures and see what it really uses. The weak link in all of the guesses we make is what the real duty cycle will look like in real world conditions.

From that point I can start sizing my battery bank and how to keep it topped off. Calculating solar needs is a whole subject to itself. And since we all live and camp in different places everyone will have a different answer. I live in New Mexico and we just happen to have the highest solar production in the US thanks to days of sunshine, southern location and altitude.

[Hclarkx]

Originally Posted by SantaFe big sky

I am waiting on delivery, I have a factory drop date of 8/20 so until then I can’t test anything. I plan to throw a meter on the circuit for an extended period while I track the coach temperatures and see what it really uses. The weak link in all of the guesses we make is what the real duty cycle will look like in real world conditions.

From that point I can start sizing my battery bank and how to keep it topped off. Calculating solar needs is a whole subject to itself. And since we all live and camp in different places everyone will have a different answer. I live in New Mexico and we just happen to have the highest solar production in the US thanks to days of sunshine, southern location and altitude.

That's what the speadsheet does. You put in data for the location(s) you will visit and look at the months you will visit and design for them. Compare more battery vs more solar, etc. Set the combination for whatever number of generator run events you will tolerate and choose more battery or more solar based on cost and roof space available.

In my situation the spreadsheet matched my experience with my current system very well. In looking at upgrades for a 12V fridge (Nova Kool RFU8320) I found I have enough battery but need 300 Watts more (roof mounted) solar. I have 100W excess currently, so the fridge needs 400W. This is to fully eliminate generator run events in November and March when I'm generally on the central coast. With this upgrade I'm fine for January-February in AZ and NM and most other places and times.

I used conservative fridge duty cycles (different for day and night and summer and winter) based on several threads on 12V fridge AH needs here and on two other boards. Some marine articles also helped.

The only thing not implemented is recognizing that fridge use will be lower during winter inclement weather when solar is weak. This would make the results conservative, but it appears that the space heater fan will offset the reduced generator run time during inclement weather.

[SantaFe big sky]

Hclarkx that would be a very useful tool!

[JSP]

I would use the spreadsheet. Was very skeptical of 12v only when buying but I figured I spend 2 weeks a year dry camping with 100w solar and 5 hours of generator a day.. I can limp through it. Maybe not.

[Ditch_doc]

I was blindly told with a single deep cycle and 50w power pack, 55 hours. That is without doing the math. So I figure a day and a half with what I have.

[babock]

Originally Posted by Ditch_doc

I was blindly told with a single deep cycle and 50w power pack, 55 hours. That is without doing the math. So I figure a day and a half with what I have.

Too bad people get lied to and make them think a 50W or even a 100W solar panel is enough.

[Ditch_doc]

Originally Posted by babock

Too bad people get lied to and make them think a 50W or even a 100W solar panel is enough.

Oh believe me, I know they were full of it. I don’t know a lot about solar, but I do know that 50w won’t get ya far. Even if it is “high efficiency” haha

[babock]

Originally Posted by Ditch_doc

Oh believe me, I know they were full of it. I don’t know a lot about solar, but I do know that 50w won’t get ya far. Even if it is “high efficiency” haha

And if you have a PWM controller(more than likely), you are likely only getting 70% of that and that is with it perfectly aimed. Flat mounted maybe half of that 70%.