Dometic Cff35

Just packing for our first long trip; 2 weeks. Wondering if and how others use there fridge? We are wanting to pack fridge / freezer goods and keep for the duration or while we consume. Do I use the 12VDC or 120VAC also have that cigarette do daddy lol. Haven't downloaded the manual yet so apologize for the quick question.

On another note we have the solar option and curious how much this may drain the system. I am just trying to get a good gauge on how to properly use everything. Unless it's 30*F at night my wife will have the fan running regardless.

 

Best to use the 120V outlet if you have electric hookups at your campsites, that allows your battery to get fully charged at camp, and not be constantly draining using the 12 V outlet, and less demand on the charger as well. If you don't have electric hookup and are just using solar to keep the CI battery charged, the fridge/freezer can deplete the battery over night depending on what size battery you have, and outside temps.

That's one of the reasons we added a sogen to our equip list, which easily keeps the fridge going overnight using the 12V outlet on the sogen, without using the CI battery.

If you don't have a sogen for the fridge, I found that it is insulated well enough that even if unplugged, it will keep it's temp fairly well ( go up just a few degrees) overnight if it's already loaded with cold food, and kept closed. Then plug it back in as soon as the solar is charging again. That's my experience, YMMV. Have a great road trip!

 

You’ll find a number of variations on the use of the Dometic among CI folk. We have mostly settled on running the fridge in freezer mode with a dozen or so spring water bottles and any frozen foods and then switching those frozen bottles out with other bottles in a good cooler, hence never buy ice. Dometic as ice machine. Running the unit in the TV while traveling goes easy on the CI battery. If you do have shore power that is the best source for the Dometic. Just plug into 110 on the CI. If you don’t have shore power use 12V and your solar. Of course solar can be iffy, just keep an eye on the volt/amp meter in the CI. You’ll note in the manual that the Dometic has a battery mgt function you can set to avoid killing your car battery or the CI supply battery. FYI… if the source batt gets below the voltage threshold you've set on the Dometic it will shut down and not crank back up until it’s reading is at least back to the “restart voltage level” . Took some experimentation for us + CI cust service. We also tend to do a lot of camping without shore power. Feel free to direct message me for further discussion. Also, I’ve found Dometic cust support line to be excellent.

 

Bob, thanks. This is how I use mine, too.
Powered by a sogen in dispersed camping, that is in turn recharged by solar.

In high ambient temps (>90f) the CF35 running in freezer mode will drain a Group24 like the CI lead acid battery in 4-6 hrs, 6-8 if similar sized lion.

And the cigarette lighter dC plug is a bit fragile, so I have to be sure to strap sogen and cf35 down in TV so the cig lighter plug doesnt get jammed and bust off the tip which houses the fuse.

I use the silver Coleman cooler that CI sells for veggies, stored in galley whilr traveling or away from camp.
This is kept cool by rotating in frozen water bottles and/or Yeti blocks once a day, from the CF in freezer mode. No soggy food or trips to the store after 2-3 days for ice.

I store hard frozen meat/ice cream in the CF35 and notice it takes a day to hard freeze the water bottles best laid flat at bottom or next to the raised side, which is coldest. Its a bit of juggling twice a day, so I try to keep it closed otherwise.

Next upgrade will be a YETI in galley as veggie cooler; as its much better insulated than the Coleman.

 

Thanks for all the comments and direction thus far! Really trying to figure what's best for our travel purposes and we haven't begun to figure that out yet. Lots of excitement to come. BobF never thought about reaching out to the Dometic team and should have thought of that. I just reached out to the Bundutec USA and I could not have asked for better support. Jenna(?) posted a you tube video after yesterday after I inquired about the purposes of the stakes that came with the awning that afternoon.

 

Something else just to clarify a few things. "TV" = travel vehicle?
While towing/traveling my vehicle will power the CF35?
Our 560 does have the AGM batteries

 

I have the same fridge, and it works very well. I run my exclusively from 12 volts, though I keep the temperature set closer to the mid-30s (below 40). My onboard battery is an 86Ah AGM, so I can be 'dry' for 2 days before I am looking for power. That, for me, 99 times out of 100 will be from a camp site power pole (meaning I never need to as I plug in immediately) If you are freezing, it will use more power.

The reason I run exclusively from 12 volt is that the power poles at almost every campground are unpredictable --- most campgrounds were built it he 1950 and 60s (we stay exclusively at state parks) and are not sized to have "full" weekends with RV's with Air Conditioning, Microwaves, Hair Dryers, water heaters, air fryers etc. They were sized mostly for a few lights, and perhaps a fan or two. They have been retrofitted, but most of those retrofits were for a 30 amp rig, that might have a single AC. Now, I'll see 2 AC's routinely, and I've even started to see 3 ACs. Or, I'll see a Tesla plugged in instead of an RV, which pull the full capacity of the pole for the whole charging cycle of the vehicle.

This all means that the voltage at the pole can drop down significantly, and can even start to damage sensitive electronics. My domestic is the single most expensive accessory I have, I want to keep it isolated from "120" volts.

On really hot days 3 things will matter the most to the CFF:

1 -- Keep it out of direct sun
2 -- Keep the airflow, the fridge needs to breathe.
3 -- When traveling on hot days, its a good idea t put the fridge inside the tow vehicle, using a colman style ice chest to hold the stove in place in the galley.

I love my CFF35 --- I would suggest buying a replacement thermistor before you need it. There's a couple threads in this forum where replacing that part has been discussed. I can tell you when I got mine SUMMIT racing sells them for the ARB, they also work on the Dometics.

I have found this to be the single most failure-prone component in the fridge. I have a CFF35 and an ARB fridge (both are based on similar Danfoss compressors/controllers) --- So far, I've replaced both thermistors once. I replaced the thermistor in my previously owned CF35 twice. Its super easy and just needs a screwdriver to do...but it sucks when you're out and suddenly your freezer/fridge is 50 degrees, or, its running continuously and is totally iced up, which can damage the compressor --- which is why I have a CFF35 now instead of a CF35.

Invest in a good in-fridge thermometer. Mine is electronic and has "min/max/current" temperatures. These small fridges do have temperature swings that are larger than a large home chest.

IF you charge with a solar panel, have 200 watts and on a sunny day, my house battery is full in a few hours (2-4) and I'm a power hog. I have yet to fully quantify that -- Just enough to say it works well.

 

Great explanation, Sweeney, and the tip on replacement thermistors. This is a good example of symptoms and how-to:
Dometic Cff35 - Bad Thermistor?

Self: get a spare now and stash it with other spares.

Ya, I'm always wary of campground power esp when its pouring and finding corroded and busted fittings in older campgrounds on posts sitting in puddles...

Am I correct in understanding that while on DC, via the CI battery, that the Dometic is essentially getting power that's 'buffered' out by being less subject to damage by voltage, reversed polarity, and amperage variations on the campground stand?

Then the only item getting wear and tear is the shore charger thats in the CI?

 

I've got 3 The last came from Summit Racing. I can look up the part number if you need it. Theirs was the best price, especially so when you factor in shipping...The RV places rook ya.

As for voltage, correct -- I just use the 12 volt system as a buffer to isolate it from the 120 volt. I've been at camp sites in the summer where voltages dropped well below 110. My old big-rig sensed voltage, and what power I was using compared to what I had available (30 amp / 50 amp) and would strategically turn things off to keep me safe. If the line voltage dropped, it cut the whole system out. I'm sure this saved my ACs. And more than once I had to start the generator to keep things cool. Those days suck. If I were in the CI, my AC woulnt' run --- but at least my fridge, fans, and lights were working.

Campgrounds are notoriously badly wired. I've seen carbon scoring dozens of times on the 30 amp outlets at the power pole. The 110's are usually better. But its not uncommon to find floating grounds and reverse polarity there. I always plug in a circuit tester before I plug in Serenity, and test the GFCI...again, its amazing how often they don't work. At leat 50% of the time...

If I get bad AC, the worst case scenario is cooking the charger and the Air Conditioner --- everything else I have, is from the 12 volt battery.

 

I second Dustin and Sweeney's tips: running it solely off 12V, either via a sogen portable lithium, or the trailer battery (but not necessarily at the same time you are charging the trailer battery from shore power.) The fridge is generally the biggest amp draw out of most of the 12V appliances, and can pull up to 7A under some circumstances. Best not to be trying to charge a deeply depleted battery on shore power at the same time you are running the fridge, as Dustin cautions. You don't have much choice with the pump, fan and lights. But those are generally much lower or shorter Amp draws.

I use a Progressive Industries surge protector at the post, as my AC source, after it tells me it has passed all the potential dirty voltage, crossed-wires tests that Sweeney accurately describes. But I still won't plug the Dometic into it.

On the road, the Dometic usually travels in the back of the TV. Especially in warmer weather. If I know that the TV alternator will be working double-duty charging a depleted trailer battery (because we didn't have a power site the night before) then I''ll let the sogen power the Dometic while in the TV as well, rather than further tax the TV alternator.

 

Yours pulling 7 amps? I only see ~3 amps and it is in short bursts....just a few minutes at a time. If you keep it colder, the amperage shouldn't change but the duration it runs will increase. I THINK the compressor is variable -- need to throw a high mass item into the chest that is warm to see.

The fridge can cool off warm things, but it is not where near as fast as a home freezer/fridge...its best if our food is prefrozen/cold.

Ditto on what else you said....

 

I haven't put a meter on it recently. If memory serves, I think I've seen it s high as 5.0A at some point. I was going by the spec sheet/label on mine. Which I did think was a little high. But possible, I suppose.

Cut and paste from a CF35 page:

• Rated input current (DC) 7 A
• Energy Consumption 12VDC (Ambient@90F, Internal@41F) 0.85 Ah/h

 

I haven't seen mine to that far, but frankly, even if it does it is the duty cycle that will matter most....