Voltage Drop Dometic CFX 75DZW

[karmabiker]

Ignore what the fridge says. Check the voltage at the battery terminals and in the end of the dometic plug that plugs into the fridge (Plug the VOM into the power wire directly.). That will tell you if you have a wiring issue or if it's the internals of the fridge. Based on my experience with dometic I would venture that there isn't significant drop in your wiring. FYI the CF-80 in my sig line was replaced under warranty by a CFX-75DZW, I've chased this rabbit...

 

[MtnBubba]

I just did a maiden voyage with my CFX50 and was getting faulty compressor warnings on the app. I also got voltage drops over 2V at times using the app. Other times the voltage drop was negligible. I don’t think the Dometic is measuring voltage at the connector.

I was seeing 10.1 volts on the app at times where the battery voltage was 12.5-14.5.

I just went out and checked the voltage drop from the battery terminals to the 12v plug in the back of my vehicle (2002 Tahoe) using the Dometic 12v wire, measured at the end of the Dometic plug. Voltage drop was 0.03 volts engine off. 0.06 volts engine and alternator on.

Using this 12v plug, and starting at 80 deg F, it took 36 hours to cool a brand new CFX50 to 37 deg. 20 of those hours were with the engine running and voltage at the plug over 14v. At the 24 hr point, I though is was a battery that was in need of replacement and bought a new battery. It still took another 10 hrs to get down to 37 deg. With the engine off and battery voltage between 12.5 and 12.9, I could hear the CDX50 compressor “try” to start and it never got going. When I tested it in the house using AC power, it took less than an hour. to cool it to 37.

I tried it on a dedicated battery, basically wired direct. At the battery I was seeing 12.35, and on the app 10.9v with the compressor running.

I’m wondering if the vehicle 12v plug won’t supply the dc current required? It’s not blowing a fuse... but my CFX50 takes about 57W to run on DC.

 

[Voodoo Blue 57]

I've use a straight pin to push through the insulation to measure voltage. You are not destroying the wire or compromising the wires integrity if done right. You want to push the pin in just enough to contact the center conductor. Because the hole is small the insulation will self heal but if you are concerned with a small hole in the insulation you can but some black tape over it when you are finished.

 

[MtnBubba]

If you already know that the voltage drop along the 12v Dometic wire is zero, then you don’t need to do a destructive test to measure the voltage at the fridge.

If you still need to know these voltages, make a cigarette plug extension that you can tap into with test leads. It doesn’t have to be long enough to have a voltage drop itself. Measure the voltage without the fridge, and then plugged in, and so on.

Or if it’s not too hard, remove the receptacle you are using and measure the voltage in each situation from the back of the receptacle.

 

[luthj]

There are needle probes which use the standard multimeter test lead connectors. It should be a simple matter to isolate where the voltage drop is occurring. Then remedy the issue.

 

[MtnBubba]

I think the voltage drop is internal. I have my CFX50 wired directly to a stand-alone battery and the app reads 10.9, when the battery is 12.35 with my Fluke. There is negligible drop along the 12V supplied Dometic power wire.

 

[luthj]

It could be a loose connection or bad crimp inside the unit. It could also be a bad connection at the external connector. Depending on your warranty status, you can return, or you can remove the external cover to trace down the issue internally.

 

[solspot]

i have the same issue on my cfx-50: 1.1 - 1.2 voltage drop internal reading. Did you determine the root cause?

 

[67cj5]

For some reason nearly all fridges register a voltage drop, My Fluke tells me I have 12.9+v when the fridge is running yet the Snomaster will say something like 11.7v while running, yet when I check one of my ARB's I measured the voltage drop between 0.15 and 0.20v at the most.

The only voltage that matters is the voltage that is coming out of the plug that you plug in to the fridge, For some reason the voltage that some fridges display has nothing to do with real whole voltage,

This is where too many bells and whistles on a fridge is a bad thing and Apps just make it worse, why on earth does a fridge need Bluetooth god only knows, and It is totally stupid because all it does is make people worry about something beyond their control, For 120 years we have managed to survive without built in volt meters and Bluetooth on our fridges, And NO it is not useful and NO you don't need it, that's just BS, It takes longer to get the app to come up on the screen and scroll through the menu than it does to get up off ya ass and go and see what the fridge is doing,

Then there is all the trouble most of you have had with getting the app to run, The best fridges on the market are the Dometic CDF-18 and, Engels without the LED readout, Why you may ask ?? well just look as see how many threads there are hear of people moaning that their fridge temp does not match what is on the LED Display, And LED displays and Bluetooth is just more to go wrong and the new CFX3 range is a prime example of that.

The Dometic CDF-18 and some of the Engels without the LED display are some of the most reliable fridges on the market which is why some of them are still running after 40 years of abuse, and the Blue and Grey series ARB's are about as high tech as a person should buy if you plan on taking a fridge out in the bush,

 

[solspot]

For some reason nearly all fridges register a voltage drop, My Fluke tells me I have 12.9+v when the fridge is running yet the Snomaster will say something like 11.7v while running, yet when I check one of my ARB's I measured the voltage drop between 0.15 and 0.20v at the most.

The only voltage that matters is the voltage that is coming out of the plug that you plug in to the fridge, For some reason the voltage that some fridges display has nothing to do with real whole voltage,

This is where too many bells and whistles on a fridge is a bad thing and Apps just make it worse, why on earth does a fridge need Bluetooth god only knows, and It is totally stupid because all it does is make people worry about something beyond their control, For 120 years we have managed to survive without built in volt meters and Bluetooth on our fridges, And NO it is not useful and NO you don't need it, that's just BS, It takes longer to get the app to come up on the screen and scroll through the menu than it does to get up off ya ass and go and see what the fridge is doing,

Then there is all the trouble most of you have had with getting the app to run, The best fridges on the market are the Dometic CDF-18 and, Engels without the LED readout, Why you may ask ?? well just look as see how many threads there are hear of people moaning that their fridge temp does not match what is on the LED Display, And LED displays and Bluetooth is just more to go wrong and the new CFX3 range is a prime example of that.

The Dometic CDF-18 and some of the Engels without the LED display are some of the most reliable fridges on the market which is why some of them are still running after 40 years of abuse, and the Blue and Grey series ARB's are about as high tech as a person should buy if you plan on taking a fridge out in the bush,

Agreed on the too many bells and whistles causing other problems.
Unfortunately the voltage reading causes the battery protection to kick in: Which renders the Hi (11.8v) unusable and Medium (11.2) quickly behind with a 1.2 voltage drop reading. So i have had to use the low (10.1v) setting for any usage. Hopefully @Dometic will respond with some answers.

 

[67cj5]

Agreed on the too many bells and whistles causing other problems.
Unfortunately the voltage reading causes the battery protection to kick in: Which renders the Hi (11.8v) unusable and Medium (11.2) quickly behind with a 1.2 voltage drop reading. So i have had to use the low (10.1v) setting for any usage. Hopefully @Dometic will respond with some answers.

Yeah, you hit the nail on the head there, Because you will have the same issue with the voltage cut off when you run some of their DC 12v/24v volt fridges from an AC to DC adapter, left on Hi I had problems with the fridge shutting down, when I switched the voltage protector to Low the fridge ran perfectly, The ARB's ran fine at either setting, The Snomasters ate my batteries so fast but when the fridge is running the built in volt meter reads way too low and the only time they read correct is when they have stopped running,

I would rather a fridge did not have a volt meter because it is impossible to track the voltage and when I hooked up the fluke direct to the battery I got the correct reading but I am not going hard wire a 600$$ meter to the Van, The displayed voltage drop is impossible to ignore because it caused me to set the fridge cut out to Low just in case I had an issue, where the voltage became my concern and not the journey,

Bottom line is the Wilderness or Off Road driving is not where a person needs to be facing such an issue and the fridge voltage "must" display the correct info 24/7 and if they can't get them to read correctly then they need to remove that feature from the fridge because if this problem I would rather have one of the Dometic CDF-18's or the early Engel's with the rotary dials and people need to ignore the BS info that Snomaster dealers are claiming because their fridges will eat batteries by the dozen,

 

[Dometic]

Agreed on the too many bells and whistles causing other problems.
Unfortunately the voltage reading causes the battery protection to kick in: Which renders the Hi (11.8v) unusable and Medium (11.2) quickly behind with a 1.2 voltage drop reading. So i have had to use the low (10.1v) setting for any usage. Hopefully @Dometic will respond with some answers.

Can you tell us if you are using OEM wiring and a power outlet to power your cooler or a do you have a direct wire/fused connection directly to your battery?

DOMETIC
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shop.dometic.com
Use promo code Expedition20 for $25 off your order of $75+

 

[solspot]

Can you tell us if you are using OEM wiring and a power outlet to power your cooler or a do you have a direct wire/fused connection directly to your battery?

DOMETIC
mobile living made easy
shop.dometic.com
Use promo code Expedition20 for $25 off your order of $75+

In my vehicle the wiring is custom 1/0 gauge wiring dual battery setup via Blue Sea Components (nominal voltage loss over 20 foot run). The issue is not the wiring but seems to be internal to the refrigerator.

I have run the following test outside of the vehicle:
Refrigerator directly connected to a battery (with Dometic DC cord connected to battery via alligator clip cable )

Under load (refrigerator running) I get the following readings:
Battery (voltage meter): 12.12v


Refrigerator (via app):10.5v

No Load:
Battery (voltage meter): 12.36V
Dometic DC cable (voltage meter prongs into end of cable):12.33V
*Nominal voltage drop from the cable

 

[Milarepa]

I love such classic situations ... They ask you what cable you are using, even though they know that the problem lies in their device. I have exactly the same symptoms with my CFX75. The reading on the battery is 11.5V, the reading on the loaded refrigerator is 9.5V and the copressor is turned off. Everything works fine on AC ... We need answers what's f*cked up and what needs to be replaced. It would seem simple ...

 

[67cj5]

Dometic knew there was a problem with the CFX3 range of fridges from the very Start and instead of fixing the issue so both leads can be plugged in at the same time like every other fridge their way around it was to tell people not to plug in both leads at the same time, Instead of recalling the CFX3 models.

Ever since above mentioned problem nearly every person who has bought one of the CFX3 range the prolems keep mounting up and all the owners need to get together and confront Dometic as a whole, This is beyond a joke now, Sadly a lot of people were warned but they still kept the faith with the sales pitch Dometic were telling folks and after 2 years Dometic have not done a thing apart from hand out quite a few refunds, If anyone can't get these issues resolved then ask for a refund and buy another Proven brand,

Sorry Guy's It's not what you want to here but the CFX3 is One Rash that will not go away.