Battery for Dometic CFX3?

fd6axc4

New member
I'm just starting to look into some sort of system for my trailer. I'm looking for something lightweight, something that will power a fridge (like a Dometic CFX3 45), the ability to add a few LED lights and probably a usb outlet to charge a device. I also want the ability to add a solar panel to it to charge it up. My plan is to be off-grid for maybe 3 or 4 days tops as well. My vehicle does not have a way to charge anything, but it's something I'm thinking about in the future. I also will mostly be around the midwest, where the summer temperatures will be up to about 100* f max, but average, I would say, is about 80*.

I thought about the PLB40, which would be an easy solution but is expensive for what you get. Same with the Jackery and other solutions like that. I'm pretty handy and know how to solder and properly hook things up like that as well.

I was thinking about getting a Renogy 12v 100Ah Lithium Iron Phosphate w/ Bluetooth ( RBT100LFP12-BT-US). I figured if the PLB40 can get 40 hours of cooling on a Dometic fridge, then 100Ah would be able to do that plus a few LED's. After that, maybe look at adding a solar panel to extend the battery.

Before doing anything though, I was wondering if anybody had any comments on this setup. Thanks!
 

fd6axc4

New member
That Renogy battery is over twice the capacity of a PLB40 and about 30% less money.
Of course Renogy is not plug-n-play, but I say its a far better deal.
That's what I was thinking. Granted you would need a few cables to wire everything up. Automobile electronics isn't new to me and I know my way around a soldering iron. I wanted to check somewhere to see if I'm on the right path or if it's not going to work. I figured I could have something that might work for about 600 bucks and build out, or spend almost $900 for something that would for sure work and be limited to what I can do.
 
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67cj5

Man On a Mission
I'm just starting to look into some sort of system for my trailer. I'm looking for something lightweight, something that will power a fridge (like a Dometic CFX3 45), the ability to add a few LED lights and probably a usb outlet to charge a device. I also want the ability to add a solar panel to it to charge it up. My plan is to be off-grid for maybe 3 or 4 days tops as well. My vehicle does not have a way to charge anything, but it's something I'm thinking about in the future. I also will mostly be around the midwest, where the summer temperatures will be up to about 100* f max, but average, I would say, is about 80*.

I thought about the PLB40, which would be an easy solution but is expensive for what you get. Same with the Jackery and other solutions like that. I'm pretty handy and know how to solder and properly hook things up like that as well.

I was thinking about getting a Renogy 12v 100Ah Lithium Iron Phosphate w/ Bluetooth ( RBT100LFP12-BT-US). I figured if the PLB40 can get 40 hours of cooling on a Dometic fridge, then 100Ah would be able to do that plus a few LED's. After that, maybe look at adding a solar panel to extend the battery.

Before doing anything though, I was wondering if anybody had any comments on this setup. Thanks!
You need to forget about the Dometic CFX3 Aeries all together, they a design fault where you should be able to plug in both the AC and the DC leads at the same time and if the Grid goes down then the fridge was meant to switch its self over to DC and then switch its self back to AC Once the Grid was back on line, Ranther than fix the Issue or ReCall all the Defective CFX3 fridges Dometic's quick fix was to tell everyone not to plug in both leads which defeats the purpose of it,

Dometic are the Only fridge on the market that can't be hooked up where both leads are plugged in at the same time unless it is a 12/24v Only Models which only have one lead in the first place, So just Avoid the CFX3 like the Plague.

As for the Dometic PLB 40 they are brilliant I own 2 of them and Using just one of them I can go away for weeks at a time and if you only need 12v and USB they are about the best there is, You can forget about fitting a second battery system because they tie you to the vehicle where as the PLB can be used anywhere on earth even in your house during a powerout or Off Grid use in a Cabin or Tent etc.
 

fd6axc4

New member
You need to forget about the Dometic CFX3 Aeries all together, they a design fault where you should be able to plug in both the AC and the DC leads at the same time and if the Grid goes down then the fridge was meant to switch its self over to DC and then switch its self back to AC Once the Grid was back on line, Ranther than fix the Issue or ReCall all the Defective CFX3 fridges Dometic's quick fix was to tell everyone not to plug in both leads which defeats the purpose of it,

Dometic are the Only fridge on the market that can't be hooked up where both leads are plugged in at the same time unless it is a 12/24v Only Models which only have one lead in the first place, So just Avoid the CFX3 like the Plague.

As for the Dometic PLB 40 they are brilliant I own 2 of them and Using just one of them I can go away for weeks at a time and if you only need 12v and USB they are about the best there is, You can forget about fitting a second battery system because they tie you to the vehicle where as the PLB can be used anywhere on earth even in your house during a powerout or Off Grid use in a Cabin or Tent etc.
I did read about the issue with the CFX3 and power.

What would an alternative be that you would recommend?
 

67cj5

Man On a Mission
I did read about the issue with the CFX3 and power.

What would an alternative be that you would recommend?
If you want a single Bin version then look at the ARB Classic II series, Or if you must have a Twin setup then take a look at the ARB ZERO series, Or if price is not an Issue then take a look at the National Luna range and In 3rd place I would go for one of the Engels and in 4th place I would go with the SnoMasters, Noting that all of these 4 Brands have a perfectly Running UP's system in them where you can plug in Both Power leads at the same time and then I would choose any of the cheap Amazon fridges over the CFX3 series,

hope that helps.
 

Mashurst

Adventurer
Dometic are the Only fridge on the market that can't be hooked up where both leads are plugged in at the same time
I'm missing something here. I have a Dometic CFX3-75DZ that I use in my truck. I keep it on most of the time and plug it into shore power when parked at home. Both leads are in all the time and the DC is connected all the time. If it has AC it runs on that and does not deplete the battery. If the AC is disconnected from the truck it starts using DC.

On DC I currently run it with a small (Maybe 30Ah) AGM charged with a simple Renogy 20A DC to DC Charger. I came to this thread because I'm looking at upgrading the old AGM to a CHINS LiFePO4 50Ah or something like it. I plan to be on the move each day so I really only need it to hold up the fridge so like 18 hours or so maximum. I expect this setup will do more like a day and a half or better under most conditions.
 

67cj5

Man On a Mission
I'm missing something here. I have a Dometic CFX3-75DZ that I use in my truck. I keep it on most of the time and plug it into shore power when parked at home. Both leads are in all the time and the DC is connected all the time. If it has AC it runs on that and does not deplete the battery. If the AC is disconnected from the truck it starts using DC.

On DC I currently run it with a small (Maybe 30Ah) AGM charged with a simple Renogy 20A DC to DC Charger. I came to this thread because I'm looking at upgrading the old AGM to a CHINS LiFePO4 50Ah or something like it. I plan to be on the move each day so I really only need it to hold up the fridge so like 18 hours or so maximum. I expect this setup will do more like a day and a half or better under most conditions.
Yes you are, Your Fridge was designed to Run with both leads connected incase of a power failure when used at home or emergancy situations Or when living off grid., The trouble is when you do plug in both leads it Kills the Fridge,

As for your 30Ah Battery that can only work you are driving all day til dark and camp for the night and and drive all day the next day and repeat, repeat, In reality with your little 30Ah Battery you can only use 15Ah which is down to 50% of it's power Use any more than that and you will start doing damage to the Battery, So it was never big enough in the first place

When used in winter on Fridge mode your fridge will chew about 10 to 15Ah The moment you switch one side to a freezer your going to see the power draw go up to15 to 20Ah, Do that in Summer and it is going to Chew between 30 to 45Ah,

If a person is going to run a fridge then for the safety factor for the Battery and the Food then you need to at leased run a battery 2 and a half time bigger than what the fridge can use in 24 hours, So using the Above figures In Summer if your fridge can use 37Ah in 24 hours then the Battery should be around 93.75 Ah ( 90 to 100Ah ) Again because you should only use 50% of it's power,

If you are going to use Lithium Thats fine but a 50Ah will work but you will have nothing in reserve, You need to go up to a 60 or even better an 80Ah battery which is equal to 1024Wh, I use small 500+Wh pack in winter and I carry a spare just incase,, I also have much Larger ones if I am going to be parked up some place for a while or if I am using the Fridge as a Freezer because using it at a freezer can triple the power draw even more so in Summer, Running your fridge On Lithium I would be thinking of around 80Ah If it was a Single BIn then I would be looking at a bare minimum of 60Ah,

Hope that helps, good luck and have fun. (y)
 
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fd6axc4

New member
I'm missing something here. I have a Dometic CFX3-75DZ that I use in my truck. I keep it on most of the time and plug it into shore power when parked at home. Both leads are in all the time and the DC is connected all the time. If it has AC it runs on that and does not deplete the battery. If the AC is disconnected from the truck it starts using DC.

On DC I currently run it with a small (Maybe 30Ah) AGM charged with a simple Renogy 20A DC to DC Charger. I came to this thread because I'm looking at upgrading the old AGM to a CHINS LiFePO4 50Ah or something like it. I plan to be on the move each day so I really only need it to hold up the fridge so like 18 hours or so maximum. I expect this setup will do more like a day and a half or better under most conditions.
Here's a recall notice about it:


I'm focused on the cfx3 45 model, and models that are in that 40-some and low 50-some range. I don't need a freezer; just want a fridge (well, single bin).

Because of the charge recall issue and only resolution is a sticker that says not do it, and also because of the 'warning 33' error, I'm starting to look elsewhere. The ARB Zero line is what I'm looking at now. I like the Zero vs the Classic because it has an ac port on the front and says it can be used with a portable power pack. On the other hand, the classic advertises the 'secop compressor' whereas I have no clue what's in the zero. As you can see, I'm more nitpicking about features and want something more reliable.

I also have to double check the dimensions. Now that I look at it, I think my drawer only has enough room for 16" wide. The Zero is 16.7". So that may be my deciding factor on getting the Classic.
 

Mashurst

Adventurer
Here's a recall notice about it:

Thanks for the info. This is what I was missing. I'll have to reach out to domestic and see about my unit. Since I don't have anything else on the circuit with my fridge other than the battery itself, I may not have noticed the problem, though I suspect my unit simply has not experienced the failure. It sounds like domestic is willing to take the units back. Thanks for bringing this to my attention.

The information on my battery was meant for you as a point of reference when thinking about your system. The small AGM does hold up the large fridge overnight just fine, even if we set camp mid-afternoon, as long as it gets a good charge during the day. As 67cj5 noted, it only works if we are moving during the day. Since that is precisely how we use the vehicle, it works ok for us. Weight is a constant limitation for my setup, so while it would be luxurious to have, say 200Ah of lithium, for me, it is not a good use of weight budget. I think moving to the 50Ah lithium will give us a considerable margin, especially since the charge time will be much faster as well, and it should actually weigh marginally less.
 

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