DC Fridge or AC fridge with inverter?

[OnTheRoadAgain]

I am not arguing about anything, I am just pointing out what inverter will draw even when there is no load connected. I use inverters myself.
The 1A draw do added to the tatal power draw.
BTW, did you actually using current meter to verify the current draw instead of using Jackery as the measuring device?

I'll do some more tests and circle back on that.

I'll use a little more energy for my AC fridge, but it fills the bill nicely for me for now.

 

[Luthj]

There has been a lot discussed about using 120V fridges on the full time vehicle dweller forums. Here are the cliff notes.

• Avoid units with the condenser under the skin, external condenser only
• Units with mechanical thermostats can be rewired so the thermostat triggers a small pure sine inverter dedicated to the fridge. When the fridge is off, the inverter is off.
• many dorm units have crap for insulation. They will eat twice the energy as well insulated units. My 110L DC fridge with good insulation uses about 450watt-hours in modest temps, and up to 650 if my van is closed up in desert summer temps.
• If possible add some foam insulation to all the exterior surfaces to improve performance. The doors especially are thin. 3" or more is desired.
• Many cheap units have small/warm freezers, so take that into account.

 

[Bud Martin]

I'll do some more tests and circle back on that.

I'll use a little more energy for my AC fridge, but it fills the bill nicely for me for now.

BTW, I am a llittle confused about your setup, you have Jackery solar power generator, correct? and also Renogy 12V 1000W inverter (>80A of current from 12V source at 1000W, actually will be a lot more than 80A due to conversion loss). So how did you connect the Renogy 1000W inverter to the Jakery 500 (built-in 500W) inverter to measure the idling current draw of the Renogy? Just curious.

 

[OnTheRoadAgain]

BTW, I am a llittle confused about your setup, you have Jackery solar power generator, correct? and also Renogy 12V 1000W inverter (>80A of current from 12V source at 1000W, actually will be a lot more than 80A due to conversion loss). So how did you connect the Renogy 1000W inverter to the Jakery 500 (built-in 500W) inverter to measure the idling current draw of the Renogy? Just curious.

Will circle back after more testing.
Wanna make extra sure I'm posting accurate info.

But I did not connect the Renogy to the Jackery. Where did I say that?

 

[Bud Martin]

Will circle back after more testing.
Wanna make extra sure I'm posting accurate info.

But I did not connect the Renogy to the Jackery. Where did I say that?

Your post #39:
"I measured 3-4 watts at idle with the Jackery 500....not 12Watts", You also show the Renogy inverter spec that shows <1A fo standby current, that is how I come up with the estimate 12W of idling power. Measured with: meaning you use jackery to make the measurement, that is the way I see it
So are you saying that you do not have the Renogy Inverter since you show the spec sheet of it in your post #37.

 

[MrNatural22]

The one important thing about small AC fridges is they are made to sit motionless in a cabinet or on a countertop. Mobile use causes vibration and shocks. They WILL fail prematurely getting jostled around in a vehicle or RV. I went through two of them in three years.
They may last years on your bar or in your garage (my garages bar fridge is 5 years old and still keeping the brews cold)
Put them in a rough situation and they die.

 

[Freep]

We got it for two reasons- 1) we eliminated propane from the inside of the trailer. Why? Because. Heater is quieter than the gas one, don't have the CO/propane issues in the enclosure,

What are you doing for heat?

 

[OnTheRoadAgain]

The one important thing about small AC fridges is they are made to sit motionless in a cabinet or on a countertop. Mobile use causes vibration and shocks. They WILL fail prematurely getting jostled around in a vehicle or RV. I went through two of them in three years.
They may last years on your bar or in your garage (my garages bar fridge is 5 years old and still keeping the brews cold)
Put them in a rough situation and they die.

Danfoss DC compressors are touted as having better internal suspension allowing greater resistance or dampening of external forces.
I wonder if the less expensive DC compressors are equally rugged? I would guess not. Alpicool compressors for example are probably similar to AC compressors in their motion dampening.

These are metrics that are very subjective since actually testing this is rather difficult. Having seen the inside of these AC compressors, I have some reservations about claims of damage by mild motion. They nearly all have springs inside to "float" the compressor and rubber bushings on the outside.
You wouldn't want to go off roading with one running in the vehicle, but I don't see how mild motion such as would occur with road travel could damage them. What is more likely is the FLUID sloshing around and that fluid contains the lubricating oil. But this would occur in both AC and DC compressors.

An apparent solution might be powering off an AC compressor during travel and then powering it back up when stationary.
AC refrigerators can cool very quickly. 80F - 40F in less than an hour.

Don't know for certain but these are my thoughts. If someone has some more scientific evidence it would be interesting.

 

[alfaeric]

What are you doing for heat?

small space heater.

Right now, we are 1) not planning on going off grid, and 2) not planning on camping in that cold of weather. And we've been working in the camper with a 1500W space heater- which has been surprisingly effective when it's gotten really cold.

We also have an 1800W electric burner.

 

[alfaeric]

Danfoss DC compressors are touted as having better internal suspension allowing greater resistance or dampening of external forces.
I wonder if the less expensive DC compressors are equally rugged? I would guess not. Alpicool compressors for example are probably similar to AC compressors in their motion dampening.

It should also be noted that many of the Danfoss compressor fridges are marketed toward marine solutions- so that sail boats do not have a constant flame to keep food cold. Which is a pretty harsh environment to survive in.

 

[Zwy]

As I said, I personally wouldn't buy a compressor-type fridge for off-grid use ... though that one does come with wifi connectivity so it is kinda swinging for me!!

No, but seriously, this does kinda look cool (pun intended) and does run off both AC and DC.

And charges your f'in phone too! Right, that's me sold!

I've owned one for 2 years. Very efficient, these draw about 36 watts when it is running. When I go on a trip, I don't leave home without it.

 

[OnTheRoadAgain]

 

[OnTheRoadAgain]

Discussion is one thing......Evidence is another

Testing done with a Renogy 1000Watt Inverter and a PZEM-015 Energy Monitor with 100Amp shunt
Refrigerator is a new, Galanz 1.7 Cu Ft fridge purchased from Walmart for.........$79.00 with free shipping.

Test results include Inverter draw.


Compressor at idle....401 mA drawn by the inverter which is ON....46 minutes into test



AC Refrigerator has been running 1 hour and 8 minutes.
At the 1 hour mark the WH usage was 29Wh


Assuming power overnight will remain constant at 29WH per hour (including inverter) then 8 hours overnight the
AC fridge should only use 232 Watt Hours.

 

[Bud Martin]

Let it run for 24 Hours and show us the total Wh since the compressor will cycle on and off depend on the temperature.

The inverter in standby is using 21Wh as shown in pictures #2

"Assuming power overnight will remain constant at 2.22WH per hour (including inverter) then 8 hours overnight the
AC fridge should only use 17.76 Watt Hours. I'm wondering if DC fridges can do that good ?"
Where did you get the 2.22WH from? I do not see that on the display.
Right now the display is showing in 1 Hour and 8 minute the power consumption is 29Wh as shown in picture #3

 

[OnTheRoadAgain]

Let it run for 24 Hours and show us the total Wh since the compressor will cycle on and off depend on the temperature.

"Assuming power overnight will remain constant at 2.22WH per hour (including inverter) then 8 hours overnight the
AC fridge should only use 17.76 Watt Hours. I'm wondering if DC fridges can do that good ?"
Where did you get the 2.22WH from? I do not see that on the display.
Right now the display is showing in 1 Hour and 8 minute the power consumption is 29Wh.

I probably shouldn't be trying to do this late at night.

Right.........now I have to reconsider.......29WATT Hours x 8 hours = 232 WATT HOURS.

I'm still happy. Not sure why I got fixated on AH.

Do you know what a 65 Liter DC fridge would use on average for that same time?

 

[Bud Martin]

Please don't bust my bubble......I'm a senile......I mean senior sitizen.

Right....now I have to reconsider.......29WATT Hours x 8 hours = 232 WATT HOURS.

I'm still happy. Not sure why I got fixated on AH.

Do you know what a 65 Liter DC fridge would use on average for that same time?

I'm 67 years old.
My 20 years old or more 26 cu.ft AC fridge uses 2KWH a day so yous is 29W x 24H = 696WH (0.696KWH) a day.

 

[OnTheRoadAgain]

I'm 67 years old.
My 26 cu.ft AC fridge uses 2KWH a day.

How old is your 26cu ft fridge? Seems like a bit much.
I recall last time we had an extended power outage here I ran our kitchen fridge which I think is 23 or 24 cu ft overnight on a car battery and a cheap inverter from Harbor Freight. When I say "overnight" IIRC it was from about 11pm until.
Had to be less than 50AH available from that battery.

I'm curious now what a 65 Liter DC fridge would use.

I measured the inverter when not powering anything but ON uses about 5 Watts IIRC.
I know for sure it was 400mA

So less than half an Amp for the Inverter and around 4Amps when the compressor was running which was less than half the time.

 

[Bud Martin]

How old is your 26cu ft fridge? Seems like a bit much.
I recall last time we had an extended power outage here I ran our kitchen fridge which I think is 23 or 23 cu ft overnight on a car battery and a cheap inverter from Harbor Freight. When I say "overnight" IIRC it was from about 11pm until.
Had to be less than 50AH available from that battery.

I'm curious now what a 65 Liter DC fridge would use.

I measured the inverter when not powering anything but ON uses about 5 Watts IIRC.
I know for sure it was 400mA

So less than half an Amp for the Inverter and around 4Amps when the compressor was running which was less than half the time.

20 years old or more fridge. I built my solar system last year after having power outage for more than 4 days during the fire in No Cal. I have 12V 1000W system 280Ah & 90Ah battery packs, 3000W inverter; the system produces about 3.6KWh per day which is what I want and enough to run the firdge and computer, small lights during power outage, my stove& water heater are gas which is great so I can still cook and clean, but the main thing that I made my solar system is for the learning experience since I never look into solar even though my job was electronics design of AC power products for 25 years, so it is just another leaning for me, I never stop learning no matter how old I will get, it is fun and it keeps my brain sharp during the retirement..

 

[OnTheRoadAgain]

20 years old or more fridge.

Yeah...I was thinking that.
They aren't as efficient as they age. Kinda like me I suppose.

 

[HRTKD]

You two guys aren't going to start comparing geriatric medications, are you?

Lots of RV's are starting to get residential refrigerators in them from the factory. I haven't heard of any problems due to them being in a mobile environment. The propane/AC refrigerator in my RV isn't doing so well, especially in summer. If I could get an AC powered refrigerator to fit, that wouldn't suck up too much juice, it probably would cost less than a replacement propane/AC refrigerator.