Refridgerators and Power Use

[Taku]

Starting to gather the parts and pieces for a new camper. I am not an electrical person but I know a number of other folks in this forum are, so here is my question: How can I compare the power consumption between fridge? For example, looking at the Truckfridge TF65 that has the following"

- 40 amps @24 hours @ 75 degrees internal temp at 36 degrees

While the Dometic says this:


Energy consumption (DC@5/32°C), [kWh/24h]
0.5634432


Any interpretation would be appreciated.

One other question on the TF65 - it comes with a freezer included so I assume the power consumption would be higher than a fridge alone. Thanks.

 

[Happyjax]

I have a top loading Truckfridge...I think it's a TF49. Runs 24/7 and even when I had lights and heater on I never saw any major dip in battery power but I do have a 100ah Battleborn.... Love the fridge!

 

[TacomaAustin]

My fridge is way smaller than a 65 liter model.

Keep in mind that number of watts used per hour will vary with the ambient temperature. My 6 year old Truckfridge TB41A is a top loader. It pulls about 33 watts in ECO mode while the compressor is running, which is almost 3 amps. I usually set the temp to 35 to 36 degrees, 2° Celsius.

Over an hour this little chest fridge will average:

• at 70° Fahrenheit ~ 9 watt/hours or .7 amp hours
• at 85° F ~ 17 watts per hour - or - 1.3 Ah
• at 100°F ~ 33 watts per hour - or - 2.7 Ah

At 100° Fahrenheit, my guess is the compressor in the fridge needs to run continuously. So, in the field, at different times of day - you'll get different results.

 

[ckent323]

I did a quick search and found the following:

How much power does a 12 volt fridge use? | Vansage

this:

what does a 12volt compressor fridge really draw

and this:

 

[Jon R]

Truckfridge’s expression of energy consumption makes no sense from an electrical unit perspective. However, they state that, when it’s running, it draws 6 amps. If the duty cycle was that jt runs about 1/4 of the time that would be 36 Amp-hours per day. So I suspect they meant the average energy consumption is 40 Amp-hours per day (from a 12 vdc system).

Dometic used units that correctly indicate average energy consumption: 563 watt hours per day

For comparison between manufacturer’s energy consumption rate information, 12 watt hours per day equals roughly 1 amp hour per day.

So convert Truckfridge’s number by multiplying by 12 to get 480 watt-hours per day.

 

[bsharp007]

I think that's a fairly accurate estimate, my 85 liter Dometic fridge uses about 30-40 amp hours in a 24 hour period with temps in the 70-80 range.