TruckFridge TF51A Test Results

I did a test run with the new TruckFridge TF51A. I started at 8:00am in the morning. I wanted some mass in the fridge so I put in two gallon plastic bottles of water. The water was at around 75°, I grabbed it out of the garage. This turned out to be a bit of a workout to chill down that much water. I started with the battery at 12.86V. When running in the ECO mode the unit draws between 2.5 – 2.9 amps. (I did a test in MAX mode and the unit draws twice the amps – 5.5 to 6 amps – compared to ECO) It ran continuously from 8:00 am until 2:00 pm to reach the set temperature of 36°

5:00 pm Battery at 12.67V and used 20.3 AmpHours
8:00 am (24 hours) Battery at 12.54V and used 28.9 AmpHours
6:00 pm Battery at 12.42V and used 37.6 AmpHours
8:00 am (48 hours) Battery at 12.26V and used 44.2 AmpHours

The initial 24 hours stresses the need to pre cool the fridge and the food/drink going into it. The first 24 hours consumed 29 AmpHours and the second 24 hours used 15.2 AmpHours. The camper was open and in shade/sun throughout the day. The high both days was 86 with overnight low 60.

How did you measure the amp-hours used? With an inline meter like we discussed?

How did you measure the amp-hours used? With an inline meter like we discussed?


Affirmative Mr. BC. I used a watts up meter wired inline.

I am continuing with data collection on how this fridge runs. I made a simple cover for the unit out of reflectix.



And to clarify how I am obtaining this data, I am using a Watt's Up meter that MarkBC suggested. This is a photo of the latest reading.



The conditions are about identical to my last test on the second 24 hours. The surrounding temperatures are very close with a high of 84° and a low of 60°. The fridge is set at 36° with two one gallon plastic bottles of water. The data from the last 24 hours-

0900 13.0V 0 Ah
1125 12.86V 1.33 Ah
1440 12.92V 3.67 Ah
1712 12.91V 5.34 Ah
2008 12.79V 11.42 Ah
0900 12.76V 12.04 Ah

If I compare this to the 15.2Ah used per the second 24 hours in the first test, with the reflectix cover my Ah useage dropped by 3Ah. Interesting result I see is the minimal draw overnight between 8 pm and 9 am this morning.

Sorry, I switched to 24 hr time with the last results. Habit.

Another energy savings idea, and maybe a potential future test idea for you señor 3 pin...
...sometimes we are lazy and don't feel like moving our fridge from the backseat of the truck to the camper if we are doing a quick overnighter. Even though the ARB has a low voltage cut off I've found I can simply turn the fridge off before bed time and then turn it back on in the morning. We run ours at 29F and after leaving it off over night (usually ~9 hours) it turns on reading ~32F as it is well insulated and sealed. Might be an option / energy saver for you and others to look into.

First 48 hours of the Reflectix test. The fridge is using a consistent 12 Amp Hours per 24 hours.

0900 13.0V 0 Ah
1125 12.86V 1.33 Ah
1440 12.92V 3.67 Ah
1712 12.91V 5.34 Ah
2008 12.79V 11.42 Ah
0900 12.76V 12.04 Ah
1100 12.77V 12.75 Ah
1300 12.75V 14.00 Ah
1600 12.71V 16.52 Ah
1840 12.70V 18.11 Ah
2045 12.62V 19.39 Ah
0740 12.61V 23.41 Ah
0900 12.57V 24.00 Ah

Great work, ski3pin! Good enough to qualify as an R&D scientist/engineer!

This makes me think that I should do similar tests with my Indel/Isotherm CR130 fridge. I already have two Watts Ups, to monitor/record the energy each of my two solar panels are putting into my system...I guess I need to get one more to monitor energy use.

From a suggestion from Alley-Kat, I am also now measuring the actual interior temperature and comparing it to the set temperature on the controls. Thanks to Alley-Kat for the loan of this highly accurate scientific refrigerator thermometer.



For the first test I suspended the bottle probe so that it was at a middle point down into the cabinet.



I know the perspective of the photo does not show this well, but I do want to document know this was done.

I put the thermometer in the fridge around noon yesterday, let it come down to temperature over six hours (probably did not need that long but this length of time removed any inaccurate high reading). I reset the high/low last evening at 7:30 pm and checked the thermometer at 7:30 am this morning, a 12 hour period. The fridge remained closed and covered with the reflectix case. The photo above is the results - a low of 37.45° and a high of 43.41°. This gives an average temperature of 40.43°. The controls were set at 36°.

I have moved the bottle probe to the bottom (coldest spot) in the cabinet and will check on the actual temperature there next.

Continuing the power use test results. This is the complete 72 hours of the test run with the reflectix cover:

0900 13.0V 0 Ah
1125 12.86V 1.33 Ah
1440 12.92V 3.67 Ah
1712 12.91V 5.34 Ah
2008 12.79V 11.42 Ah
0900 12.76V 12.04 Ah
1100 12.77V 12.75 Ah
1300 12.75V 14.00 Ah
1600 12.71V 16.52 Ah
1840 12.70V 18.11 Ah
2045 12.62V 19.39 Ah
0740 12.61V 23.41 Ah
0900 12.57V 24.00 Ah
1148 12.57V 25.41 Ah
1400 12.56V 26.96 Ah
1600 12.53V 28.68 Ah
1730 12.53V 29.50 Ah
1930 12.51V 30.96 Ah
0730 12.43V 35.53 Ah
0900 12.41V 36.19 Ah

I continue to average 12 Amp Hours per 24 hours. During the last 24 hours the cover was removed and the lid opened 5 times. The fridge remained closed during the first 48 hours. It is notable that this had very little effect on the power use.

Previous mid cabinet temperature results were a low of 37.45° and a high of 43.41°. This gives an average temperature of 40.43°. The controls are set at 36°. I got this result from the bottom of the inside cabinet space - a low of 37.74° and a high of 42.04° that gives an average of 39.89°. The difference is 0.54° colder at the bottom. But, the recorded low was warmer and this is only one test. What I would deduce from the readings thus far is the temperature looks pretty darn equal in the main fridge area. I am currently running a temperature check on the separate internal area above the compressor.

I did a several hour test of the secondary compartment. It is the gray area to the right.



The bottle probe was placed in the bottom of this area on top of the thermometer itself. The low was 52.03° and the high 53.47°. This gives an average of 52.75°. This reading is 12.75° above the 40° in the main compartment when the control is set to 36°.

I continued the power usage test for 4 days - reflectix cover and temp on the controls set at 36°. This is the complete results:

0900 13.0V 0 Ah
1125 12.86V 1.33 Ah
1440 12.92V 3.67 Ah
1712 12.91V 5.34 Ah
2008 12.79V 11.42 Ah
0900 12.76V 12.04 Ah
1100 12.77V 12.75 Ah
1300 12.75V 14.00 Ah
1600 12.71V 16.52 Ah
1840 12.70V 18.11 Ah
2045 12.62V 19.39 Ah
0740 12.61V 23.41 Ah
0900 12.57V 24.00 Ah
1148 12.57V 25.41 Ah
1400 12.56V 26.96 Ah
1600 12.53V 28.68 Ah
1730 12.53V 29.50 Ah
1930 12.51V 30.96 Ah
0730 12.43V 35.53 Ah
0900 12.41V 36.19 Ah
1650 12.35V 41.46 Ah
1800 12.34V 42.24 Ah
0730 12.24V 47.59 Ah
0900 12.24V 48.10 Ah

This shows an average power draw of 12 Amp Hours per 24 hours. Occasionally opening the fridge on the third day barely increased the power usage.

I have run the fridge for the last 48 hours with the controls set on 34° to do an actual inside temperature test. The power usage has remained at 12 Amp Hours per 24 hours. Temperature test results are coming.

I have completed two tests of the temperature inside the main compartment with the temperature control set on 34°. First - low of 36.35° and a high of 40.87° for an average of 38.61°. Second - low of 36.75° and a high of 40.31° for an average of 38.53°. This is a pretty consistent temperature average.

So comparing the previous results it appears that the actual inside temperature is 4° to 4.5° warmer than the set temperature.

36° set temperature = 40.16° inside
34° set temperature = 38.57° inside

I would say this is probably the most scientific study done on this particular fridge out there.

Another WTW first.

On my TF65 at 3.5 on the dial it holds a very steady 40 degrees. Of course temps have been mild lately.

ski3pin said:

I have completed two tests of the temperature inside the main compartment with the temperature control set on 34°. First - low of 36.35° and a high of 40.87° for an average of 38.61°. Second - low of 36.75° and a high of 40.31° for an average of 38.53°. This is a pretty consistent temperature average.

So comparing the previous results it appears that the actual inside temperature is 4° to 4.5° warmer than the set temperature.

36° set temperature = 40.16° inside
34° set temperature = 38.57° inside

Click to expand...

Ski,nice of you to take the time to do all the testing.Here in the wilds of Minnesota the fridge has been working great.The wife said it's the best thing since sliced bread.We have had no trouble with it,holds the temps nicely and makes no noise.We keep it in the truck behind the seat.The Igloo thermo cooler made much more noise.
Frank

These should be my final test results. One note - these tests have been done with the fridge in the camper in the spot it will be used. I set the temperature control at 32° and ran the fridge for over 24 hours starting with the battery fully charged. I did open the fridge a few times during this test.

1300 13.0V 0 Ah
1430 13.0V 1.37 AH
1840 12.9V 4.46 Ah
0825 12.77V 9.65 Ah
1330 12.77 12.48 Ah

I took three readings of the inside temperature

low 33.54° and high of 38.58° for an average of 36.06°
low 33.71° and high of 38.24° for an average of 35.97°
low 33.27° and high of 38.24° for an average of 35.76°

This confirms the control set temp is about 4° lower that actual inside temperature.

Bumping the temperature control down to 32° from 36° increased power usage by .48 AmpHours

36° set temperature = 40.16° inside
34° set temperature = 38.57° inside
32° set temperature = 35.93° inside

My conclusions is the the fridge will use 12.5 AmpHours per 24 hours. For budgeting/planning for our power use I will use the conservative figure of 15 AmpHours per 24 hours. I will use the fridge set at 32° to achieve our preferred 36° fridge inside temperature.

One side note. We use an inside/outside thermometer with a remote we mount in a spot under the cabover. I put the remote in the fridge to compare it's reading to the actual temperature. It reads 1.4° high. So on a trip, if need be, I can check the inside temperature using the remote.

I have wired in a dedicated 12V circuit to run the fridge with. It will not have my Watts Up meter wired into it. I will be checking power use the old fashion way by monitoring the battery voltage.

I wish there was a spot in each circuit, especially the old forced air furnace with the fan, where I could hook in the Watts Up to really get an accurate assessment of individual appliances power draw over 24 hours. Up to this point, most of the reading I have done on line are based on good guesses/estimations.

I know there are a couple of high priced meters available to measure usage/load at the battery. I just don't think our little camper needs that level of sophistication to justify the price tag. That's one of the reasons I took the time to take my measurements as I did.

I hope that you have found this test and the results of value.

ski3pin, thanks for this good information. I have a new dometic fridge which I think is very similar if not the same as this one. I have noticed the same temperature differential between the fridge setting and the actual inside the fridge temperature. I don't have a watt meter so I am very appreciative of the test results. We are planning to use our fridge occasionally as a freezer on longer trips. I wonder if you have any interest is running a test with the fridge set at 0 degrees with a couple of frozen gallon water jugs inside to check the energy useage for that scenario. -Al

<snip> I wonder if you have any interest is running a test with the fridge set at 0 degrees with a couple of frozen gallon water jugs inside to check the energy useage for that scenario. -Al


takesiteasy, I'm sorry but I've already converted my 12V supply line into my dedicated circuit for the fridge and taken the Watt Up meter out. Shucks. I had no plans to use the fridge as a freezer, so it didn't occur to me to do the test. It would have been a good one. I would need another 12V supply line to wire in the Watts Up meter to do this test sometime in the future.

Ok, no problem. I suppose I could get my own watt meter- but I will probably just watch the battery. Thanks, Al.