Max Burton fridge/freezer

[anm]

it turned to slush it didn't freeze solid.  highdesertranger

Yep and then very quickly froze solid... do I have to submit a picture?

 

[anm]

I've continued testing the Max Burton fridge/freezer, this time using the freezer compartment as a freezer. I set the temp to 15°F and put some frozen food into the freezer. The ambient temperature was 74°F. At 15°F the compressor duty cycle is about 33% on (11 minutes) and 67% off (22 minutes) and maintains the freezer temperature between a low of 12°F and a high of 17°F. I also monitored the temperature of the fridge compartment which was fairly constant at about 41°F.

The freezer compartment is about 10.5" x 10.5" x 11.5" (W x L x D) which I find is more than enough room for me. The refrigerator compartment is 11" x 5" x 6" (W x L x D) which will probably be ok unless you want to put a case of beer in it, then you might need to use the freezer as a fridge too.

Tomorrow I'll try it in a higher ambient temperature.

 

[SternWake]

Do you have any interest in testing to see how much electricity it consumes over a given time span?

The following linked wattmeter has many clones, hook it inline on the DC power cord, if interested:

Last time I hooked mine inline, my Vitrifrogo c51is averaged 0.62 Ah consumed each hour over a 3 day period with 75F max day and ~60f lows maintaining 32.5f.

I do have extra insulation and very good condenser ventilation.

https://www.amazon.com/dp/B017YCTRKK?psc=1

 

[anm]

Do you have any interest in testing to see how much electricity it consumes over a given time span?

The following linked wattmeter has many clones, hook it inline on the DC power cord, if interested:

Last time I hooked mine inline, my Vitrifrogo c51is averaged 0.62 Ah consumed each hour over a 3 day period with 75F max day and ~60f lows maintaining 32.5f.

I do have extra insulation and very good condenser ventilation.

https://www.amazon.com/dp/B017YCTRKK?psc=1

Hey SternWake, yes I will do that, I want to be able to continuously monitor it for a while...

 

[SternWake]

The wattmeter linked has an internal shunt on the (-) wire, The + can be sourced from anywhere, mean ing the + wire does not 'have' to flow through the wattmeter. Inside the + wire has some insulation stripped from it and is soldered to the circuit board. The wire is not cut.

I know this as I have replaced the 12awg leads with 8awg as I use mine on my 40 amp battery charger and 12AWG gets too hot passing that much current.

These wattmeters might or might not be able to accurately read currents below 0.15 amps. I have had some that could and others that would not.

The one I use now cannot read my 0.03 amp internal fan or the ~0.02 amp draw of the compressor controller as it awaits a signal from the thermostat to add on, So I add on 1 AH each 24 hours when i make that 0.62 AH average claim.

I use 45 amp Anderson powerpole connectors on most devices so I can hook up the wattmeter up easily and see what that item draws. I do not condiser them 100% accurate, but averaging somewhere between 85 and 95% depending on the load they are measuring.

Windynation sells a clone version with 8awg leads, and this one reads small currents nicely, but something is very OFF with the KWH and AMP HOUR figures, as they read less than half of actual consumption, yet the instanteous watts volts and amps figures displayed are all fairly accurate. Something is off in the software which counts current passed over time on the windy nation unit.

The most accurate clone I owned was the Andoer version which I no longer own. I currently employ the GTpower clones.

All these clones are taken from the original 'watts up' version which I can no longer find a link to.

Some of these clones will also display the time since they were powered up. Mine do not, well the windy nation one does, but with the WH and AH figures being soo off I do not reallly employ it other than seeing instant amps watts or volts.

 

[Ballenxj]

Hey SternWake, yes I will do that, I want to be able to continuously monitor it for a while...

I'd be interested in the results.

 

[John61CT]

These wattmeters might or might not be able to accurately read currents below 0.15 amps. I have had some that could and others that would not.

I got a great eBay deal on a Victron BMV700, so maybe I'll get a spare shunt and wire the BM to be able to log amps passed for any load or charging source.

 

[anm]

I got a great eBay deal on a Victron BMV700, so maybe I'll get a spare shunt and wire the BM to be able to log amps passed for any load or charging source.

That looks like a nice meter, but kind of pricey for me. That being said, I went through 4 different Chinese meters until I found one that "might" be accurate enough — there's the 45 day shipping time to put up with too — as well as what to do if it doesn't work, one that I got was doa.

I also just today saw this: www.ebay.com/itm/122446409220 
It's just an ammeter, comes with the shunt and is -100A - 0 - +100A, I'm tempted...

 

[anm]

Do you have any interest in testing to see how much electricity it consumes over a given time span?

The following linked wattmeter has many clones, hook it inline on the DC power cord, if interested:

Last time I hooked mine inline, my Vitrifrogo c51is averaged 0.62 Ah consumed each hour over a 3 day period with 75F max day and ~60f lows maintaining 32.5f.

I do have extra insulation and very good condenser ventilation.

https://www.amazon.com/dp/B017YCTRKK?psc=1

I got this meter today and spliced it into the power lead to the to the fridge/freezer. As soon as I verify its operation I'll start logging data...

 

[anm]

I have some grub in the freezer so I am running it at 17°F rather than the 32.5°F SternWake used, but here are my figures:

For a 24 hour period I used 240 Wh, or 10 Wh per hour.
When the compressor is running the fridge freezer draws about 3 A at 12.5 V or 37.5 W.
Since the measured average hourly power usage is 10 Wh the duty cycle works out to about 26% which is close to what I measured by timing it a few days ago so it seems like the 240 Wh measurement is reasonably accurate, assuming the meter is accurate, but the Aervoe literature says a maximum of 3.8 A power draw, and the meter is maxing out at 4.6+. There's a minor discrepancy there...

My house battery is a single 50Ah LiFePo4 that is rated at 650Wh so I could run it for 2+ days with no charging, but with solar panels and the southwest sun the daylight hours are usually free...

I apologize in advance for any mathematical errors, my figuring ain't what it used to be...

 

[Tomcor]

How do you convert wh (watt hours) to ah (amp hours) ?
How many ah did it use in the 24 hour period?

 

[John61CT]

Watts divides by (12) volts ==> Amps

 

[anm]

How do you convert wh (watt hours) to ah (amp hours) ?
How many ah did it use in the 24 hour period?

As previously stated, divide Wh by voltage (~12.5) to get ah.
And in the 24 hour period my meter logged about 240 Ah so divided by 12.5 V gives 19.2 Ah...

 

[SternWake]

As previously stated, divide Wh by voltage (~12.5) to get ah.
And in the 24 hour period my meter logged about 240 Wh so divided by 12.5 V gives 19.2 Ah...

or about 0.8 AH consumed each hour.

Does the compressor on your fridge start out a cycle at say 35 watts and finish up at about 27 watts by the end of the cycle, or is it steady wattage draw the whole time the compressor is running?

My wattmeter only counts upto 64AH before flippinig back to zero, so I was using about 3 days to get an average consumption of 0.62 during my test.  I was adding 1AH to the readings every 24 hours over what the wattmeter displayed.

I hope to add another bulb seal to my door and increase the door insulation at some point too, despite already low consumption numbers.

My numbers were with about 1/2 inch of frost build up on cold plate, which reduces efficiency as the heat drawn from box has to get through the insulating ice layer, which takes more energy.

 

[anm]

or about 0.8 AH consumed each hour.

Does the compressor on your fridge start out a cycle at say 35 watts and finish up at about 27 watts by the end of the cycle, or is it steady wattage draw the whole time the compressor is running?
...

There is some variation in the power drawn but I was assuming it was due to the inrush when the compressor starts. I'll try monitoring the meter and see if it does that...

 

[anm]

...
Does the compressor on your fridge start out a cycle at say 35 watts and finish up at about 27 watts by the end of the cycle, or is it steady wattage draw the whole time the compressor is running?
...

Here are the readings I got:
42.5 W at start, this figure varies quite a bit due to exactly when the reading is taken (not under my control) in relation to when the compressor switches on, it varies anywhere from 35 to 57 W, we could probably assume the higher figure for the inrush.
Then the power slowly builds up, 13.7, 16.2, 18.8, 24, 27.5, 30, 32, 33.7 W, this rise in wattage occurs over a few seconds and I think is due to me running the freezer on the A/C power supply plugged into household current.
And it peaks at around 35.4 +- 5 W until the compressor turns off.

I'll charge up my jumpstart battery and try running it off that...

 

[SternWake]

Interesting.

My wattmeter shows a peak amps and peak watts. My peak watts were 56.5 IIRC. My vfc51is, after the surge, starts at 37 watts and tapers to 27 watts about 5 minutes later at end of compressor cycle.

I have one wattmeter, that when on my schumacher smart charger, the readings jump all around 90% of the time when schumacher is seeking a voltage. I bring this up as the schumacher is a pretty dirty power supply. If you are running your fridge from an ac/dc power supply perhaps it too is dirty and the wattmeter on the DC output, is getting confused by the noise. I have other wattmeters unaffected by dirty schumacher.

Your jumpstarter pack should always be top charged, like all resting lead acid batteries. Any lead acid battery sitting at less than full charge is losing capacity at a greater rate than a fully charged one. the lower and longer the faster the capacity loss and with that goes the loss of cranking amps, whch might render the jumper pack useless in its original intended use, when required.

 

[jimindenver]

I noticed that the Max Burton unit is now $325 up from $295

 

[anm]

I noticed that the Max Burton unit is now $325 up from $295

Yeah it is, but they also have the 53 qt fridge/freezer for $359 (on eBay), either seems like a good deal to me...

 

[anm]

...
Your jumpstarter pack should always be top charged, like all resting lead acid batteries.  Any lead acid battery sitting at less than full charge is losing capacity at a greater rate than a fully charged one.  the lower and longer the faster the capacity loss and with that goes the loss of cranking amps, whch might render the jumper pack useless in its original intended use, when required.

Yes well I think it's finally died, I would not be able to start a car with it, though I can briefly power a device that needs a low current draw...