Refrigerator

[Propnut]

Ever since reading OC Divers post about the Summit Refrigerator he installed and reading everything I can find about how to make a marine refrigerator cool properly I decided it would be easier to just copy Mr. Divers solution and purchase a Frost Free Summit Refrigerator with an ice maker. It’s ordered. Once it arrives I’ll take some before pictures and I’ll take pictures thru the install process. I’ve got new polypropylene water tanks. I’m going to install a 3M water filter for the ice maker. 3000 watt inverter is already installed on the boat. I do plan on purchasing a small portable inverter to have on the boat so in the event my main inverter fails , I’ve got a backup for the fridge. Wish me luck! I’ll let everyone know how this project turns out.

[O C Diver]

Congratulations! Hope the install goes well. Is your inverter pure sine wave?

Ted

[Alaskan Sea-Duction]

following

[Dwk]

Friends purchased a Summit fridge for their cabin and are surprised with the lower lower amp draw(500 watt pure sine wave inverter) compared to the previous fridge.

[Propnut]

Inverter is a pure shine wave

[Propnut]

It was a process, but the new refrigerator is installed and working great!

[kthoennes]

Yep, we did the same thing last summer. Dumped the Norcold and bought an LG 7.0 cubit foot high efficiency fridge on a dedicated inverter with an auto-transfer switch for a small fraction of the price of a new marine 12/110 fridge. Incredibly more efficient, draws 25 watts when it's cycling according to my meter. I keep thinking that meter has to be off but I've tested it three times and used somebody else's meter once just to make sure. Heck, just one single 20 watt G4 bulb (all replaced with LED's now) pulled almost as much as the refrigerator, and it freezes an ice tray solid in about 30 minutes.

[O C Diver]

Originally Posted by Propnut

It was a process, but the new refrigerator is installed and working great!Attachment 123021

Congratulations!
It's amazing how much less power a well insulated refrigerator uses.

Ted

[O C Diver]

Originally Posted by kthoennes

Yep, we did the same thing last summer. Dumped the Norcold and bought an LG 7.0 cubit foot high efficiency fridge on a dedicated inverter with an auto-transfer switch for a small fraction of the price of a new marine 12/110 fridge. Incredibly more efficient, draws 25 watts when it's cycling according to my meter. I keep thinking that meter has to be off but I've tested it three times and used somebody else's meter once just to make sure. Heck, just one single 20 watt G4 bulb (all replaced with LED's now) pulled almost as much as the refrigerator, and it freezes an ice tray solid in about 30 minutes.

As much as I would like to have a refrigerator that draws 25 watts, I think that's wishful thinking. What is your compressor on / off cycle time? What does your inverter say? If it has a display, it generally will tell you amp draw. My refrigerator usually pulls 11 amps at 12+/- VDC. That would equal about 132 watts when running.

Where / how are you taking your wattage measurement?

Ted

[Mako]

What is the auto transfer switch for?

[O C Diver]

Originally Posted by Mako

What is the auto transfer switch for?

When it senses shore or generator power it switches to that instead of inverting from the batteries

Ted

[sbman]

Originally Posted by O C Diver

As much as I would like to have a refrigerator that draws 25 watts, I think that's wishful thinking. What is your compressor on / off cycle time? What does your inverter say? If it has a display, it generally will tell you amp draw. My refrigerator usually pulls 11 amps at 12+/- VDC. That would equal about 132 watts when running.

Where / how are you taking your wattage measurement?

Ted

My Magic Chef 9.9 cu ft draws 7 DC amps and the inverter delivers 84W, with a loss of about 4 watts in the inverter. It runs enough to consume 850W per day on average.

25W does seem very low, but if it's a newer inverter style it may draw 25W continuous instead of cycling with a variable speed compressor.

[kthoennes]

Originally Posted by O C Diver

As much as I would like to have a refrigerator that draws 25 watts, I think that's wishful thinking. What is your compressor on / off cycle time? What does your inverter say? If it has a display, it generally will tell you amp draw. My refrigerator usually pulls 11 amps at 12+/- VDC. That would equal about 132 watts when running.

Where / how are you taking your wattage measurement?

Ted

Well, I am talking about 25 watts at 110v (from the inverter) - so that's what, about a quarter amp at 110, so that's 2.0 amps at 12volts? But then I suck at electrical math, I shouldn't even try it, I'll only sound stupid. But I agree, either way, I thought that couldn't possibly be right, couldn't possibly be that low, but a few things have reassured me it may be right, or at least close. First, I used one of these, twice, both times starting the fridge from room temp for one hour.

https://www.gardnerbender.com/en/p/P...e-Power-Meter#

When it was running that meter showed it was pulling 25 watts. It cycled off after about 22 minutes starting from room temp and then didn't come on again for the rest of the hour. Of course this isn't NASA precision, people open the door, the (2-watt led) light goes on inside, varies by ambient temperature, and it's not quite full size, 7.0 cu ft., etc. Regular residential size usually starts around 10 cu ft or more I think. Our big honkin' high-end fridge at home is about 25 cu ft, so the boat fridge is small, but it's certainly not dorm-room tiny or a half fridge. But next, just in case that GB meter was inaccurate, I borrowed a Klein AC/DC clamp meter and got about the same result. And then LG's specs say it uses 220 kWh per year, which works out to what -- about 91 watts? Again, my electrical math may be off and I don't know how LG tests the consumption, but for me at about 75* in the cabin, once it comes down from starting room temp the fridge would then cycle about 10 - 15 minutes per hour. By my calculations, 25 watts for say 15 minutes per hour year round 24/7 is actually less than 220 kWh. The thing is so darn quiet it was very hard to tell when it was cycling, but I could see that GB meter jump from almost zero to 25 when it did cycle on.

Either way, compared to the dinosaur Norcold, it's amazingly efficient.

[O C Diver]

Originally Posted by kthoennes

Well, I am talking about 25 watts at 110v (from the inverter) - so that's what, about a quarter amp at 110, so that's 2.0 amps at 12volts? But then I suck at electrical math, I shouldn't even try it, I'll only sound stupid. But I agree, either way, I thought that couldn't possibly be right, couldn't possibly be that low, but a few things have reassured me it may be right, or at least close. First, I used one of these, twice, both times starting the fridge from room temp for one hour.

https://www.gardnerbender.com/en/p/P...e-Power-Meter#

When it was running that meter showed it was pulling 25 watts. It cycled off after about 22 minutes starting from room temp and then didn't come on again for the rest of the hour. Of course this isn't NASA precision, people open the door, the (2-watt led) light goes on inside, varies by ambient temperature, and it's not quite full size, 7.0 cu ft., etc. Regular residential size usually starts around 10 cu ft or more I think. Our big honkin' high-end fridge at home is about 25 cu ft, so the boat fridge is small, but it's certainly not dorm-room tiny or a half fridge. But next, just in case that GB meter was inaccurate, I borrowed a Klein AC/DC clamp meter and got about the same result. And then LG's specs say it uses 220 kWh per year, which works out to what -- about 91 watts? Again, my electrical math may be off and I don't know how LG tests the consumption, but for me at about 75* in the cabin, once it comes down from starting room temp the fridge would then cycle about 10 - 15 minutes per hour. By my calculations, 25 watts for say 15 minutes per hour year round 24/7 is actually less than 220 kWh. The thing is so darn quiet it was very hard to tell when it was cycling, but I could see that GB meter jump from almost zero to 25 when it did cycle on.

Either way, compared to the dinosaur Norcold, it's amazingly efficient.

Ok, watts are watts. If you have a device consuming 240 watts, it's 20 amps at 12 volts or 2 amps at 120 volts.

If LG says it consumes 220 KWH per year, that would be .60 KWH per day (220÷365=.60). There are 1,000 watts in a kilowatt. So that's 600 watts per day. From there your hourly consumption is 25 watts per hour (600÷24=25). Assuming your refrigerator is on approximately 33% of the time, it should be drawing about 75 watts while running. That's before the inverter conversion loss of about 10%. I would guess if you were to measure DC amps flowing into the inverter when the refrigerator was running, you would see a draw of 6 to 8 amps.

Now that's outstanding!

As a point of comparison, my 10 cuft. refrigerator has an annual power consumption of 297 KWH.

Ted

[catalinajack]

This is easy folks. The comparison is watts to watts comparing fridges of equal cubic feet. I just went through this discussion on another forum comparing a Summit 4.2 c.f. fridge to a Vitrifrigo of the same size. The bottom line is the Summit consumes twice as much energy as compared to the Vitrifrigo when the V is running on AC. When the Vitrifrigo is run on 12VDC, the Summit consumes triple the energy and that doesn’t even factor in the inverter loss. You cannot escape the law, Ohm's Law. Now, you may not care about the difference but some will for reasons other than initial cost. No amount of rationalizing or but, but, butting can change the laws of science.

[O C Diver]

Originally Posted by catalinajack

This is easy folks. The comparison is watts to watts comparing fridges of equal cubic feet. I just went through this discussion on another forum comparing a Summit 4.2 c.f. fridge to a Vitrifrigo of the same size. The bottom line is the Summit consumes twice as much energy as compared to the Vitrifrigo when the V is running on AC. When the Vitrifrigo is run on 12VDC, the Summit consumes triple the energy and that doesn’t even factor in the inverter loss. You cannot escape the law, Ohm's Law. Now, you may not care about the difference but some will for reasons other than initial cost. No amount of rationalizing or but, but, butting can change the laws of science.

Show me the yellow energy consumption label. Amperage draw of the compressor is meaningless without factoring in duty cycle. Pretty simple for them to submit a unit for independent testing.

Ted

[kthoennes]

Here's mine. Not much in the way of actual consumption specifics, but here's the yellow sheet.f92da493-28d4-4a2a-9c92-2126fd3d5a91.pdf


https://images.thdstatic.com/catalog...26fd3d5a91.pdf

[BruceK]

Originally Posted by O C Diver

Show me the yellow energy consumption label. Amperage draw of the compressor is meaningless without factoring in duty cycle. Pretty simple for them to submit a unit for independent testing.

Ted

Interesting. A brand of appliances here provided refrigerators for testing which were found to have "unusual" settings producing "unusually favourable" draw results. Thereafter the tester organization began acquiring that brand of refrigerator to test from stores, not from the manufacturer.

[O C Diver]

Originally Posted by kthoennes

Here's mine. Not much in the way of actual consumption specifics, but here's the yellow sheet.Attachment 123039


https://images.thdstatic.com/catalog...26fd3d5a91.pdf

Actually yours is very specific. With the standardized federal test, yours consumes 220 KWH per year (600 watts per day). The rate of consumption when the compressor runs is meaningless. If a compressor draws 50 amps at 12 VDC but only runs 1 hour every 24 hours, it's drawing 600 watts. If a compressor only draws 2.084 amps at 12 VDC when running, but runs continuously 24 hours a day, it's drawing 600 watts also. Having a somewhat larger compressor means that when adding warm groceries or making ice, the refrigerator can pull the warm items cold faster do to extra capacity.

Here's the Energy Guide from my refrigerator.



Ted

[Propnut]

Originally Posted by O C Diver

Actually yours is very specific. With the standardized federal test, yours consumes 220 KWH per year (600 watts per day). The rate of consumption when the compressor runs is meaningless. If a compressor draws 50 amps at 12 VDC but only runs 1 hour every 24 hours, it's drawing 600 watts. If a compressor only draws 2.084 amps at 12 VDC when running, but runs continuously 24 hours a day, it's drawing 600 watts also. Having a somewhat larger compressor means that when adding warm groceries or making ice, the refrigerator can pull the warm items cold faster do to extra capacity.



Here's the Energy Guide from my refrigerator.



Attachment 123040



Ted

All I know is the beer is cold, the ice cream is hard, it’s making plenty of ice.
I don’t have to defrost it and I’ve got plenty of power to run it. What’s not to like about it ?