Calling wiring gurus! Residential fridge

[senormechanico]

I've had one of these on my boat for several years and love it.


https://www.amazon.com/Tiger-1500W-P.../dp/B008JGE8LE

[sailorchic34]

Originally Posted by icemate

Small dorm refrigeartors are a poor choice. Power hungry and not worth all the extras you need to power it unless you are at dock all the time. Almost all invertors have a 10% loss when going from 12VDC to 115VAC. A nice 12 volt Adler-Barbour will do a nice job with less hassle. You ca. n put small roll up solar panel on deck if needed to keep batteries charged. I installed one on my sailboat and it was still working after living on my boat for 6 years and sailing to Australia from Buffalo, NY

I'm going to disagree on this one. My setup is at least the same energy consumption then a Alder Barbour system. I think it exceeds the typical A/B system.

Mind you, many dorm fridges are power hogs, but the Edgestar is not at all. 70 watts running and only runs 20 minutes in 1.5 hours. In the Delta heat it's still an energy mizer, even with an extra 15 ah a day from the inverter. My batterys are at float by about noon. Use to be 2 pm to float and that's with 14.5 real amps output from the solar panels mid day.

Lets not forget that the A/B systems invert DC to 3 phase A/C so there are loses there too.

[toddster8]

As alluded to above, the insulation of the enclosure and the door is probably more important for energy usage than the exact cooling unit or how it is powered. As long as you have room, you can add insulation cheaply to almost anything... except a dorm refrigerator with the condenser stuck to the back. Although it might be possible to carefully detach that...

[john61ct]

The key factor is how important energy efficiency is to you.

MOST AC dorm fridges are very inefficient.

MOST inverters that are pure-enough sine wave, high efficiency, reliable over time and handle startup surges well, are more expensive than even a pricey 12V fridge.

SailorChic is giving us a combination that apparently works well at bargain pricing.

But those liveaboards with the budget, who really value every AH, will still want to go with a proper 12V DanFoss based unit and 4" of insulation all round.

[Colin A]

Well ideally an inverter charger would solve the problem by allowing to pass the shorepower thru when available. I would do that before I looked at separate auto transfer and inverter.

You can use a DPDT switch to select shore or inverter for the least expensive method. Or interlock a couple of breakers or switches. You would have to actively do the switch but it would work.

Or as already said you can just let the battery charger handle it while on shore power.

[sailorchic34]

Originally Posted by john61ct

The key factor is how important energy efficiency is to you.

MOST AC dorm fridges are very inefficient.

MOST inverters that are pure-enough sine wave, high efficiency, reliable over time and handle startup surges well, are more expensive than even a pricey 12V fridge.

SailorChic is giving us a combination that apparently works well at bargain pricing.

But those liveaboards with the budget, who really value every AH, will still want to go with a proper 12V DanFoss based unit and 4" of insulation all round.

LOL, Being a poor liveaboard cruiser, out on the hook, energy efficiency is very important too me. So is money. So is food spillage. Why would I spend $1000-$1400 on a A/B system that uses the same amount of power overall then my $450 120v fridge inverter system. I've had a A/B unit in the previous boat and it was no more energy efficient then the 120V fridge I have now (with inverter losses).

I do agree that most 120V fridges use lots of power when running. But even my old 120v fridge that was a power hog, only used 55-60 ah a day. At 35-40 ah (includes inverter losses) and a $450 price point, why spend more??. In 10 years time I've spent $620 on two systems (total price) I could buy another fridge and inverter and still be less cost then a AB system that uses similar power (in many cases) and has more maintenance issues (black box burning up, leaking fittings).

What's even nicer with my little setup is I can have ice cream as the freezer section never gets about 28 degrees F. Food Spoilage is zero now also.

Yes the inverter uses a bit of power on standby, but it's minor. The edgestar fridge uses about 1.78 ah per hour (16 run cycles a day x 23 watts+ (1.1ahx24/2 for inverter)). I only count the nighttime inverter loss as daytime loss is offset by excess solar. That's about 42 ah which is really quite good.

It is a viable alternative to a 12V system. Pluses: no black box that burns out, lower maintenance ok the last fridge was no maintenance for 9 years, and now icecream aboard. Even with the inverter loss its no more power use then a good AB system and lower then many 12V systems.

[Ironman162]

I also agree with the small domestic fridge approach and have one myself permanently plugged into the inverter.
My inverter has an ups function built in so that when plugged into shore power, it switches over automaticallly.
This is quite handy because there is no need to run cords at all. Im hardly ever on shore power though as I have a swing mooring at a marina so the fridge runs 24/7 off the batteries via the inverter with no problems at all.
It's been a very interesting post, thank you!

[john61ct]

I did say those valuing every AH, and willing to pay more.

As good as your solution is compared to other AC units, (and sincere thank you for it!) it's perfect for your context, but no one setup will be perfect for everyone.

Some have no room for excess solar, may mean the difference between burning dino juice or not.

Some may want to be able to use their whole box as a freezer.

Some have custom boxes and just want a kit.

etc

[Ironman162]

So very true John61ct, every setup is different as well as very interesting. I added mine for interest only and as boating goes, will prob have to replace it one day anyway with something more modern as mentioned by other posts.

[kmires]

Originally Posted by Ironman162

My inverter has an ups function built in so that when plugged into shore power, it switches over automaticallly.

Yes, I think this inverter that I'm going to try does that as well although it doesn't have a UPS backup battery setup.

Here is the link in case you have any feedback on it. Pure Sine Wave plus auto-transfer switch.

https://www.amazon.com/Power-PWRIX12...ct_top?ie=UTF8

[Ironman162]

Looks very nice and is better than the one I have. Mine is only basically a modified sine wave inverter with a battery charger built in.

I think the continuous cooling fan on the one you looking will get to me though... On the one I have, the fan only starts when needed and even that is quite noisy!

But on the whole I think a switched control system is reliable and secure with less that can go wrong .

[jeepbluetj]

Listen to SC, she's been there and done that.

I have a 10cu ft res fridge in my motorhome. It's always plugged into the inverter. If I ever plugged into shore power, the battery charger would provide enough current to run the inverter - i.e. the horror of taking 120v, making it 12v, turning that back into 120v to run the fridge. But I don't care, battery stays charged. (And I may have plugged into shore power twice since I put the res fridge in).

For the OP - keep it simple. Move the plug from shorepower to inverter. You'll be fine with a dorm fridge for what you want it for.

[BobLoucks]

See my post re solar setup
Search for an energy efficient bar fridge I went with Danby
My inverter is modified wave Cobra 2575 and controller is an intelligent PVM
Spent $250 on the fridge new and about $750 on everything else

[john61ct]

Originally Posted by kmires

auto-transfer switch

That is the proper term for what ironman called a UPS function.

[john61ct]

Do be careful about the quality of the sine wave, sometimes the squarer wave output causes the fridge to pull more power than it does on pure sine.

I've also heard of people putting the thermostat controls on 12V, turns the inverter on and off as needed for the compressor and the rest only as needed.