12v Refrigerators

[Tango]

I am installing a Whynter dual zone (fridge/freezer) but only after talking to several blue water sailors who have been running them. They LOVE'em. Very impressive performance. Will freeze stuff solid in 30 minutes from start-up and keep it there with a very low draw.


I was sold. Gotta have some ice cream on board!

[kazetsukai]

Originally Posted by Sasquatters

Can you give more information on this? I am still learning so it is all a bit confusing

Your charge controller should have little to do with what you can draw from your battery. I do not use the "output" or "device" connectors on the charge controller to draw from- I go straight to the battery. To me, a charge controller's limits have only to do with PV input.

I have both a Renogy 40A MPPT charge controller and a Victon Energy 100A charge controller. Your 60A charge controller is, frankly, wasted on a 12V system. Bump up to 24V and then use step-downs in parallel to meet your 12V needs. What's this about an alternator?

Originally Posted by JDOnTheGo

Remember that some items (like computers) draw more power when battery is low than they do when near full.

This is all items and due to Wattage = Voltage * Amperage. As the batteries deplete, voltage drops. If your appliance draws 14W, it is going to do it at 14V (full) with 1A, or 12v with 1.16A, 10V with 1.4A and on. Higher amperages require thicker wires and will heat those wires more, therefore is less efficient.

I can't help but note your picture of your panels: When any part of a panel is covered, it is going to produce close to nothing for you. If you plug two 10W panels in series (20W) and cover a single cell of one panel you're going to see close to no production from both panels- this is because one will block the other. If you plug them in parallel you'll see 10W. This is why parallelization is highly desirable if you're going to have mixed coverage.

So for your panels, keep in mind:

2x 10W (10V, 1A) panels in parallel makes for 20W (10V, 2A).
2x 10W (10V, 1A) panels in series makes for 20W (20V, 1A).

Running your panels in series is more efficient as voltage drop from cable runs will affect you less. The drawback is you'd better keep every panel in a series in the clear.

As for the original question, I'm buying a pair of the Dometic Dual Zone chest fridge/freezers. They're incomparably more efficient than anything I've seen- even my current 600W system will run them in perpetituity with ease.

[davisdesigns]

I was having the same delama and couldn't find what i wanted for $500 or less as i'm not willing to spend more on some sheet metal, foam and a compressor. So i decided to make my own.

Making a chest fridge/ freezer, Its not as complicated as most think. I have it assembled minus the interior stainless steel, haven't got around to design it yet. But i did test it with MAP gas as a refrigerant and it works way better than R134a but i will be using propane/ butane mix not the MAP gas, it may turn the compressor oil.

Anyways the most efficient and cheap way is to use a chest freezer modded with a $13 controller

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I tested it before removing the evaporator, it worked awesome but i need a freezer so i gutted it and made my own evaporator, not rocket science.... Anyways its way more efficient than anything you can buy because 1. it's a chest and the cold doesn't run out when you open the door and 2. i'm using propane as a refrigerant (R290) which is way more efficient than R134a. plus i'm only invested $160 so far not including the stainless steel and gas shocks for the lid that will lift the food trays up.

I ultimately wanted a 48V DC compressor but couldn't find one for less than $500 so i'm using the original 120VAC one for now. I'm setting up for a 48V DC solar and will convert anything over to 48 VDC, pretty much anything with a motor, almost all electronics are actually DC anyway so inverting DC to ac than converting it to DC just doesn't make sense to me.

[Sasquatters]

While I appreciate everyone's opinion on the chest freezer type setup, this is absolutely impossible for our current setup. We do not have the floor space, and considering the buss is nearing completion, I do not want to start to rip up wood and change the layout. We have the space for a stand up refrigerator since that is what we framed for. A chest freezer just can't happen. I am very interested in that converter however.

[o1marc]

Originally Posted by Sasquatters

While I appreciate everyone's opinion on the chest freezer type setup, this is absolutely impossible for our current setup. We do not have the floor space, and considering the buss is nearing completion, I do not want to start to rip up wood and change the layout. We have the space for a stand up refrigerator since that is what we framed for. A chest freezer just can't happen. I am very interested in that converter however.

Chest freezers come in many sizes, I'm sure they make one that would fit your fridge hole.

[Sasquatters]

Originally Posted by o1marc

Chest freezers come in many sizes, I'm sure they make one that would fit your fridge hole.

Unless it's 24" wide and 61" tall, unlikely 🤷🏻*♂️

[joeblack5]

Originally Posted by PNW_Steve

Victron and others do make 12 volt to 24 volt chargers.

It seems that this victron converter is not really a charger but just an adjustable 24 volt power. so no bulk ..float charging set up. You could do the same with an alternator and a adjustable regulator. Either way it is not going to be fast since it is constant voltage charging.


a 24 volt alternator 55 amp is available for $ 75 if you look around. 24 volt / 12 volt converters are around pretty cheap



I would think that your charger controller is just fine. As JD said your panels producing only 80% of the output being mounted flat and that only for a very short time. So the overall watthour production losses are pretty small.


I have a 1200 watt solar array on a 1000 watt grid tie inverter and it rarely shows a production of 1000 watt .


good luck

[superken]

You can get the 7.7 cu ft norcold 3 way on eBay for $1100. They are GREAT! The dc is 17a 214watts at 12volt, propane or 120v

[gingie]

What is CL..where you said you got your fridges? Thanks!

[gingie]

I'm asking about something that is essentially a foreign language to me but here goes..How many panels do you have for your bus and what brand and size is your inverter? Thanks!

[gingie]

Nevermind! I'll head over to solar!. Thank you!

[o1marc]

Originally Posted by gingie

I'm asking about something that is essentially a foreign language to me but here goes..How many panels do you have for your bus and what brand and size is your inverter? Thanks!

We don't know what foreign language you speak because you haven't filled out your profile in the "UserCP" in the upper left here. If we know where you're from we can better assist you with answering locality related questions. CL is short for CraigsList.

[kazetsukai]

Originally Posted by Sasquatters

While I appreciate everyone's opinion on the chest freezer type setup, this is absolutely impossible for our current setup. We do not have the floor space, and considering the buss is nearing completion, I do not want to start to rip up wood and change the layout.

My (two) chest fridges are going to be on drawers that slide back behind my shower wall when not in use. If I wanted to place them somewhere where they were permanently visible and accessible, I wouldn't have anywhere for them either.

Not saying anything other than that there's usually dead space you can squeeze out of somewhere if you look hard enough.

[Sasquatters]

The panels will likely end up on a tilt of some sort. That will be later down the road. We had the deck built around the solar, so once it was done, we dropped the panels in. Just one more giant thing out of the house.

[Sasquatters]

So I have been using the Kill-a-Watt meter to figure out our exact uses and necessary and I think I stumped myself a bit. I tested the PC for 24 hours, and also for 7 days since someone suggested that you get a more accurate measurement that way. During this time I left the PC on all the time rather than shutting it off at night like it will be while living in the bus. Do I need to redo this measurement, or can we figure it out based of of X amount of hours of use using the 24 hours figure?

I am working on measuring the NAS now and will begin to post some figures when there's enough to start making sense of this all.



Thanks!

[JDOnTheGo]

I think... if it is a desktop, you can do as you say since the power draw is fairly constant. If a laptop, the same might work but I'm not certain. My laptop draws a lot of power when the battery is low and charging, not a lot when battery is near charged. I'm not sure if that averages out over time or not.

[Sasquatters]

Alrighty. Here's the results!

PC 10 hours a day.
24 hours - 1.55kwh
7 days - 10.60kwh

Server 10 hours a day.
24 hours - 2.47kwh

Washer 4x a month.
30 minute - 0.06kwh

Refrigerator will be on a timer at night.
24 hours - 0.60kwh
150w kick on
93w running

I didn't calculate lights but they will all be LED lights and the ones we have are 6w.

Thanks!

[Jeremyc]

Look no further. F235891 AC/DC 42 Quart FridgeFreezer | BaseCamp

got one in ours and it's the BOMB. not on often as very well insulated. Can also be a freezer and has drain plug.

[Sasquatters]

Started a new thread about solar. Thanks guys.

[JDOnTheGo]

Originally Posted by Sasquatters

Alrighty. Here's the results!

Well done!! Nothing beats some actual measured data with which to begin making good, informed decisions!!