Solar Powered Fridge

[jwh92020]

I know this isn't a CTC thing, but you guys are pretty smart here, so I value your opinions. As this build is winding down, I'm planning out my spring build. It will be a 7 x 12 "tiny trailer" (looks like a tiny house but tows like a travel trailer). I have most things figured out, but I'm debating on which 12v fridge to use. The 49 qt Dometic runs $800-$900. It uses very little power, but it's a big chunk of $. I've been looking at the ACOPOWER 12v fridge. I'm posting a link so y'all can read the info and form your own opinions. I would mount a dedicated solar panel on the roof just for the fridge, keeping it separate from the rest of the solar set up. Please take a look and give me your thoughts. Thanks
https://www.acopower.com/product/portable-freezer-refrigerator

[bdosborn]

I have two of them, an upright and a chest style. I'd buy them again in a heartbeat. Yeah, they're kind of spendy, but I haven't bought ice in 10 years.

Power Usage

I hunted around on a bunch of sites before I bought mine, they do occasionally go on sale. Here's a some bookmarks I found that still work:

https://www.pplmotorhomes.com/parts/rv-appliances/rv-refrigerators-freezers/rv-refrigerators-and-freezers/portable-refrigerator-freezers_CF-035AC

http://www.roadtrucker.com/arb-fridge-freezer/arb-12v-24v-fridge-freezer.htm

https://www.amazon.com/Dometic-CC40-ACDC-Portable-Refrigerator-Freezer/dp/B079V4TF4S/ref=sr_1_7?keywords=dometic&link_code=qs&qid=1552150569&s=gateway&sourceid=Mozilla-search&sr=8-7&tag=mozilla-20

P.S. I don't have a separate panel for mine, everything is connected to the battery. Works great.

Bruce

[tony.latham]

...keeping it separate from the rest of the solar set up...

You're not setting up a solar-powered fridge ––it's a battery powered fridge and your battery is charged with solar panels.



Perhaps you are thinking about two separate 12v systems? Two batteries, two controllers, and multiple panels?



Tony

[jwh92020]

Bruce - Thanks for the links. I'll check them out.

[jwh92020]

Tony - Thank you for correcting me. I didn't word the post correctly. The ACOPOWER fridge has a built in charge controller, so just a panel & wires is all it needs to charge. My plan would be to have a single panel dedicated to fridge and 200 watts of panels and 200 amp hrs of batteries. I don't run that much 12v, so 200 watts/amp hrs should bve plenty. If I need the microwave or a/c, well, that's what the generator is for.

[tony.latham]

The ACOPOWER fridge has a built in charge controller,...

I missed the whole shebang!

T

[norcal2]

Some of the new RV's are only supplying 12v compressor refers, and they have had a lot of problems with using to much energy vs how much solar you can leverage to recharge your batteries, i still like my 3 way fridge, works great!

[jwh92020]

norcal2 - This fridgevruns on a built in LI battery that can be charged via solar, 110v or 12v. I would use a dedicated 100 watt panel for the fridge only. That way, the frdge usage won't affect the rest of the trailer's 12v system.

[John61CT]

Sounds like a bad idea to me.

One battery bank, sized for minimum 3-days average Ah usage.

Enough solar to provide 2x that daily consumption per day when insolation conditions are good.

Supplementary inputs from alt while driving, ideally also a portable genny.

If you can't set that up, reduce your consumption.

[Rustic313]

The accopower is cagey about its specs. The smallest unit says it has a 173 WH battery, can accept 10A of solar input at up to 50V (MPPT? who knows? Probably not at this price point...), and discharges at "normal" setting in 10 hours. Its a lithium battery so let's say it discharges to 20% (aggressive).

That means it is using 138 WH (173 x 0. in 10 hours, or 14 watts per hour. That seems really low to me, but we'll roll with it.

To run it 24 hours a day, you'd thus need to provide at least 336 watts each day (14*24). If you assume you have four good hours of sunlight every day, then a 100W panel *should* do that. The problem is that the internal battery won't last long enough to get you from 4 PM (when the sun starts getting low) to 10 AM the next day.

Without knowing more about the specs I'd be hesitant to spend the money on the accopower.

\\\

If you already have 200 AH of batteries, why not just tie into your existing system? I have 200 AH of batteries and it will run a cheap 12V thermoelectric cooler well enough, especially if you supplement for a few hours every other day on the generator or car inverter in the evening. If you buy a bag of ice before leaving, the thermoelectric cooler will keep temperatures food safe for days.

[jwh92020]

This is why I posted here. I am not familiar enough with solar to understand all the intracies of the equipment. This is going to be a new, frame up build, so I can build a system to fit my needs. I haven't had much luck with thermoelectric coolers, but that could be because the bulk of my time is spent in 90+ degree temps when I'm working out of town. I mainly need to run a couple of led lights at night, a 12v water pump, a tv & satellite dish 5-6 hrs/nite (remember - I'm working, not camping) and a fridge. I have a couple of 2.4 cu.ft mini fridges that I could use (only 1). It draws 0.8 amps. My thought was if I didn't dropl $600+ on a 12v fridge, I could put that $ toward a solar system that will do what I need.

[Rustic313]

This is why I posted here. I am not familiar enough with solar to understand all the intracies of the equipment. This is going to be a new, frame up build, so I can build a system to fit my needs. I haven't had much luck with thermoelectric coolers, but that could be because the bulk of my time is spent in 90+ degree temps when I'm working out of town. I mainly need to run a couple of led lights at night, a 12v water pump, a tv & satellite dish 5-6 hrs/nite (remember - I'm working, not camping) and a fridge. I have a couple of 2.4 cu.ft mini fridges that I could use (only 1). It draws 0.8 amps. My thought was if I didn't dropl $600+ on a 12v fridge, I could put that $ toward a solar system that will do what I need.

If you're building this from scratch then skip the AcoPower. You'll be getting batteries and a charge controller anyways for your main system. No need for redundancy. Either get one of the high-end DC coolers, a cheap Thermoelectric, or an energy efficient dorm fridge that will run off an inverter if you don't want to do propane.

To size the solar system:
1) Add up everything you'd LIKE to run. Also add up everything you MUST run (two categories). Your "minimum requirement" should be at least one day of running everything, and a second day of running the essentials. This will be a number in Watts. That method lets you go one day with all the things, and a second day (if its cloudy or whatever) with the essentials.
2) Battery Bank: Your battery bank needs to be twice the size of the answer you came up with in #1 to avoid discharging the batteries more than 50%. More is better.
3) Panels: Depending on your latitude and cloud cover, you'll want enough panels to replace all watts used in a day plus a "Fudge factor" for inefficiences (add 25-100%) in a 5+/-2 hour window. If you're in Las Vegas and camp in the summer you can plan on 7 hours of sun a day. If you're in Maine and camp in the fall then plan on only getting 3-4 hours of sun a day.

As an example, I have a small fairly efficient compressor fridge that runs off the inverter. It pulls an average of 60 watts when its running, and its usual duty cycle is about 40%. So it pulls about 864 watts per day. Let's round that up to 1000 watts, as it works harder in the summer when the trailer is not cooled.

That means I need a battery bank of at least 2000 watts to run it for one day. Safer is 3000-4000 watts. My actual bank is 440 aH of 12v batteries (5280 watts).

I need enough panels to charge at least 1000 watts over about 5 hours. So at a minimum I need to pull in at least 200 watts with panels of perfect efficiency. I actually have about 750 watts of panels because efficiency is anything but perfect.

But until you do the math for step #1 and determine your requirement in watts per day its hard to proceed.

[John61CT]

That's watt hours per day.

If everything is at 12V, Ah per day is easier to grok.

[jwh92020]

I decided to forego the ACOPOWER fridge and put the $ toward a solar set up. According to one calculator I used, to run a 2.4 cuft 110v fridge (24 hrs/day - I have 2 brand new ones in my storage shed)), 2 12v led lights (1 amp - 6hrs/nite), a tv & satellite dish (6 hrs/nite), a 12v water pump (max 15 min/day) and charge my lap top I need 639 amp hrs of batteries and 500 watts of panels. That is going to cost a buck or two, and it seems like a lot of battery and panel compared to what I see some of you guys using. Time for more research.

[tony.latham]

I need 639 amp hrs of batteries...

HOLY BUCKETS!



Tony