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ICC
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# Posted: 19 Jun 2019 05:53pm
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Don't confuse reports that an RV fridge cools faster on propane than on electricity with a comparison of a propane fridge vs a 120 VAC household type fridge that has a compressor.
Most RV fridges cool better on propane than electricity because they just use a small resistance heater instead of the propane flame to make the same absorption system work. That has been my experience of many years. And modern fridges can be highly efficient. Look for linear compressors. Their 10 year warranty sets them apart from the rest of the pack. But, like lithium batteries vs lead, they also cost more than the normal types. Maybe consider using ice and coolers for a year or two, if funds are now tight and the use is weekend only.
A household, compressor type fridge cools faster than any propane fridge I have owned; comparing Servel brand to whatever 120 VAC.
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offgrididaho
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# Posted: 19 Jun 2019 06:01pm
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Quoting: ICC Don't confuse reports that an RV fridge cools faster on propane than on electricity with a comparison of a propane fridge vs a 120 VAC household type fridge that has a compressor.
ICC is right on in the above, only clarification I'll add is that the 2 way RV fridges (12v/120v) use real compressors at both voltages, not the little resistance heater on 12v like the 3 way fridges do. This is why you can't run a 3 way fridge on 12v except when your RV is running or you'll kill your battery in no time.
2 way fridges cool like a real fridge on both 12v and 120v and will run for days on 12v, not hours like a 3 way on 12v.
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Wilbour
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# Posted: 19 Jun 2019 06:07pm
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Quoting: offgrididaho why not just spend less on the fridge and buy more panels" kind of choice...
Someone's been drinking creeky's koolaid ;)
I run a small dorm fridge and charge all my devices, from cell phones to 20v batteries for my tools and all the led lights I need. I watch movies on my laptop.
1kw (now 2 because the 1st one was lonely) 24v system with one 285w panel.
Somewhere you have to find a sweet spot between good enough but upgrade-able.
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zorro
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# Posted: 22 Jul 2019 02:32pm
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So just bringing this back up again
I am trying to add a fridge to my cabin build, but not really sure if this will work or not
• I will likey have around 1050 W panels
• 8 x Trojan Batteries (old style)
• 1000W inverter
• MPPT Controller
I will 99% of the time only be at the cabin from Fri – mid Sunday afternoon and fridge only used during this time……………..i know that it will take some time to get to cooling levels
Only draw on the solar system will be LED Cabin lights, cell charger and that is it
Stove – propane
Well – Generator
Wtaer on demand heater - generator
So I have been looking at this small under counter electric fridge;
https://www.wayfair.com/appliances/pdp/danby-44-cu-ft-compact-refrigerator-dan1396.ht ml
It says the annual energy consumption is around 268kwh per year
https://secure.img1-ag.wfcdn.com/docresources/1741/18/185717.pdf
Would that work based on the above solar set up, or would it simply be too high a draw on the system?
I know I can get a propane fridge, but if the above would work, that would be even better
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zorro
Member
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# Posted: 22 Jul 2019 02:54pm
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Or even this which is less of a drain;
https://www.lowes.com/pd/GE-5-6-cu-ft-Built-In-Freestanding-Mini-Fridge-Freezer-Compa rtment-Black/50288017
236kwh per year?
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offgrididaho
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# Posted: 22 Jul 2019 03:22pm - Edited by: offgrididaho
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Zorro,
I feel your pain, these things are so hard to sort out when you're trying to find solid information.
Can't find any spec on the first fridge you linked for how many amps it draws. Second fridge says it draws 1.5amps, at 120v that is 180 watts, that's scary to me given that an RV fridge draws ~36 watts when it's running.
BUT, then you look at the kilowatts per year ratings and they tell a very different story. The Lowes one says 236kwh per year, that's 646 watts per day, or 27 watts per hour on average, which means to me that it only runs 9 minutes every hour, that doesn't seem very realistic to me but who knows.
So MAYBE we're supposed to assume these are well insulated units that don't run very frequently. My 12v RV fridge in my van runs probably 20-30 minutes of every hour (at 32 watts)... so ~380 watts per day. If the Lowe's fridge runs 30 minutes out of every hour it would use 2,160 watts which would be hard to sustain I would think, but that doesn't gybe with the annual KWH ratings given in the Energy Star documents.
Would you buy the Lowe's fridge locally? Any way to buy it, bring it home, plug it into a Kill-a-watt and run it for a few days using it actively like you would (i.e. putting warm things in there to cool) and see how much power it actually draws? And if it's going to break the energy bank return it?
Have you considered the 12v/120v combo RV fridges? They are very power conscious and work well in my experience, although they are more expensive. Given your use I would steer away from propane if possible as they seem to take a long time to cool down on first use (our cabin has a fullish size propane fridge and it takes a day or so to really get cool, it's fine after that but if you're coming and going turning on and off I think electric would work better for you).
-- Bass
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zorro
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# Posted: 22 Jul 2019 04:47pm
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I really would like the small electric under counter type fridge, for the limited time I will be using it
The idea of purchasing and then plugging it into a kill-a watt meter is a great idea..............think i will try that and get a feel for the impact over say 1 week of use
That should hopefully give me a better/real word idea of daily use
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justinbowser
Member
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# Posted: 22 Jul 2019 08:24pm
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I have a 3.1 cu ft Fridgidaire and running it eats a little over 100 watts.
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offgrididaho
Member
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# Posted: 22 Jul 2019 08:38pm
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Quoting: justinbowser I have a 3.1 cu ft Fridgidaire and running it eats a little over 100 watts.
Any feel for how many minutes out of an hour it's actually running?
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neckless
Member
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# Posted: 23 Jul 2019 02:36am
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you guys can roast me but this is one of the most confusing threads i have ever read and i been hanging at camp for thirty years.....
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zorro
Member
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# Posted: 23 Jul 2019 10:26am
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Ha ha……………..it may be my fault and I am likely asking stupid/basic questions!!
I know almost nothing about solar, though I am trying to learn
My main question here is if a small “energy efficient†fridge like this one here;
https://www.lowes.com/pd/GE-5-6-cu-ft-Built-In-Freestanding-Mini-Fridge-Freezer-Compa rtment-Black/50288017
Supposedly 236kwh per year
Rated at 1.6A/115V
From GE – “The amperage for this unit is 1.3 amps. If you are considering running this appliance on a generator, then the approximate size generator needed to operate a refrigerator is 3000-4500 watts. The running amperage is listed on the rating plate of the appliance. However, the start-up amperage could be as high as 3 times the normal running ampsâ€
If it can be used for 2 or 3 days at camp based on my planned solar syatem of;
• 1050W panels (3 x 350W)
• 8 x Trojan T105’s
• 1000W Inverter
• MPPT Contoller
Only other use of the solar system during that time will be LED lights/cell charging and that is it – everything else will either be propane or generator powered
So what I think may be useful is for me to purchase a kill-a meter (bought yesterday) and one of these small fridges and get some real time analysis of power useage
Hopefully get the fridge at the weekend and then run some tests over 2 or 3 days and post the result back here
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creeky
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# Posted: 23 Jul 2019 11:03am
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That system will run that fridge no problem. Make sure you get a pure sine inverter.
Fridges are tested at 25C and opening and closing the door for a family of 4. My fridge, tested at 311/kwh comes in at more like 175 kwh annual.
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Steve_S
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# Posted: 23 Jul 2019 12:12pm - Edited by: Steve_S
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Have a look at this:
http://www.midnitesolar.com/productPhoto.php?product_ID=683&productCatName=Charge%20C ontrollers%20-%
Price: $ 650.00
Includes:
MidNite KID MPPT charge controller
MidNite Big BABY box
2 of our MidNite MNEPV30 breakers, One for the PV input and one for the battery output
1 of our 63 amp DC ground faul breakers for the PV side of the KID
1 Battery temperature sensor
Conduit and adapters
Wire and strain reliefs ETC
Built in Arlington, WA USA
Warranty - 5 yrs.
Add your Panels, Batteries & Inverter and your off to the races.
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offgrididaho
Member
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# Posted: 23 Jul 2019 12:40pm
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Quoting: zorro it may be my fault and I am likely asking stupid/basic questions!!
You're asking the right questions, it's just never easy to find the right info, especially when you're looking at items that aren't explicitly made for off grid work, so you get lots of conflicting data, often from the manufacturer itself, because most people don't care about a stray electron here and there.
-- Bass
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justinbowser
Member
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# Posted: 23 Jul 2019 10:19pm - Edited by: justinbowser
Reply
Quoting: offgrididaho Any feel for how many minutes out of an hour it's actually running?
Not sure, I'll try to remember to plug it into my Kill-A-Watt when we get back up there next week and check for 24 hours. Right now it probably runs quite a bit as the cabin is really hot inside.
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Brettny
Member
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# Posted: 24 Jul 2019 11:44am
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Quoting: Steve_S Add your Panels, Batteries & Inverter and your off to the races.
$650 for a charge controller is prety steep and the other things you would need could be upwards of $2k
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NorthRick
Member
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# Posted: 24 Jul 2019 03:50pm - Edited by: NorthRick
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Quoting: zorro From GE – “The amperage for this unit is 1.3 amps. If you are considering running this appliance on a generator, then the approximate size generator needed to operate a refrigerator is 3000-4500 watts. The running amperage is listed on the rating plate of the appliance. However, the start-up amperage could be as high as 3 times the normal running ampsâ€
I'd call BS on this. 1.3 amps at 120 volts is 156 watts. Times 3 at start up is 468 watts. A 1,000 watt inverter or generator would have no problem starting that up and running it.
My Honda 2000 handles a 15amp circular saw.
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zorro
Member
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# Posted: 24 Jul 2019 04:50pm
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Thanks for that info
That is why I think i am getting confused, lost and going round in circles - for every point i read that the solar system I will have should be okay, I then get conflicting info.............and you would think that GE would know their unit...............but probably not!
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zorro
Member
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# Posted: 30 Jul 2019 09:56am
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Ok - quick update
Have bought the Kill-a-watt meter
This small fridge will be delivered today;
Danby Designer DCR044A2BDD
https://amzn.to/2Yko4Vz
Supposedly
• 226kWh per year
• 1amp – running
• Not sure about start up
Plan is to run it a couple of days, try to use it as I would normally and report back here for an assessment
I am hoping it works good for my solar set up above
Will let you know
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Wilbour
Member
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# Posted: 30 Jul 2019 10:39am - Edited by: Wilbour
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Depending on the Kill-a-watt meter, you may not see the startup demand. I have a little dorm fridge and contacted the manufacturer who told me what I should have known all along. Right on the back it said the startup was x number of amps. My original 300w Victron Inverter was not up to the challenge. Once I went to 500w it took the surge in stride. I believe the specs from Victron details the running watt limit along with the moderate peak and split second peak ( or something like that)
Most of my research shows that compressors are essentially in classes so mine would probably be very similar to yours.
My blessing was to purchase the items from a local guy who graciously swapped out my inverter for a larger one without blinking.
I encourage you to look at ontariolakeside's setup and watch his youtube channel. His setup is compact and efficient.
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zorro
Member
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# Posted: 30 Jul 2019 08:00pm - Edited by: zorro
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Ok - going to have a look at that Youtube channel
In the meantime, so very early analysis;
I switched it on and watched the Kill-a-meter for the surge
465 watts starting (so my 1000/1500W inverter should cope??).............and then immediately dropped down to around 45watts
Currently it is running and seems to be showing 45watts just running
Will get a better feel tomorrow in terms of totals and come back and update here
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zorro
Member
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# Posted: 31 Jul 2019 06:46am
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Ok
Quick update
As identified above, when switch on it surged for a coupe of seconds to around 465watts and then dropped to around 55watts
After 12 hours........
Total used = 0.22kwh
Will test again tonight after 24 hours
Fridge is really cold and running very quiet
When it needs a “boost†kicks up to about 55watts and then goes back to essentially zero when running
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zorro
Member
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# Posted: 31 Jul 2019 07:37pm - Edited by: zorro
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Ok
so after a 24 hour run period, here is what I have found with this small fridge;
start up - around 465 watts for literally a few seconds
it then settles down to around 50/55 watts till it gets to the pre set temp
I lowered it to as low as it could go and after 24 hours, total use = 0.44kWh
So based on my planned solar set up, I presume this should not be a major issue for me;
3 x 350W panels
8 x Trojan 105's
1000W inverter
MPPT Controller
This will all be backed up by a large generator
it will be used for no more than 2.5/3 days at a time
Only other things that will be in use will be LED lights and maybe cell charging
Any views on this before I keep it or send it back!
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offgrididaho
Member
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# Posted: 1 Aug 2019 10:41am
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Last month I did three days in one spot in our camper van with 100w solar panel, and along with my RV fridge (runs at ~2.7a when running, figure it runs half the time) we ran some lights and a furnace part of the night. Did not have to run the generator. That's with 100 watts, you're talking about 10 times that power, I personally think you're going to be totally fine with this setup.
Worst case scenario, you get no solar for some reason, you still have 10.8kwh from those batteries, 5.4kwh using only 50%, you could run that fridge for almost ten days before you needed outside power.
Some might say your system is oversized, I ended up oversizing ours quite a bit too for two reasons... 1) I was doing the work anyway, adding an extra few panels / extra few batteries wasn't much extra work (although extra $$$) and 2) these places are where we go to relax, right? counting every single watt hour (should I plug in the phone AND the tablet, or just one??) is not relaxing to me.
Nice job with the kilawatt, research is good but real world data is better.
-- Bass
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zorro
Member
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# Posted: 1 Aug 2019 08:23pm
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Thanks for the info - much appreciated
I am a total newbie when it comes to this, so any help, really is invaluable
Everything i have tried to read and understand does suggest i should be okay with this small fridge based on my planned system - so hopefully I am ok
And I agree 100% - my system is over sized for what i need, but my reasons are exactly the same as your
I am doing it now, so build in some "fat"
And I have friends that have systems that every time you switch on a light bulb, they panic and run to switch it off again - THAT stresses me out
As you say, we go to these camps to relax and chill, not to worry about every single watt and light bulb - plus I will have a large generator as back up as required
So hopefully I will be ok
Thanks
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FishHog
Member
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# Posted: 2 Aug 2019 09:14am
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that system will more than run that fridge assuming you get enough sun. You have a generator backup if you don't, so not much risk.
I ran a 12v fridge (I purchased for my van conversion) at the cottage last summer off my 3 x 75w panels. It was dropping the batteries as we didn't have a lot of sun for a few days but caught up on a week of pure sun after.
The only reason I haven't went to an electric fridge yet and still run propane is that I don't what to have to purchase a generator for those low sun periods. Last fall I had almost 1 month of next to no sun and even my lights were draining my batteries.
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creeky
Member
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# Posted: 2 Aug 2019 10:52am
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Quoting: FishHog 3 x 75w panels...no sun and even my lights were draining my batteries
You need more/bigger panels. Zorro will have 10x as many w.
To both of you: Get better batteries. Search scrounge rifle through the web; much better batteries are out there. and the long term cost is many times lower.
Quoting: zorro we go to these camps to relax and chill, not to worry about every single watt
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Steve_S
Member
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# Posted: 2 Aug 2019 12:25pm
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Quoting: zorro So based on my planned solar set up, I presume this should not be a major issue for me;3 x 350W panels8 x Trojan 105's1000W inverterMPPT Controller
I also agree that this setup you have will certainly do what you need, no doubt about it. I don't recall how you were going to mount them up but even a Manual Adjustable ground mount will let you adjust the panels to get more direct sun over the year. A couple of the members here have built some that handle up to 4 panels.
I second Creeky on the batteries, if you haven't got those Trojan's yet, seriously consider alternatives as he mentioned. I have FLA bought 4 yrs ago because prices were very different, adding to them isn't a good option. IF I was spending that $ today, I could get Lithium / LiFePO4 for the same bucks and if I need to addon more later, no issues.
It's a Could've, Should've, Would've but just couldn't at the time & so there's a bit of regret... something No one likes especially if there $,$$$ involved.
Likely mentioned before but with FLA 25% drain is good, 50% drain = harm, Lithium variants 80% drain is good (can be 100% drained but life expectancy triples if 20% charge is maintained EV discoveries).
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FishHog
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# Posted: 2 Aug 2019 01:34pm
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Quoting: creeky Quoting: FishHog 3 x 75w panels...no sun and even my lights were draining my batteries You need more/bigger panels. Zorro will have 10x as many w.
Agreed, I was using my undersized system as an example to show zorro that he will have no issues. My system is very small, it meets my needs now. Will be completely redone when I move to an electric fridge. Just waiting to make that investment
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