tx2sturgis said:
Sorry folks, math and (typing!) is not my strong suit.
23 vans like mine would be needed to move 45,000 pounds of cargo, making the total fuel cost $1403...
Ouch!
Apartment fridge install
- Thread starter Sabatical
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Sorry folks, math and (typing!) is not my strong suit.
23 vans like mine would be needed to move 45,000 pounds of cargo, making the total fuel cost $1403...
Ouch!
highdesertranger said:
But most of our calculations here are based on buying new stuff...
I might also be able to buy a used dorm fridge for $25 at a pawn shop, and a used 500 watt inverter on Craigslist for $40...but I'm doing all the calculations with new equipment.
Buying good used hardware, when you can, would sure help save money in all aspects of keeping our food cold...
SternWake said:
That's what we're working on here: its an experiment, to gather data. Whats wrong with that? There may actually be more than one clear path, more than one way to 'skin a cat'.
You certainly have a valid point with the kill-a-watt used to measure inverter output to the fridge...it would make more sense to use an amp-meter inline with the inverter on the DC line.
FWIW, I'm not advocating this as 'better' for anyone...just a viable alternative if Sab can make it work, and he's happy with it. I'd like to follow along.
If it's a dismal failure...so be it...hes out a couple hundred bucks of food and a fridge that can sell for $50 on Craigslist, and we all learned something.
BTW any old fridges should be taken to a metal recycler, not dumped in a landfill...just sayin.
And none of us plan to stfu.
highdesertranger
R.I.P HDR
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I did try to use a dorm fridge and ice chests and RV fridges and peltier coolers. IMHO they were all a waste of money. if I just would have bought a 12v unit to begin with I would be dollars ahead. also I bought my first 2 12v refers new. I mentioned the last 12v I bought used to show people that if you look around you can find used units for a lot cheaper then new. I bought my solar to run the dorm refer that didn't work out, so I didn't have to buy solar for the 12v. the same panels that would not keep up with the dorm fridge work fine with two 12v refers.
I am just trying to help people not make the same mistake I did. if you all want to use the dorm refers that's fine. I am just relating my experience, I didn't need data I had real life experience.
highdesertranger
I am just trying to help people not make the same mistake I did. if you all want to use the dorm refers that's fine. I am just relating my experience, I didn't need data I had real life experience.
highdesertranger
highdesertranger said:
Good point, I would think its probably much wiser in the beginning to buy a dedicated 12v fridge if it will do what you want as far as capacity. I never said otherwise.
If someone randomly asked me how to keep food cold in an RV using solar only, I would absolutely steer them to a nice compressor fridge like the Whynter, Engel, ARB, or Indel-B units. But the OP had already begun this project when we all joined in.
Since I use HF receivers and high power ham radio transmitters when boondocking, I need to consider the compatibility of electronic devices and the job they do. So I would tend to avoid the computer controlled 12v fridges, since none of them are rated for near-field RF exposure or emitted RF noise.
But DC to AC inverters are a HUGE noise problem for nearby HF receivers, so its a bit hard to solve the problem, from over a keyboard anyway.
In a month or two I guess we will all know the results. In the meantime I'm all eyes wide open!
Hey guys, lets not steer this useful thread into the crapper...
Thor and his hammer are only a couple of steps that way >>>>>>>>>>>
<<<<<<<<<<<<<< Or is it that way?... :huh:
Anyway, its only a dorm fridge...let's pretend its not that important to be right.
_______________________________________________
"All you need in this life is ignorance and confidence, and then success is sure."
---Mark Twain
Thor and his hammer are only a couple of steps that way >>>>>>>>>>>
<<<<<<<<<<<<<< Or is it that way?... :huh:
Anyway, its only a dorm fridge...let's pretend its not that important to be right.
_______________________________________________
"All you need in this life is ignorance and confidence, and then success is sure."
---Mark Twain
Wow if that can actually capture and hold transient current spikes, fantastic! I've read only very expensive gear can do that.SternWake said:
Any steps toward taking the guesswork out of minimum-sizing inverters would be very helpful.
Of course the quality chasms between cheap and well-respected brands still leaves a lot of variability.
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bardo said:
Having known several people who bought a $500 compressor fridge and then replaced it a year later, I have to say there is a lot of logic to this way of thinking.
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First, I deleted a whole bunch of over-the-top posts.
Anybody goes back there gets a warning.
There is no excuse to get this emotionally involved in a discussion about electronics!! Until a couple of you went totally crazy it had been a very useful and helpful thread. Had you guys not lost your minds we were on our way to actually getting some answers to a tough but important question, is a dorm fridge a viable choice for a vandweller/nomad?
I get it, you already know the answer and you just want to protect the rest of us from throwing our money away. The problem is there are people who are having good luck with them, and I don't think they are liars and fools. I want to hear from them without them being shouted down. So you are just going to have to tolerate this thread because I like the idea of doing real experimentation.
I happen to know Sabbatical and know he is a very smart and honest guy whose opinion I totally value and trust. A genuinely good guy--I personally don't know any better.
I find it incredible for him to be attacked under any circumstances, especially UNDER THESE where he is just here trying to help people.
This kind of disrespect towards others is totally unacceptable and will not be tolerated.
Anybody goes back there gets a warning.
There is no excuse to get this emotionally involved in a discussion about electronics!! Until a couple of you went totally crazy it had been a very useful and helpful thread. Had you guys not lost your minds we were on our way to actually getting some answers to a tough but important question, is a dorm fridge a viable choice for a vandweller/nomad?
I get it, you already know the answer and you just want to protect the rest of us from throwing our money away. The problem is there are people who are having good luck with them, and I don't think they are liars and fools. I want to hear from them without them being shouted down. So you are just going to have to tolerate this thread because I like the idea of doing real experimentation.
I happen to know Sabbatical and know he is a very smart and honest guy whose opinion I totally value and trust. A genuinely good guy--I personally don't know any better.
I find it incredible for him to be attacked under any circumstances, especially UNDER THESE where he is just here trying to help people.
This kind of disrespect towards others is totally unacceptable and will not be tolerated.
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Obviously, I am a fan of 12-volt compressor fridges since I've owned three of them. However, I know all too well that most people can't afford them so I want to see if dorm fridges can be a valid option.
Sabbatical, please keep us posted on what you are doing, you can help a lot of people with your findings.
I think I'll start a thread and buy one myself and see how it works for me. I have enough solar to play with I can find out what will work and what won't.
Sabbatical, please keep us posted on what you are doing, you can help a lot of people with your findings.
I think I'll start a thread and buy one myself and see how it works for me. I have enough solar to play with I can find out what will work and what won't.
Sabatical
Well-known member
I am awestruck by your words. Thank you.
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Expressing qualified opinions can be very valuable, but ongoing experimentation should be encouraged.
Some shore power fridges do seem to be reasonably energy efficient, and I love the idea of a 12V thermostat turning the inverter on/off.
Would be great to collect a list known-good but cheap inverters that can handle the startup surge.
And of course collect info on how the fridges hold up bouncing down the road.
My own pet experiment will be a small unit freezing polar tubes to go into in a super-cooler, maybe converting an ice maker.
Also DIY conversion of a custom made ice box, ideally scavenging the guts from old/used/cheap fridges.
Finally, came across this, seems flexible, maybe worth saving for: https://www.whynter.com/product/whynter-62-quart-dual-zone-portable-fridge-freezer/
Some shore power fridges do seem to be reasonably energy efficient, and I love the idea of a 12V thermostat turning the inverter on/off.
Would be great to collect a list known-good but cheap inverters that can handle the startup surge.
And of course collect info on how the fridges hold up bouncing down the road.
My own pet experiment will be a small unit freezing polar tubes to go into in a super-cooler, maybe converting an ice maker.
Also DIY conversion of a custom made ice box, ideally scavenging the guts from old/used/cheap fridges.
Finally, came across this, seems flexible, maybe worth saving for: https://www.whynter.com/product/whynter-62-quart-dual-zone-portable-fridge-freezer/
Trebor English
Well-known member
Back to the subject of measuring surges, from a prior thread,
Since I am more interested in 12 volt amps I have a different way to measure surge. I have a Fuke model 189 (obsolete, discontinued) multimeter that has the ability to record maximum and minimum. It also has a fast max and min that gives up a digit of precision to get more speed. It only goes to 10 amps so I have a .001 ohm external shunt resistor. That gives 1 millivolt for each amp. So I set the meter to measure millivolts. So that the meter doesn't spend time autoranging I manually set the range.
It is quick. When my Harbor Freight 400/800 inverter gets connected to the battery there is an arc as the input cap charges. If it has been disconnected two days I get 190 to 196 amps. If it is disconnected while running, to run down the cap, and left disconnected just a couple of minutes the reconnection surge is only 145 to 150 amps. Turning on the inverter with no load causes a surge of 77 to 79 amps. With no load after the surges the inverter takes .4 amps and the Haier 1.7 cubic foot fridge takes 6 amps running.
I just got the solid state relay. My plan is to have the inverter start surge and the compressor start surge be separated by 5 seconds so that 40 amp fuses don't blow and then the $20 inverter will be enough. Having all the surges at the same time makes the compressor hum and not start.
Brad KW said:
Since I am more interested in 12 volt amps I have a different way to measure surge. I have a Fuke model 189 (obsolete, discontinued) multimeter that has the ability to record maximum and minimum. It also has a fast max and min that gives up a digit of precision to get more speed. It only goes to 10 amps so I have a .001 ohm external shunt resistor. That gives 1 millivolt for each amp. So I set the meter to measure millivolts. So that the meter doesn't spend time autoranging I manually set the range.
It is quick. When my Harbor Freight 400/800 inverter gets connected to the battery there is an arc as the input cap charges. If it has been disconnected two days I get 190 to 196 amps. If it is disconnected while running, to run down the cap, and left disconnected just a couple of minutes the reconnection surge is only 145 to 150 amps. Turning on the inverter with no load causes a surge of 77 to 79 amps. With no load after the surges the inverter takes .4 amps and the Haier 1.7 cubic foot fridge takes 6 amps running.
I just got the solid state relay. My plan is to have the inverter start surge and the compressor start surge be separated by 5 seconds so that 40 amp fuses don't blow and then the $20 inverter will be enough. Having all the surges at the same time makes the compressor hum and not start.
jimindenver
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I nearly put a Edgestar 3.1 ft two door mini fridge in my trailer. Its rated .64a @120v is the lowest you can find and is not that much more than a larger 12v compressor fridge. Like the low draw A/C units you pay extra for the energy savings. I did not end up with it because I could never find one in my area and I realized I needed freezer space and 2/3s of this unit was refrigerator. There were some 3 or 3 1/2 ft mini chest freezers for under $100 at Home Depot that I wish I could have checked out. It may have had a higher draw than the Engel I use now but it also had a lot more insulation. In fact it would be interesting to see a long term comparison between a energy star mini freezer and a 12v compressor unit. My Engel is cool to the touch and cycles a lot.
Jax Austin from the youtube channel Jax across America uses a two door mini fridge like I mentioned but of a different brand. He has 300 watts of solar and a single Lifeline 8-D. Those two doors range from .64 to over 1 amp at 120v. Most good mini fridges are near .8 amp or 8 amps at 12v. The worse are the mini cubes that almost always rate at 1.5a @120v. They are made cheap and efficiency is not a thought. In comparison you can find 9 or 10 ft two door apartment fridges that use the same amount of power or little more.
A killawatt is great at what it does but a clamp meter on the line running into the inverter from the battery. When I say my little A/C pulls 33 amps it includes the inverter.
Jax Austin from the youtube channel Jax across America uses a two door mini fridge like I mentioned but of a different brand. He has 300 watts of solar and a single Lifeline 8-D. Those two doors range from .64 to over 1 amp at 120v. Most good mini fridges are near .8 amp or 8 amps at 12v. The worse are the mini cubes that almost always rate at 1.5a @120v. They are made cheap and efficiency is not a thought. In comparison you can find 9 or 10 ft two door apartment fridges that use the same amount of power or little more.
A killawatt is great at what it does but a clamp meter on the line running into the inverter from the battery. When I say my little A/C pulls 33 amps it includes the inverter.
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