Trebor English
Well-known member
233 watt hours per day divided by 12 volts is 19.4 amp hours per day.
DIY: How to make your own 12V Fridge
- Thread starter ViaVacavi
- Start date
Help Support Van Living Forum:
highdesertranger
R.I.P HDR
- Joined
- Apr 4, 2012
- Messages
- 22,892
- Reaction score
- 86
yes and then divide 19.4 by 24 and you get .8a per hour. highdesertranger
AquaticsLive
Member
I will give try running at as a freezer sometime; will have to wait though till I don't have a fridge full of stuff. I will definitely be back to share summer info to know how it will do in the 90's
highdesertranger I guess that is were the math comes out but think its important to tell people that it surges at 8 amps and pulls 6 amps from the battery when running the compressor. So I just want to make sure that there is a disclaimer to it; I have to think before opening it up to reduce the loss of cooling. If your grabbing stuff out allot or its hot in the van when you opening it you have the possibility of it running much more. My guess is that when my son is with me it will be double; two people opening and closing it to get stuff and well since he is a kid not thinking about being quick about getting something.
I think this is a great combo for someone that can find a deal on a dorm freezer. I am very happy with it since I didn't spend much and have a working fridge I live in a college town so was a cheap easy item to get here.
highdesertranger I guess that is were the math comes out but think its important to tell people that it surges at 8 amps and pulls 6 amps from the battery when running the compressor. So I just want to make sure that there is a disclaimer to it; I have to think before opening it up to reduce the loss of cooling. If your grabbing stuff out allot or its hot in the van when you opening it you have the possibility of it running much more. My guess is that when my son is with me it will be double; two people opening and closing it to get stuff and well since he is a kid not thinking about being quick about getting something.
I think this is a great combo for someone that can find a deal on a dorm freezer. I am very happy with it since I didn't spend much and have a working fridge I live in a college town so was a cheap easy item to get here.
Motrukdriver
Well-known member
Would mounting location be significant? Small fridge on the floor vs. mounting it eye level. I wonder if warmer air up high and cooler air down low is enough of an impact to be counted. I would think a chest style fridge would be a touch more efficient as well since you open the top and the cold air inside the fridge stays in place where if you open a front door the cold air would immediately want to flow out to the floor. Just random thoughts here....
That was exactly the factor I mentioned above, very minor.
The key, besides massive insulation, is the degree of ventilation over the hot condenser / electronics area. Ideally coolest air available inbound, venting to back outside in hot weather.
Actively increasing that cooling on stock OTS units will help both effectiveness and efficiency.
An install blocking it will really hurt.
The key, besides massive insulation, is the degree of ventilation over the hot condenser / electronics area. Ideally coolest air available inbound, venting to back outside in hot weather.
Actively increasing that cooling on stock OTS units will help both effectiveness and efficiency.
An install blocking it will really hurt.
Well I got my set up all finished and working.
I have a inverter with "sleep mode" built in so I got one of the STC -1000 DC and ran it off the batteries and when it hit the set temp it wakes up the invteter. Having the inverter on full time used more watts than the actual refridgerator did, the fridge used 360W a day and the inverter used 400W a day. Now that I can used sleep mode the whole system uses 450W to 500W a day. The DC powered STC -1000 was a big help, I expecialy like this temp controller becuase it has a power on & off button so you can turn it off even when the power is still connected.
If your inverter does not have "sleep mode" you can do as they stated above and wire in a 2 terminal mount to the on/off switch wired to the relay on the STCC -1000 temp controller which will turn it on & off when in use acting as "sleep mode".
I set my fridge (which is really a converted upright 2.1 CU freezer) to 28 and set the differentiual to 12 so it does not kick on unitl it reached 40 degrees. This stopped it from short cycling and saved about 33% of the watts previously consumed.
I also ran a Bogart engineering trimetric which is a 500mah shunt based tracker that has Volts, Amps, total AH used. It's very nice to see what the real numbers are and how full my batteries are or how much was used.
Here's some picturesof my set up:
I have a inverter with "sleep mode" built in so I got one of the STC -1000 DC and ran it off the batteries and when it hit the set temp it wakes up the invteter. Having the inverter on full time used more watts than the actual refridgerator did, the fridge used 360W a day and the inverter used 400W a day. Now that I can used sleep mode the whole system uses 450W to 500W a day. The DC powered STC -1000 was a big help, I expecialy like this temp controller becuase it has a power on & off button so you can turn it off even when the power is still connected.
If your inverter does not have "sleep mode" you can do as they stated above and wire in a 2 terminal mount to the on/off switch wired to the relay on the STCC -1000 temp controller which will turn it on & off when in use acting as "sleep mode".
I set my fridge (which is really a converted upright 2.1 CU freezer) to 28 and set the differentiual to 12 so it does not kick on unitl it reached 40 degrees. This stopped it from short cycling and saved about 33% of the watts previously consumed.
I also ran a Bogart engineering trimetric which is a 500mah shunt based tracker that has Volts, Amps, total AH used. It's very nice to see what the real numbers are and how full my batteries are or how much was used.
Here's some picturesof my set up:
Attachments
> Having the inverter on full time used more watts than the actual refrigerator did, the fridge used 360W a day and the inverter used 400W a day. Now that I can used sleep mode the whole system uses 450W to 500W a day.
Note that watts per day does not make sense, same as amps per day.
I'm guessing you mean watt-hours per day?
If this is at 12V then the range is 30-42-63AH per day.
A very efficient, quiet and long-term reliable inverter sized right for the load seems to be the key to this idea, so getting comparisons on specific units that are reasonably priced (Magnums can be more than an Engel) would be very helpful.
Note that watts per day does not make sense, same as amps per day.
I'm guessing you mean watt-hours per day?
If this is at 12V then the range is 30-42-63AH per day.
A very efficient, quiet and long-term reliable inverter sized right for the load seems to be the key to this idea, so getting comparisons on specific units that are reasonably priced (Magnums can be more than an Engel) would be very helpful.
AquaticsLive
Member
Carv Like the nice clean wiring. Think these dorm freezers are the way to go for these systems; takes a little more Craigslist shopping to get one for cheap but worth it. I love mine. Looking at the numbers and they are very similar to the big dollar 12V systems; has me sold on keeping it as my permanent fridge.
I like the sleep mode I have not seen one of those yet in action sounds like a good option for the future if my inverter ever dies.
I like the sleep mode I have not seen one of those yet in action sounds like a good option for the future if my inverter ever dies.
John,
Yes that is 500Wh in a 24hr period which is 42AH in 24 hours for both the inverter and fridge and since I have 520W of grid tires on my roof with a 30A mppt charge controller batteries where full by 11am every day.
Over night (dark at 5:30pm first light at 6:45am) so 13hrs no sun at all and running 12v interior LEDs and a 16ft Led rope light for 3hrs plus I used a total of 17.6AH
Aquatics, I totally agree!
I got mine on CL for $70, I put plexiglass liners on the shelves for $20, and $15 for the temp controller. I can run it at any temp I want considering it's designed to run at negative 14 to negative 21, so cold beer, frozen meat, Or just regular fridge duty I really don't think you can beat it for a $100
Like I said earlier, if you get a simple 2 terminal block and wire one side of on/off switch on the inverter to the separate terminals so each side/positive & negative are septate (just like vanvacari did in his earlier posts & pictures). Then get a 12vDC STC-1000 digital temp controller, run the controller off the batteries directly and wire the cooling terminals on the temp controller to the 2 terminal block you wired in to the on/off switch ...AND....you now have sleep mode on your inverter ? for $17.
The inverter won't be on all the time but it'll save you a bunch of Wh
OR you could figure out how to wire in the switch so you can control the inverter on/off with the switch as well if you want the inverter to be under your control when you want and ran by the temp controller when you don't want to manage it. This is how van vacari did it.
Yes that is 500Wh in a 24hr period which is 42AH in 24 hours for both the inverter and fridge and since I have 520W of grid tires on my roof with a 30A mppt charge controller batteries where full by 11am every day.
Over night (dark at 5:30pm first light at 6:45am) so 13hrs no sun at all and running 12v interior LEDs and a 16ft Led rope light for 3hrs plus I used a total of 17.6AH
Aquatics, I totally agree!
I got mine on CL for $70, I put plexiglass liners on the shelves for $20, and $15 for the temp controller. I can run it at any temp I want considering it's designed to run at negative 14 to negative 21, so cold beer, frozen meat, Or just regular fridge duty I really don't think you can beat it for a $100
Like I said earlier, if you get a simple 2 terminal block and wire one side of on/off switch on the inverter to the separate terminals so each side/positive & negative are septate (just like vanvacari did in his earlier posts & pictures). Then get a 12vDC STC-1000 digital temp controller, run the controller off the batteries directly and wire the cooling terminals on the temp controller to the 2 terminal block you wired in to the on/off switch ...AND....you now have sleep mode on your inverter ? for $17.
The inverter won't be on all the time but it'll save you a bunch of Wh
OR you could figure out how to wire in the switch so you can control the inverter on/off with the switch as well if you want the inverter to be under your control when you want and ran by the temp controller when you don't want to manage it. This is how van vacari did it.
If anyone's solar is switching to Float voltage - when the battery's deeply cycled overnight - in less than 4-5 hours of insolation, odds are good their bank's getting murdered by never really getting to 100% Full.
Which is (should be) defined by endAmps getting down to .005C before dropping from Absorb.
But that's a bit off-topic. . .
Which is (should be) defined by endAmps getting down to .005C before dropping from Absorb.
But that's a bit off-topic. . .
Redbearded
Well-known member
- Joined
- Oct 28, 2017
- Messages
- 173
- Reaction score
- 0
Love the thread!
I also have been looking into this kind of a setup and one of the things I was struggling with is the need for a large inverter to power the fridge due to the startup current. I noticed that you have thought about using a soft start capacitor for the compressor. What do you suppose the savings for power consumption will be by being able to use a smaller inverter? Here is a video describing the process of using a soft start (this one is more complex than a capacitive one). I love the idea of using a 12V relay to control the inverter, I may have to steal that. Another power saving measure (we're getting extreme here) may be to put a timer on the controller for say every 30 min to go on for 30 sec and check if there is a need to run the controller for the next 30 min. Yeah it's only 3W continuous, but power is one thing it's ok to be miserly about, right?
I've actually been considering putting 2 of these together for 2 separate variable units (i.e. dual freezers or dual fridges or one of each). If I get 2 different sizes (like a 3 ft and a 5ft) I can switch them around as things transition fridge to freezer etc. plus I have some redundancy and I'm still under the cost of a tiny Engel or something. This of course assumes that space is not a main concern.
I also have been looking into this kind of a setup and one of the things I was struggling with is the need for a large inverter to power the fridge due to the startup current. I noticed that you have thought about using a soft start capacitor for the compressor. What do you suppose the savings for power consumption will be by being able to use a smaller inverter? Here is a video describing the process of using a soft start (this one is more complex than a capacitive one). I love the idea of using a 12V relay to control the inverter, I may have to steal that. Another power saving measure (we're getting extreme here) may be to put a timer on the controller for say every 30 min to go on for 30 sec and check if there is a need to run the controller for the next 30 min. Yeah it's only 3W continuous, but power is one thing it's ok to be miserly about, right?
I've actually been considering putting 2 of these together for 2 separate variable units (i.e. dual freezers or dual fridges or one of each). If I get 2 different sizes (like a 3 ft and a 5ft) I can switch them around as things transition fridge to freezer etc. plus I have some redundancy and I'm still under the cost of a tiny Engel or something. This of course assumes that space is not a main concern.
Redbearded
Well-known member
- Joined
- Oct 28, 2017
- Messages
- 173
- Reaction score
- 0
Holy crap the electronic one the video is for is like $300, NOPE! I'll buy the dumb one for $15, lol.
hello all , i am new here. found an article about this subject that didn't mention an inverter. just converting a 120 vac freezer to 12 vdc. after 35 + tears in a/c refrig. and electrical this didn't seem possible. the author must have been lapse in their facts, anyhow the set up and freezer and the data seems to be good. emailed the site , waiting for response.i will get model of inverter and how it worked and relay info.
Mod edit. I edited out the link please no links until you have 10 posts.
Mod edit. I edited out the link please no links until you have 10 posts.
highdesertranger
R.I.P HDR
- Joined
- Apr 4, 2012
- Messages
- 22,892
- Reaction score
- 86
here's the link that I edited out,
http://shedheads.net/need-know-buying-12v-refrigerator/
a lot of misinformation in the article. I doubt they did the actual testing themselves. highdesertranger
http://shedheads.net/need-know-buying-12v-refrigerator/
a lot of misinformation in the article. I doubt they did the actual testing themselves. highdesertranger
Redbeard, I wouldn't worry about a hard start capacitor.
I tested mine with a kill-A-watt and or was 1.35A on start up and then it'd drop to .9A after 20-30 seconds.
On the itc-1,000 DC digital temp control I mentioned before, you can set the restart protection delay time length so you shouldn't be re-firing it under high head pressure.
If your really that worried test it to see what it's pulling on start up.
I tested mine with a kill-A-watt and or was 1.35A on start up and then it'd drop to .9A after 20-30 seconds.
On the itc-1,000 DC digital temp control I mentioned before, you can set the restart protection delay time length so you shouldn't be re-firing it under high head pressure.
If your really that worried test it to see what it's pulling on start up.
scottorious
Well-known member
- Joined
- Oct 26, 2017
- Messages
- 64
- Reaction score
- 0
That reddit post was pretty awesome! Certainly makes me consider going the inverter route and a cheap chest freezer. My DC voltage will be 48 volts with my experimental Chevy volt battery pack so I either have to convert 48 to 24 volts for the fridge or invert to 120 volts.
Looks like I'll be looking for an upright 3.5 cubic foot chest freezer like this:
https://www.homedepot.com/p/IGLOO-3-5-cu-ft-Chest-Freezer-in-White-FRF434/203474226
I Just want to see some actual power ratings, not the energy guide posting. If the energy guide posting is anywhere near accurate, though, then that freezer draws just around .5 KWH a day. In converted refrigerator mode hopefully it draws less even with the losses from the inverter.
Might be a worthwhile experiment based on some of these results.
Looks like I'll be looking for an upright 3.5 cubic foot chest freezer like this:
https://www.homedepot.com/p/IGLOO-3-5-cu-ft-Chest-Freezer-in-White-FRF434/203474226
I Just want to see some actual power ratings, not the energy guide posting. If the energy guide posting is anywhere near accurate, though, then that freezer draws just around .5 KWH a day. In converted refrigerator mode hopefully it draws less even with the losses from the inverter.
Might be a worthwhile experiment based on some of these results.
ViaVacavi
Well-known member
- Joined
- Dec 18, 2015
- Messages
- 181
- Reaction score
- 0
I don't get on here often these days, but wanted to stop in to update the thread.
I have one of these conversions that's going on two years of absolutely trouble-free operation, and another on about 18 months. These have performed perfectly for us on the road, and continue to use an average of 30 Amp-hours per day or so!
I have one of these conversions that's going on two years of absolutely trouble-free operation, and another on about 18 months. These have performed perfectly for us on the road, and continue to use an average of 30 Amp-hours per day or so!
ricklapointe
Member
- Joined
- Jun 7, 2018
- Messages
- 5
- Reaction score
- 0
hi
followed entire thread
what happened to AHH ME2 findings on his experiemnted? i need to know what he found out its killing me LOL
his findings on 12v vs. 120 volt fridge usage
followed entire thread
what happened to AHH ME2 findings on his experiemnted? i need to know what he found out its killing me LOL
his findings on 12v vs. 120 volt fridge usage
