 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Electronics : Solar refridgerator inverter selection.
  Page 2 of 3   |
|||||
| Author | Message | ||||
| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
It should be quite simple to find a battered old refrigerator that still works, and do exactly as Klaus has done. Carefully strip everything not needed away from the working parts, and start from there. Once again Klaus, very well done !! Cheers, Tony. |
||||
Lapsy Senior Member  Joined: 28/01/2012 Location: AustraliaPosts: 103 |
The plan B idea has swayed my thinking a little. Have now been looking at the 3 way fridges that can also handle LPG. Some can run for 30 dys on 9kg of gas. Locally a gas fill is about $30-$35 but could maybe get it cheaper if I look around or go for the swap bottles. (Waiting for my gas cylinder to get about 9 and a half years old then I will swap it in a gas bottle swap (Servo or the like), instead of paying to get it tested). LPG seems like a nice plan B backup if your 12v is sluggish in cloudy weather. I am not needing a fridge for a family or to stock a months worth of food. I shop daily pretty much, so it's not a massive deal. Just sometimes you may scoop a bit of bargain meat and buy more than you need (Just coz it's cheap) and may want to store it for a day or 2 longer. I am not hunting, trying to stuff a deer in a freezer in the middle of the bush. Just mearly in it to save a bit of money and cut a few costs if it can be done. All ideas welcome! Keep em comming! Klaus! Any pictures of you D.I.Y Cooler!? This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
||||
| Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462 |
Going this way, your PV system can be for 1 to 2 days greatly reducing cost of batteries to store energy for periods of bad weather. (Just draining 20% of total power, 12V battery system could be 400Ah and this would greatly increase longevity of deep cycle batteries). Heard of 3 way fridges, but did not read about them. Interesting 3 way fridge can be used on gas just one day from time to time? Switching from grid power to inverter should be OK, suppose it would be quite involved=expensive to make it automatic. George |
||||
| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
O.K, Have been hunting around and scored a Waeco Absorbtion cooler 35Ltr for under $200 New/Used. Runs Mains/12v/LPG. 35 Litres. About half a metre square. Not fired it up yet. Going to build a new circuit dedicated to this. Think it pulls 72w from memory so, should be do-able off solar. No freezer but I can live with that for now. Does anyone have one of these in action running off solar? Tell me more... Talking to you lot on here definatly helped me make a good purchase decision. When you get keen on something you tend to overlook a few things in the heat of the moment. I always try and do as much homework as I can before making a final purchase. Still like Klaus/Tinkers idea, would love to attempt it, but my knowledge on refridgeration is weak, and although confident to have a go, I would make a dogs breakfast of it. That said, it was the 120w running power on Tinkers DIY that rang bells, as it was obvious to lower the power consumption as much as possible, giving more headroom to run it as close to 24/7 as possible. Inverting a fridge without modification tells me (thanks to you lot out there!), I am asking a bit much without a kw of panals minimum. I am just starting out in the solar realm, and definatly have a bit more cash I have to invest. When you lot started out with solar did you buy more appliances than you could run first off!? Disregard that question if you got a package deal. I am starting 1 panel at a time, which should now excuse me from asking stupid questions like an amateur! So.... I now might have a Westinghouse bar fridge/freezer for sale! Considering parting with it. After all, do I really need 3 fridges? Although a spare fridge is a handy thing when the one your using packs in. Suppose I should say offers considered if anyone is that interested in a bar fridge/Freezer (Highly doubt it on this website, seeing as you have to plug it into mains! Ha!). Ah well.....I shall plod along with this beast and see what unfolds. (When I say plod, I should add I have no connection with the South Australian Police force what so ever, except when they fine me the buggars!) This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
||||
| Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462 |
In my humble opinion not too good idea. Just save money for one panel at the time and buy all the panels in one go and you still might be unlucky and have to fight with supplier, to give you all the panels from the same batch with the same cells layout / appearance / colour. Not to mention that they can have slightly different size and output. There is minefield out there with lots of suppliers, vast difference in workmanship, quality …. One of the variables is that different panels have different output tolerances, there can be: -/+ 3% -/+ 5% - 0 /+ 3% -0 /+5% (So 100W panel can be anything from 95W to 105W and 200W panel from 190W to 210W and from what I heard, DC systems work better and last longer if they have well matched components) Cells can be 150mm square or larger or smaller. Panel output can be 18V max, 21Vmax or even 22V something and they are all considered to be 12V panels, not to mention that there are panels for grid connection that give much higher DC voltage. Congratulations on your 3-Way Fridge purchase! Interesting what instruction says about LPG side of your fridge? Can it be put on LPG for few hours only and then put on DC or grid? George |
||||
powerednut Senior Member Joined: 09/12/2009 Location: AustraliaPosts: 221 |
Lapsy if your willing to do some construction work you may want to consider rolling your own. Check out the eutectic fridge options: http://www.ozefridge.com.au/ You may be able to operate that directly from the battery (12v or 24V anyway), which would save your inverter cost and power consumption. Its hard to find power consumption figures (probably because it'll depend a lot on what insulation options you use) on that site, but one guy qoutes 7 watts continous for his 180 litre fridge. So ballpark 168Watt hours/day. no idea if that includes freezer operation. *edit* whups, should have read your last post about buying the 3 way fridge. congrats on that. |
||||
yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
George, you are getting in a lather about nothing with matching panels. Sure if you are building a grid system then it is good to have all panels in SERIES in a string closely matched. When you are wiring parallel for battery charging you can afford to be a lot less picky. say I have 3 mono 5 inch cell 175 watt panels charging a 24 volt battery and I want to add 2 more. I would happily buy any mono panel with the SAME NUMBER OF 5 INCH CELLS right up to 215 watts. you will find if you check the voltages, the higher wattage panel will be a tiny bit lower voltage but other than that they are identical. It is the same cell, they just grade them by output at the factory. I may lose a few watts of potential output but as soon as the controller switches out of bulk charge to absorption the panels are only running at a fraction of full power anyway...for the rest of the afternoon. I guess if I was running 12 volt panels in "series pairs" to make 24 volt I would match the pairs. Its a bit like the 5 days capacity thing, its a bit old school, I don't know anyone that wouldn't start their generator on the morning of day three if the weather forecast was for more gloomy weather. Having said that, I have looked at my records going back six years, I have yet to see three days in a row with almost no sun. I don't see a lot of point designing for more than 60 hours of storage. There is also a set limit for charging amps wet lead acid and gels are 10-13% of the 20 hour battery capacity (C20) AGM's are 20% of the C20 I'm confused, no wait... maybe I'm not... |
||||
| Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462 |
Sorry to worry about nothing and glad that some PV systems are quite forgiving. (It'll be probably better if I just read this thread and not write incorrect statements) George |
||||
| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I think you should keep posting George, this is a brilliant thread because you are all tossing a few ideas around and getting involved. I'm just trying to give you a nudge in the right direction, counting the cells in a panel and estimating the operating voltage is a good habit to get into, if the sticker on the back doesn't match your estimate, there is a good chance your being conned. mono's are just over 0.5 volts per cell Poly's are a little under 0.5 volts. I have been working on a post myself, arguing that the most cost effective thing to do with a fridge and freezer is stay on the grid (if its possible) but the post is a bit rough, I'm having a bit of trouble wording it. I'm confused, no wait... maybe I'm not... |
||||
| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
I should have really said - I'm starting one appliance at a time. I would probably buy the set of panels for the circuit at once but I give anything a go. I am learning so, if you have a bit of everything you can compare it all in the flesh, infront of you. Makes you use what you have too once you have forked out for it. Wanting to do a few seperate circuits, smaller scale. The 3 way I have (Waeco CA-35) I will try dedicating it to it's own set of panels on it's own circuit. Any spare power I could risk slipping another form of charger on the side like a AA or AAA or laptop charger if theres room to max out the usage. So if someone could work out/show me how to/run me through the battery damage on this - 12v, 72w, 6.1Amp - (Max of 15Amp fuse recommended). How many watts in panels to boot this constantly in good weather and what battery would you suggest for best results? Winner or master answerererer to this question will have their answer immortalised in this thread (I think?). 
Also!!! Have you noticed a guy on ebay selling the battery fluid chemical mix to restore your batteries? Anyone messed about with this? It's about 12 Bucks to restore up to 8 batteries. This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
||||
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Coming up tomorrow, I just came across your message and its now too late to take pictures in my shed. BTW, your bar fridge would make a *great* donor for a DIY fridge like I made. You need patience to strip it without breaking anything. A good pair of heavy duty tinsnips & hacksaw is what I used to open the outer metal skin. Power saws cut too easily through unseen copper tubing within  .
You might also find surprises while doing so like I found a frozen lump of ice deeply embedded in the insulation in what must have been an air bubble once. How the ice stayed frozen in there for days until I got around to strip the fridge I don't know. Anyway, you might aim for 2 - 3 times the internal box volume of the original bar fridge with your DIY chest fridge design. You need basic woodworking skills, some tools to cut plywood, glue & insulation. You are aiming for an airtight box or as close as you can get to that so your work needs to be square and close fitting. I try to take some close ups how the piping runs into the fridge and of the compressor/ condenser assembly next to it. Watch this thread  Klaus |
||||
| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Just found a killer Solar Panel Calculator online. Check it out.... Solar Panel/Appliance calculator Also..... If you like the model fridge I got. I just went to Supercheap Auto and they sell it new for $265 at the moment in S.A. BUT GET THIS!!!! Supercheap also sell a brand called mobicool. They also make/have a 35litre 3 way that is VIRTUALLY IDENTICAL (even the instructions look almost the same! I say Waeco even made this one!) for $199. SO there you go! I am still up on these prices though so all sweet! This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
||||
| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I am wondering if my fellow 4M members have considered the alternative. What about installing a grid solar system to offset some of the power usage from the house as well as the low energy cooler and freezer. The Small scale Technology certificate (STC) scheme still has some reasonable cash available till June 2013. Plus the Feed in Tariff in SA is 16+9.8 = 25.8 cents this financial year and 16+11.2 = 27.2 cents next year. I have done a quick calculation for my area if it was installed this month. On a 2.1 Kw solar install I would be credited 117 STC's. At today's price of $30.50 that is $3,568.00. Feed in tariff or equivalent power saved till the end of June $450.00 Feed in tariff or power saved 13/14 financial year $700 - $800 total $ return after first 18 months $4768.00 installation cost panels and inverter $2350 - $ 3750 (depending on inverter cost) tin roof rails, cable ,breakers, warning stickers$650 freight and insurance $350 feed in meter $400 Labor and Electrical contracting $1500 ?? So after 18 months I will still be out of pocket by $500 to $1250 but I will have the potential to knock a minimum of $500 per year off the power bill every year.( probably closer to $800 but I don't Know what the tariff will be after July2014) I reckon that a low energy fridge and freezer would reduce my bill by $200 per year (my fridge is 13 years old and the freezer is over 20 years so they are about due for replacement anyway) What do you think about them apples?  Is that as cost effective as going off grid with the fridge 
cheers from the devils advocate Yahoo I'm confused, no wait... maybe I'm not... |
||||
| Lapsy Senior Member Joined: 28/01/2012 Location: AustraliaPosts: 103 |
Any cash saving in your pocket is a plus. Better than giving it away to a utility company for the sake of it. Their bills are just going to keep on comming at you, as long as your using it. Would be good if you could go to the markets or someting on the weekend and get some cheap electricity, simmilar to how we may buy fruit and veg to save a buck. Powers only going up in price as we all well know. May as well start getting into some form of renewable energy sooner rather than later. This is my signature ---> Scribble, scrawl, a bit of light pencil shading, some indelable ink and a bit of caligraphy. |
||||
norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Ok going to throw my 2bob into the refrigeration-solar debate. My off-grid solar system has run complete house with(18yr)420l two door(cyclic), (8yr)300l upright frost free freezer, and a 100l Norcold(my build 12v) bar fridge. This time of year batteries go to a low of 90 to 92% (ie 10-8% capacity used)(plenty of sun in sunny NQ). For the real interesting info, just replaced the 420l cyclic with a 420l 2door frost free refrigerator, now the batteries drop to 94 to 96%(ie 6-4% capacity used.) Sort of throws a spanner in what has always been a myth, frost-free consume more than cyclic(in 2 doors). They DO NOT and the reason is very simply, refrigeration evaporators are much more efficient if kept frost free.ie the bigger the frost build up on an evaporator the longer the compressor must run to remove the heat due to the insulation effect of the frost build up(and a little more but for the sake of simplicity will leave at that). Thus the power used for the electric heaters(140watt), the heaters heat load and the fans are easily offset by the frost free evaporator effiency. Adding to this effiency is the use of R600 refrigerant. Using 3way refrigeration on a solar-battery setup is simply a backward step, their power consumption on electricity will illustrate this. The modern day 240v household refrigerator has become very efficient and no doubt with competition and energy awareness will become even more efficient. The Waeco 12-24v compressor driven units are far more efficient, than their 3-way models. We come from the land downunder. Vic |
||||
| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
If a guy was going to build his own home built from scratch refrigerator, even the 140 watts continuous heater power could be dispensed with, by using two completely independent refrigeration systems and alternating them maybe daily. Defrosting the evaporator would be an extremely slow process without the heater, and the refrigerator maintained at say +5C. But if a second refrigeration unit takes over each 24 Hours (?) that should be long enough to defrost the "other" evaporator even at +5C. Don't plan to do this myself, just kicking around a few blue sky ideas. In summer it probably does not matter, but in cloudy winter with very low insolation and the compressor not having to work very hard, that continuous useless 140 watt load would be a killer. Cheers, Tony. |
||||
| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
The 140watt heater is only on for a few minutes twice a day, not continuous. Apologise for not being clearer in my first post here. My opinion is you will not build more efficient refrigeration than the manufacturers unless you have their resources. I back this opinion with 20 years of manufacturing under the Aussie reg. name Norcold(79 TO 99), I built low voltage units for solar households but mainly for 4WD and camping. Some with 150mm of insulation. Part way through those years, solar households evolved from low voltage refrigeration to 240v. Not only because of the cost to build one up units but also for the effiency gains that the manufactures had made and also the massive gains made in inverters. I am not knocking build your own projects but I doubt you will be able to compete with the resources the manufacturers have thus the ability to achieve the efficiency they have. I guess what I`m saying is I know from my experiences, I`ll use and back the manufacturers such as Electrolux (Westinghouse,Kelvinator) Added point there on purchasing my new fridge I looked at the energy ratings and settled for a compromise, the best energy rating in the size I wanted cost $1200 plus, the one I purchased was $800. We come from the land downunder. Vic |
||||
| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Are you absolutely sure about that ? Every frost free refrigerator I have ever seen has had the heater constantly running whenever the compressor is not running. As the compressor cycles fairly frequently, so must the heater to keep the evaporator frost free. The way that is done, is to connect the evaporator heating element directly across the motor contacts in the thermostat. Whenever the motor contacts are open, the heater runs. When the thermostat contacts close, the compressor starts up, and the heating element turns off. Cheap, simple, and nasty. I have never seen any kind of timer associated with this, either electronic or mechanical. If such a thing exists, I would be really interested to know how it works. Cheers, Tony. |
||||
| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Heater runs on a timer, either twice or 4 times a day in the older models(80-90`s).Absoutely on those I worked on Kelvi`s, Westinghouse`s etc. The newer models of today, not having worked on them cannot say, but will get back to you after I have a peek at the newie, that is if the cricket gets boring  We come from the land downunder. Vic |
||||
| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Absorootly on the newie too!. Never heard of frost free without a defrost timer, (but than I`m a plumber turned into fridgee) Tony, can you elaborate on the ones you`ve experienced.
3 for 63 our lads are going well. We come from the land downunder. Vic |
||||
| Page 2 of 3 |
|||||
 Print this page |
