Advice for a beginner!

Hi,

I am a newbie on here for posting but I have been looking on here for a while. Of all th sites I have been to for information this one seems the most active and gives good advice..so I am going to ask for some recommandatios for what I am doing:

What I have:

4 - 60 Watt panels @ 12 v
2 - 75 watt panels @24 v
8 - 6v trojan batteries ((108 min @ 75amps) wired for 12 v)
2 - 2 sunsaver 10A controllers ( 12 v )
1 - 30 A charger controller ( 12 v )

=============================

Needless to say I have many questions and comments..let me expound:

I want to run a 12 volt wiring..where would be the best place to buy online? I also want a proper buss bar too but have no selection where I am at. The amps will not be high on the individual wiring so I am curious about guage of wire.

I have the house wired for 120v but will only be using that when I want to run my water ( via my generator )..I could not do everything on DC initially but as I scale up I will be converting this to DC as well..the cabin was wired for 120 so I left it as is and will run DC for most everything else.

With the panels I have above what would be the optimum wiring to the batteries..should I get a MPPT and can that convert both 24 and 12 or should I wire the 12s as a 24 and run 24 to the charge controller? What is the best wiring for a 100ft run from the panels to the batteries to charge them?

How many aH do I have with my current bank in the 12v configuration that I currently run?

If I did want to run the batteries to my panel (not connected to grid ) what would be the best inverter < 200 watts? If do run an inverter to the panel can I still run the 12v lighting system at the same time? ( not that I would..but just to know. )

..I know that most of this is vague but I am still learning but now that I have the parts I can finish this off..I am keeping the batteries charged via a trickle charger when the generator runs but I am not currently using the batery bank for anything.

thanks in advance..give me what YOU would do if youhave the time and the gumption!!!
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Advice for a beginner!

    My advice would be to cut to the chase and get an inexpensive, modified sine wave 12v inverter for 120 VAC to run your lights, and separate off your water pump line for gen-only.
    The other problem is you've got two sets of mis-matched panels:
    240 watts @ 12 volts (20 amps) and 150 watts @ 24 volts (6.25 amps)
    You'd need separate controllers for each array however you slice it (now someone will do the math and come up with a reasonable watt/volt configuration that makes me a liar! :D)*
    An MPPT controller is definitely worth it, although they can be expensive.
    Your batteries work out to 432 amp/hr @12 volts, so they'd want a charging rate of 20 to 50 amps to be 'happy'. Your combined panels should manage 32.5 amps @ 12 volts peak, so they should be sufficient. The 12 volt panels alone would do the trick, although just barely. Remember: the sun doesn't always shine full-on the panels. That's the nice part about the MPPT controllers: they give the maximum charge rate possible under varying light conditions.
    If you wire your 12 volt panels in series you can have 48 volt input to an MPPT controller. The advantages are: less current on the down lead and better charging under low-light conditions (you must have more than battery voltage available in order to charge; the nearer the array is to battery voltage, the sooner charging becomes impossible as light drops off).
    What are the controllers you have? The 30A one might be usable for just the 12 volt array. The other two seem a bit light for the current involved.
    Always remember that 'ratings' and 'reality' don't jibe: panels mostly put out less than their rating (about 70%) but they sometimes put out more!
    Anyway, your batteries should be good for 2500 watt/hrs (to 50% discharge) which is quite a lot! It would run 1 CF light for 200 hours without recharging.

    This has either helped, or confused you no end. :D

    *for example you could wire the 12 volt panels two sets in series to get 24 volts, and have them paralleled to make 120 watts @ 24 volts which is 'pretty close' to 150 watts @ 24 and just use one charge controller. Or you could put the 12v in series for 48v @ 60 watts and the 24v in series for 48v @ 75 watt and parallel them through an MPPT controller too. But it's not ideal.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    Depending on the specifics of the panels, wire them all into a mppt controller, (MX60 or eq) then run either 24vdc or 12vdc depending on what you need. (I have found that there are more 12vdc appliances than 24vdc,) I would then invert with a true sine wave inverter of the proper size, and feed the house that way. Running 120vac is both more convienent as well as less line loss.

    It also seems that avoiding ready fire aim might be in order. Figure out where you are going, and then how to get there.

    Tony
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    hey, thanks for the info..Not sure what " It also seems that avoiding ready fire aim might be in order." means..

    Can I run both 24 and 12 into a MPPT with no issues and have it come out as 12V for the batteries..not sure what was meant.

    I got most of the parts secondhand...the 24v panels were only $50 from a guy who had gotten it as a gift..most of the parts were deals that were too good to pass up..but now I either have to get them to play together or sell and go either 24 or 12v...not sure what is best...for my needs I won't require much power so the 240 would initially do and I could sell the 24v and get more 12v..which would you do?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Advice for a beginner!

    An MPPT controller (such as the Outback MX60) can take any DC input up to 135 volts and "sweep" it down to the best charging rate it can come up with for either a 12, 24, or 48 VDC system. Input voltage from the arrays, however has to be equal and preferably so would the wattage (or at least very close). Like I said, wiring all your 12 volt panels in series would give you a maximum of 240 watts @ 48 volts input (nominal - actual numbers vary with conditions). The MPPT controller will convert this to 12 volts @ 20 amps charge rate. That should be just barely enough to handle your 432 amp/hrs of batteries. You could always leave some of the batteries out of teh circuit if the charge rate isn't fast enough (4 108 amp/hr 6V batteries would give you 216 amp/hrs @ 12 volts and you'd be charging at approx. 10% rate).
    Or you could add the two 75 watt 24 volt panels in series for more charge, although the difference in wattage of the two arrays is a less than ideal situation.
    Keep in mind that where the panels are located makes a BIG difference!
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    No offense intended,,,
    Avoiding the ready fire aim in my parlance is try to think things through (using this site amongst other resources) to have a plan before you spend a bunch of money on hardware that you may later regret.

    Too many people have notion of where they want to get to, but have no real idea how to get there. It sounds like you have a collection of inexpensive hardware to start with. Now to figure out what makes sense.

    As for your next question,,, I don't believe that you can run dual voltages into or out of any controller, mppt or otherwise. You can wire you panels into series/parallel array(s) so that you have one voltage coming in, and another going out. (With an mppt controller).

    I suggest that you read the following: http://www.windsun.com/ChargeControls/ChargeCont.htm

    I'm still not sure what you are trying to accomplish here,,Complete off grid house,, reduce your loads on the grid,,,saving money??

    Tony
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: Advice for a beginner!

    You stated everything is second hand. Before we go any farther, let's look at the batteries.

    8 - 6v trojan batteries ((108 min @ 75amps) wired for 12 v)

    You need to do one of two things, get a specific gravity reading or a voltage reading of each battery.

    I have never done a specific gravity reading so will let someone else chime in on that.

    To do a voltage reading, you will need to disconnect the paralleled wires from each group of 2 batteries. Then let them sit for 6 hours. With a digital meter measure each battery. You should see 5.9 VDC to 6.5 VDC .
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    ..thanks for the replies..no offense was taken.

    I do have a plan..to go off grid. I sold my house, bought a camp, refitted it, double insulated and got rid of all electrical components that I had ( basically ). I don't want to buy a system to fit my needs, I want to live with the system and base what I buy based on need. For the last 2 months I have been off grid doing the inside work ( drywall, vapor barrier, insulation, cookstove install, plumbing, etc ). Off grid has consisted of lamps, flashlights and 12v light wired to a crappy car battery that I have been charging with a 15w panel..but its too off grid but my wife and I are moving in the right directio. I am going off grid because I want to mimimize my imprint, energy independence, not giving 3/4 of my mortgage payment to a bank and to do transactions cash in hand...

    I have checked the specific gravity and done a voltage test and everything seems fine but the guy I bought the 12v panels, charge controllers and batteries did not know the value of the stuff so the batteries were basically free if I were to go and buy the panels new ( but the were secondhand and never installed and still in the box unassembled )..so far on everything I have I paid $1650 ( listed below..so yes, a cheap investment so far by my research )..I do think I need a good charge controller, an inverter and wiring but as it is now I am running a light load on the battery bank via a 12v light and I run a trickle charge when the generator is running while we do work for 2-3 hours a night to maintain the charge to prevent drainage ).

    When the propane finally gets installed I will get a propane fridge and tankless hot water heater..

    All of this information has been great, there is nobody local who has any idea so I have had to mine nuggets where I can and this forum has been great.

    What do you guys think, should I sell the 24v and buy more 12v to simplify the system? What would you do?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Advice for a beginner!

    Just to give you an idea ...
    I have a cabin that's twenty miles from the nearest electric lines. I run an electric 'frige, water pump, digester (septic) pump, satellite internet connection with computer and telephone, and lights/radio/et cetera.
    My system has: 4 175 watt 24 volt panels wired for 48 volt feed into an Outback MX60 MPPT controller. This charges 320 amp/hrs of batteries (which are going to be changed; the ones I got are NO GOOD Interstates - I'm going back to Trojans) which powers an Outback FX 3524 true sine wave inverter (TSW is necessary for the pump motors). Back-up power/charging is provided by a Honda EI2000 generator.
    If I were you, I'd keep all the panels as buying new ones is expensive and selling used ones won't net you much. Maybe trade them for more 12 volt panels if someone wants to swap. You can never have too many panels!
    BTW propane refrigerators aren't very efficient and they burn a lot of propane. Getting rid of ours saved a lot on gas, and it doesn't take much electric to run our modern 16 cu.ft. 'frige: 240 watts running (cycles about 1/3 of the time) and a nasty 500 watts when it goes into defrost mode, but that doesn't last long either. Over-all, about 100 amp/hrs per day (varies with ambient temp and how many times the door gets opened).
    Specific gravity reading is simple: get a hydrometer (available at just about any place that sells auto parts), take off the caps, suck up some electrolyte, and read the float. But it sounds like your batteries are good to go.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    Now things make a bit more sense,,, It seems like you are going in the right direction. I am on the fence regarding Propane fridges. I live with them, but if I were starting from scratch I might agree with Caribocoots about buying a GOOD energy star fridge (120vac) instead. As for propane, if you buy carefully, (There are tons of used ones,,, but buy carefully,,, the biggest problem with used ones is if they were run out of level, the cooling unit can be fatally damaged) you can get a pretty good deal. I tend to favor Dometic RV fridges with electronic ignitors so that they shut off as needed. If you then add insulation to the cabinet, and a fan on the evaporator, you can get them to run on very little propane.

    As for you panel collection. If you can make a good trade, go for it, but using the panels you have would make sense IMHO, but buying a good controller.

    The one piece of advice I would give,,, and it is worth exactly what you pay for it,, Your loads WILL increase with time. You will find that living with "one crappy light" will lead to, "boy, it would be nice to have light in the kitchen in the late afternoon". Living with only a battery radio will lead to, "Wouldn't it be nice to have some better sounding music" etc, etc. etc.

    So if you go back to my original point,, if you think your system through, using what you have, and upgrading what you need, you can create asystem that you will grow into.

    Tony
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: Advice for a beginner!
    icarus wrote: »
    The one piece of advice I would give,,, and it is worth exactly what you pay for it,, Your loads WILL increase with time. You will find that living with "one crappy light" will lead to, "boy, it would be nice to have light in the kitchen in the late afternoon". Living with only a battery radio will lead to, "Wouldn't it be nice to have some better sounding music" etc, etc. etc.

    Boy anit that truth. I started with a 45W kit and it morphed into 960 watts.

    Sounds like you got a good deal.

    On the 24V panels, look inside the junction box, do you see 2 or 3 wires, if 3 then you maybe able to wire it as a 12v panel.
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    ..yeah, the backs of the panels is a new adventure for me..More to come when I actually get to that point.

    See as how I have the battery bank is it overly dangerous to buy an inverter and run of the battery pack while I finish installing the panels? I won't run big loads or anything, just lighting really and I intend to trickle charge while I continue doing work so as to not drain them ( every night )...

    If so then I would love some recommendations as to the best inverter under 2000W..I need to hook into a power panel ( once again with no grid tie )..I have a panel dedicated to switching between battery/inverter and generator already installed in preparation for running solar...My requirments are minimal but I do want the best performance for low wattage..As I mentioned I don't intend to run heavy loads initially. What kind of loss can I expect?

    Snowed here last night..around 8 inches with some local power outages..but none for me!!...Although my 'road' had convieniently set up a 'scratch-wash' for me with many overhanging trees covered with snow hanging over the road and I got to knock of the snow with my windshield...it was pretty at least!
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Advice for a beginner!

    inverter - I like the Morningstar SureSine, 300W cont, 600W 10 min surge

    it's pure sine, so everything works off it, and about the most efficient. You may want to look into a 12V LED light, and skip needing an inverter.

    Just be sure your trickle charger is able to get the battery full, and not just partway, otherwise, you will damage your battery (sulphated)
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    I second what Mike has to say about the Morningstar. The other advantage that it has, is that it is one of the few pure sine wave inverters that will allow you to tie the neutral to the grounded bus bar of your house panel. Most small inverters use a floating neutral, and cannot have that neutral grounded,, which makes wiring into a house panel problematic.

    If you do wire into the panel, you will need a transfer switch to allow you to feed the house with the generator as needed. See the host store, NAWS for an IOTA transfer relay,

    Tony
  • SolarJohn
    SolarJohn Solar Expert Posts: 202 ✭✭
    Re: Advice for a beginner!

    I like my Exeltech 1100-watt pure sine wave inverter. For not much more money than a 300 or 600 watt inverter, you'll be able to do more things. The Exeltech is made in the USA, and has impressive specs. Of course it may be more efficient to run a 300-watt inverter closer to it's rated load, but you really wouldn't be losing that much IMHO with the bigger unit.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    John,

    Can you ground the neutral with the exellech?

    Tony
  • Moe
    Moe Solar Expert Posts: 60 ✭✭
    Re: Advice for a beginner!

    Will the Morningstar SureSine run a small (18 cu ft) Energy Star refrigerator including through the defrost cycle (I have no idea what refrigerators draw)?
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Advice for a beginner!

    Nope ... There is no way the SureSine could handle the compressor turn on.
  • Moe
    Moe Solar Expert Posts: 60 ✭✭
    Re: Advice for a beginner!

    Thank you, SG. I should've asked the same question about the ExelTech 1100 (re the Energy Star refrigerator).

    Here's the answer to the question about neutral-ground bonding from its service manual in the thumbnails below:
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Advice for a beginner!

    from SunElec: http://store.solar-electric.com/exsiwain.html

    This may help, comparing apples to apples. If you have a fridge to start, the morningstar is not your best bet, but for unattended operations, it's got lower idle current.

    And if you decide to go for the exceltech - you may want to consider the 24V version, and remove some voltage loss from your system. With a fridge, you will have to have at least 2 batteries.

    Monringstar 300 $259 (fanless)

    Run 300W

    Max 600W

    Surge 600W (10 min to overheat)

    idle 450mA (in 24hr = 130WH) (not standby)



    exceltech 1100 $525 (w/cooling fan)

    Run 1100

    Max

    Surge 2200 3 sec

    idle 20W x 24h = 480WH Half, if you order it with the X2 option


    let me know if I fouled up the power calcs.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    Mike,

    In my experience, the Morningstar has a idle draw of .055 amps,, .66 watts or ~ 16 watt hours/day.

    Tony

    (Source: Morningstar specs)
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    ..great feedback all.

    I thin I am going to go with the SureSine..I don't need much power for initial lights and rather then running a 12v system I can use the wiring that exists and turn off the pump at the panel and use it when I turn on the generator.

    I am going to order from ebay I think..shipping is a little high but what can you do.

    Next challenge...30 cm of snow tonight...I wish I was in Arizona instead of Nova Scotia...more to come after the weekend.
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    ..snow..great fun.

    Well I ordered the 200w SureSine as it will take care of all my basic needs to start off..in a year I will upgrade if I need to but I want to start small...so thanks for the advice.

    Now, wiring. I have read the installation notes:

    ==================
    Mechanical Specifications
    Dimensions
    213 x 152 x 105 mm ( 8.4 x 6.0 x 4.1 in)
    Weight
    4.5 Kg / 10.0 lbs
    AC Terminals
    Max. Wire Size 4 mm2 / 12 AWG
    DC Terminals

    Max. Wire Size 2.5 to 35 mm2
    14 to 2 AWG
    Remote On/Off Terminals
    Max. Wire Size 0.25 to 1.0 mm2
    24 to 16 AWG
    Enclosure
    IP20 Cast anodized aluminum

    ==============
    I know the wiring is only going to be 5-6 feet from my batteries to the inverter an from the inverter to the panel..could I get recommendations about wire size..I have been attempting to talk to some local for wiring but they are not very knowledgable on 12v wiring..and do I need different types of wire to run from the inverter into the panel since it will be 120 at that point?

    Also, in an earlier post someone posted about size of array vs battery bank size..is there a link that can better explain this?..I have never even thought about that but as suggested I could always take 2 batteries out of the array to compensate and use them elsewhere.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Advice for a beginner!

    The simple answer to all wiring: always use the largest wire size you possibly can. This includes battery inter-connects.
    Wire is wire: AC/DC doesn't make any difference in that respect.
    The battery bank has to be large enough to supply your usage needs, and the PV array has to be able to replace that at a sufficient charging rate over the course of how much sunlight you get in a day. Since only experience can tell you that, start with estimates and be prepared to expand.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!

    The suresine will produce 600 watts of surge at 120vac, or about 5 amps. It will draw, off the 12v battery better than 50 amps! Us a wire size calculator to figure out what is required for 50 amps. (#6 maybe??) I think I have wired mine with #6. At the very least fuse the wire at the battery for the smallest wire between the battery and the inverter. I think that morningstar spec calls for a 50 amp fuse. Fact of the matter you will only be drawing somewhat less than 25 amps for any duration.

    As CC says, in any event use the biggest wire you can,, within reason. Line losses give you nothing,,except room heat you may not need or want. Keeping the inverter as close to the batteries as possible is a good idea, to reduce loss.

    Remember, line loses are inversely proportional to the voltage. Higher voltage, lower loss, lower voltage, higher loss. The wire is rated in amps, regardless (in most cases) of the voltage.

    Tony

    PS Remember, snow is your friend,, it adds reflection on the panels, and in my case adds considerably to my net harvest. That assumes that it isn't snowing!
    T
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Advice for a beginner!

    thx,
    use at least #6 for a voltage drop percentage on that section to be about 1.14%. remember that this gets added to other dc wired sections for the total dc voltage drop percentage that should be kept under 5% overall per nec, but the lower the % the better. if you can use #4 or better that would even be better for you, but may not be necessary. use #12 for the 120vac component from the inverter to the panel.
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    thanks for the info!

    Yes, snow is my friend in one way..for solar production..its NOT so good when I have an unfinished road and I have to park 1/2 km away...but trouncing around in knee deep snow has been great cardio!

    Rain today through Sun..with +12 C expected so it should be gone soon.
  • jacobs
    jacobs Solar Expert Posts: 72 ✭✭
    Re: Advice for a beginner!
    BTW propane refrigerators aren't very efficient and they burn a lot of propane. Getting rid of ours saved a lot on gas, and it doesn't take much electric to run our modern 16 cu.ft. 'frige: 240 watts running (cycles about 1/3 of the time) and a nasty 500 watts when it goes into defrost mode, but that doesn't last long either.

    Propane refrigerators are typically very inefficient, however during the heating season, your refrigerator is helping to heat your home. Bottom line, free refrigeration during the winter if you heat your house with propane.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Advice for a beginner!
    jacobs wrote: »
    Propane refrigerators are typically very inefficient, however during the heating season, your refrigerator is helping to heat your home. Bottom line, free refrigeration during the winter if you heat your house with propane.


    This idea is sort of right,,,,but there are practical limitations.

    Any time you "do work" with electricity (or propane) you generate waste heat. If you use a Propane fridge, and have the flue properly vented outside, the net heat into the building is far less efficient than burning the same amount of fuel in an efficient furnace or space heater for example.

    The same can be said of ovens and stoves. Cooking a roast in the oven contributes significantly to the heating load of the kitchen. Even using a compressor fridge generates "waste" heat 12 months a year,,, during the heating season, that heat is used to reduced the heating load in the house.

    Light bulbs are another one. I had one guy suggest to me that using cfl's was stupid because the kwhs saved by the cfl bulbs had to be replaced from another source. Very true, but the reality is that there are way more efficient ways to heat your space than with light bulbs! (or fridges or water heaters or what have you)

    The reality is to use all our energy as wisely as we can. Keeping heat in when we want it in, and getting it out when we want it out. For example, I have vent louvers behind my fridge with a t-stat controlled fan. In the summer time the fan vents the heat off the condenser out the building. In the winter, it vents the heat into the room. I try to capture as much of the heat from the flue in the winter by using a steel vent pipe and letting it radiate off before exiting the building. In the summer I insulate the flue.

    As for the fundamental efficiency of propane fridges, I contend that if you insulate the cabinet, put a fan on the coils, and fill them properly, they can be pretty darn efficient. As I have said before, we use 1 gallon of propane per week +- for cooking, water heat and fridge. Having said that, if I had to do it over, I would consider a good conventional fridge to run off the solar and cut the need for propane by that much more.

    Tony

    PS. It would be an interesting test, (that I'm sure someone has done) to compare, on a cu.ft./cu.ft basis to compare the btu requirements of a good compressor fridge and a good propane fridge on a annual fuel efficiency basis. I know that my dometics use ~1500 btu/hour, but the duty cycle is under 50% in the summer, and way less in the winter.
  • jacobs
    jacobs Solar Expert Posts: 72 ✭✭
    Re: Advice for a beginner!
    icarus wrote: »
    If you use a Propane fridge, and have the flue properly vented outside, the net heat into the building is far less efficient than burning the same amount of fuel in an efficient furnace or space heater for example.

    Interesting....I've probably seen close to a hundred gas refrigerators of all makes and sizes, new and old, (including a huge 1957 double door Servel) installed and never seen any provisions for outside venting on any of them. Since they weren't vented outside that means 99%+ efficiency or like I said before "free refrigeration" in the winter.
  • System2
    System2 Posts: 6,290 admin
    Re: Advice for a beginner!

    ..hey.

    OK, I am getting close now..thanks for all the advice!

    I have a Morningstar ProStar ( http://www.morningstarcorp.com/en/pro-star )..for a charge controller..I had originally thought this would not be enough but its rated for amps ( 30A ) and I think I might be able to use it for this system..one thing I am confused by is 'No need to derate...use up to full "nameplate" ratings'...

    Does this mean I can combine all of the panels and run them into the charge controller in a series and add up the amps and as long as they are below 30 I am fine?

    Seems the more I get into this the less I know!!