Noob with questions for the SME's on here. (Subject Matter Experts)

Edward H
Edward H Registered Users Posts: 10
Hello!

My wife and I are moving to our property in northern Ontario this June to start building our little off-grid passive solar, bermed homestead.
You can follow our journey here: http://northerndirtbags.blogspot.ca/

Looking to put together a system for the house, to be put in permanent place before winter. Would like to be able to connect the guts to some panels and batteries while building, a mini power system if you will. So with that in mind I have thought of doing this...

One of these to run the show, it says 48V but can do 24V and even 12V, can't it?

http://dnmsolar.com/product.php?product=136


For panels I'm thinking 6 of these...

http://dnmsolar.com/product.php?product=114

And for batteries, maybe 4 of these for a 24V system. The Surrette S-530's

http://www.rolls-battery.com/pdf/pdf_rolls/s530.pdf?phpMyAdmin=2eda4dec0bd69647b9e3cf0f71e01d23&phpMyAdmin=9dec4a269d70t7a63be7c

Any glaring issues or problems you gentlemen might see and point out would be greatly appreciated. Bad balance between components or anything that's off.

I await the flow of knowledge.

ED...

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    Edward H wrote: »
    Hello!

    My wife and I are moving to our property in northern Ontario this June to start building our little off-grid passive solar, bermed homestead.
    You can follow our journey here: http://northerndirtbags.blogspot.ca/

    Welcome to the forum.
    Looking to put together a system for the house, to be put in permanent place before winter. Would like to be able to connect the guts to some panels and batteries while building, a mini power system if you will. So with that in mind I have thought of doing this...

    One of these to run the show, it says 48V but can do 24V and even 12V, can't it?

    http://dnmsolar.com/product.php?product=136

    No. That is a 48 Volt inverter. It requires a nominal 48 Volt battery bank to function.

    For panels I'm thinking 6 of these...

    http://dnmsolar.com/product.php?product=114

    And for batteries, maybe 4 of these for a 24V system. The Surrette S-530's

    http://www.rolls-battery.com/pdf/pdf_rolls/s530.pdf?phpMyAdmin=2eda4dec0bd69647b9e3cf0f71e01d23&phpMyAdmin=9dec4a269d70t7a63be7c

    Any glaring issues or problems you gentlemen might see and point out would be greatly appreciated. Bad balance between components or anything that's off.

    I await the flow of knowledge.

    ED...

    You're making the #1 mistake: guessing at equipment without knowing what you actually need.

    An off-grid system is based on the daily Watt hour requirements and maximum Watts to be supplied. If you don't have those numbers you have a 2/3 chance of getting it wrong. Pretty bad odds.

    So you start with the power requirements. If you need 'X' Watt hours per day then you can determine the proper system Voltage and battery bank size to use. A short bit about battery Voltage and equivalent power: http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power

    The second thing is that maximum Watts at any one time which will tell you the amount of power the inverter must be able to supply. There's no sense buying a 3.6 kW inverter if all your loads (including surge demands) are under 1kW.

    Once you've got that figured out you look at how to recharge those batteries. That starts with the basic formula of 10% of the Amp hour capacity of the battery bank as the peak charge current:
    Peak Charge Current * nominal system Voltage / 0.77 efficiency for panels & MPPT controller = array size.
    After that you make adjustments to the design until you get it all to work - before you buy anything.

    BTW you left the charge controller out of your major component list. You will also need to plan on things like wiring, over-current protection, mounting hardware, and possible some other accessories depending the basic equipment you select (as in Outback FX inverters need a MATE to program them).
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Marc has it right...avoid the "ready, fire, aim syndrome"! Before you do anything, do a good load estimate. All design (and hardware )considerations. The loads determine the size of the battery, the size of the battery determines the size of the PV. The inverter is more complicate since it may hve to power large peak loads, and smaller continuous loads, so some folks consider two inverters to do different functions,

    A couple of simple rules of off grid power. First, all loads grow with time, second, most people over estimate the solar potential while at the same time underestimating thier loads.

    Also when you do some load calcs consider load shifting, -and time shifting of loads. For example consider pumping water while running the genny for charging, or waiting to pump water in the afternoon when the batteries are near full and you have excess capacity.

    Welcome to the forum, keep in touch, and feel free to ask as many questions as you need. There are many helpful, smart folks here who are all too willing to help. Most have forgotten more about RE than most others know. (don't include me in that however!)

    Keep in touch,

    Tony

    PS as a strting point, and it works pretty well for me in NWO is the following. To determine the actual real world output of a small off grid system, here is my formula: take the name plate rating of the PV, divide in half to account for all cumulative system loses, then multiply that number by 4 to account for the average number of hours of GOOD sun per day, averaged over the course of the year. So for example, 1000 watts of PV will look like this. 1000/2=500*4=2000 WH/day. For the record, my system is 400 watts. We use between 5-800 WH day, and we seldom have to run a genny to charge. In the north, you will gain an advantage of long days in the summer, and the reflection off of snow will make up to some extent for the short days of winter. Dec and Jan are the troublesome months.

    T
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    One way to figure out what you need is to get a couple of gensets...

    A smaller one (like a Honda eu1000i, eu2000i, similar Yamaha inverter-generator) for your smaller loads (some lights, refrigerator, small/efficient water pump, TV, laptop, etc.).

    And a larger one you fire up to run the power/shop tools, well pump to cistern, etc.

    The small genset may cost you just ~1-2 gallons of fuel per day, and the larger one will pull ~1-2 gallons per hour--So you only want to run that when you have larger loads operating.

    Get a Kill-a-Watt type meter for the smaller genset and measure your power usage during a 24 hour period. And design/build a "small offgrid" system to support those loads while building (assuming you are looking at a project that is more than a few months). This gives you your "quiet power" for your smaller loads and the large genset for larger loads (don't even design a solar power system to support large/random use/short term use loads--It is too expensive unless you are sure that it will support your completed home in the next few years).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    Welcome to the forum.



    No. That is a 48 Volt inverter. It requires a nominal 48 Volt battery bank to function.


    You're making the #1 mistake: guessing at equipment without knowing what you actually need.

    An off-grid system is based on the daily Watt hour requirements and maximum Watts to be supplied. If you don't have those numbers you have a 2/3 chance of getting it wrong. Pretty bad odds.

    So you start with the power requirements. If you need 'X' Watt hours per day then you can determine the proper system Voltage and battery bank size to use. A short bit about battery Voltage and equivalent power: http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power

    The second thing is that maximum Watts at any one time which will tell you the amount of power the inverter must be able to supply. There's no sense buying a 3.6 kW inverter if all your loads (including surge demands) are under 1kW.

    Once you've got that figured out you look at how to recharge those batteries. That starts with the basic formula of 10% of the Amp hour capacity of the battery bank as the peak charge current:
    Peak Charge Current * nominal system Voltage / 0.77 efficiency for panels & MPPT controller = array size.
    After that you make adjustments to the design until you get it all to work - before you buy anything.

    BTW you left the charge controller out of your major component list. You will also need to plan on things like wiring, over-current protection, mounting hardware, and possible some other accessories depending the basic equipment you select (as in Outback FX inverters need a MATE to program them).



    I tried to reply between the quotes and messed it all up, TWICE! So just going to past it in at the bottom here.

    That power system was listed by the company with the panels I want to get. I was looking for a 'power system' but I'll be better off putting the bits together myself. 48V is not where I was looking anyway and 3.6kW looked way too overkill to even me. So that helps!

    'Must have' watt hours/day would be about 500-750, so call it 1000. To cover some other needs when available I would say 2000 would be plenty. The 'must have' is to cover 2 Danby 'Simplicity' 7cu. ft. chest freezers run with 2 temperature controllers http://amzn.to/1msuQvt turning one into a fridge. This works quite well from an off-gridder I know.

    So the max draw would be when power is plenty and my wife wants to use a Vitamix, around 1500W as far as I can tell. So I was thinking a 2000W inverter would do. Am I on the right track with this?

    Ok, this part is all 'Greek' to me. With 6 of the 300W panels listed above and 4 of the 6V Surrette S-530's set for 24V, am I on the right track?

    I understand the extra costs for wiring and mounting. What charge controller would better fit the new list here?
    Hope I'm getting closer to understanding this and not just being a pain.

    ED...
  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    I don't know where you live, but here in Ottawa, the public library will lend you a Kill-A-Watt meter. Either pick one up from them, or buy one - the seem to be rather scare in brick and motar stores around here.

    Use the meter to measure everything that you want to run (and think that you'll might want to run). You'll then have a pretty good idea of what your usage will be. Once you've got this firgured out, you can move onto sizing the battery bank, solar panels, charge controller, inverter. Doing it any other way is just asking for trouble. (using this Vitamix, around 1500W as far as I can tell. So I was thinking a 2000W inverter would do. kind of planning won't work)

    Jerry
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Ok, you have decided on the 'bottom floor' number of 1 Kwh per day.... now you have to ask yourself about the eventuality of wanting to expand the system in the future? Why? Because in this field, there is a tendency for loads to grow over time ( Icarus Solar Rule #1). So if there is the faintest possibility, you want to consider it at this time, it will make things a lot easier...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Two "main numbers" we are looking for... Yes, one of them is "peak watts" (all of your base loads + refrigerator/well pump starting, etc.).

    And the starting surge is the most difficult to quantify... Both because it is difficult/more expensive to measure (most "standard" meters simply take a sample once a second) and because different inverters/generators have difficult behaviors when subjected to heavy loads (some will surge the the needed energy, some will brown out a bit, and others will shut down). To a degree, the more you spend ($$$ per Watt) for your inverter, the wider its capabilities will be.

    I am on grid, but if you give a rough list of what you want to run, you can get some suggestions on what inverter models/sizes the others would suggest.

    The other "main number" is Watt*Hours or kWH per day (or Amp*Hours if you are into 24 VDC logging/estimating). Running a 1.5 kW mixer or microwave for a few minutes a day is different than running a 200 Watt computer workstation/server 24 hours per day:

    1,500 Watts * 1/6 hours per day (i.e., 10 minutes) = 250 Watt*Hours per day = 0.25 kWH per day (a 500 Watt solar panel would be more than enough)
    200 watts * 24 hour per day (i.e., computer server) = 4,800 WH = 4.8 kWH per day (enough to run an entire off energy eff grid home)

    While you can design a system to run a blender for 10 minutes per day--In general, it is the average load over 24 hours that define much of the system design. If the system is "large enough" to run your 24 hour loads, it is usually large enough to run your surge loads too.

    Pretty much, you can run on a 300 watt AC inverter (laptop computer, lights, cell phone charger, LED TV, ratio) until you wan to run an AC refrigerator and well pump--Then you are looking at 1,500 watt to 2.5 kW or larger AC inverter.

    Off grid solar power is expensive (very roughly $1-$2+ per kWH or ~10x your utility costs)... Conservation, choice of loads (i.e., pick the most energy efficient fridge/well pump/electronics) is usually going to save you more money than just throwing more money at your off grid power system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Thanks Tony. We will be treating our power as a 'bonus' and not coming to off-grid expecting to run a regular household! Using your formula there with what I have just posted I would have 6x300W: 1800/2=900*4=3600 WH/day. We are on the 49th Parallel in Northeastern Ontario and get a lot of real winter. I expect the possible 'overkill' of panels will be a help in the short winter days where counting 4 hours GOOD light is not going to be happening.
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Thanks Bill, I'll keep this in mind once we get to the property and get rolling.
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Hi Jerry. I'm in Hamilton currently and we are moving to the Cochrane Ontario area. I can get a Kill-a-Watt from the library and it's listed as available in stores. The problem is, as listed in my response to Coot, I don't own the items I'm planning to have/use. The Danby's I have data from a friend who is using what I plan to use. I will see what hard data I can find for a Vitamix. I believe it's 1500-1600 watts but will see what I can dig up.

    Thanks for your input. I was born and raised in Ottawa. Went to Brookfield H.S. way back in the late 70's.
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Yes, sir. That's why in the latest posting I said 1000 but was going with 2000 to cover future 'extras'.
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Note taken, Bill. As listed in my response to Coot...

    'Must have' watt hours/day would be about 500-750, so call it 1000. To cover some other needs when available I would say 2000 would be plenty. The 'must have' is to cover 2 Danby 'Simplicity' 7cu. ft. chest freezers run with 2 temperature controllers http://amzn.to/1msuQvt turning one into a fridge. This works quite well from an off-gridder I know.

    All computer type use is now in an iPad and a Transformer tablet. Our 'main PC' is a little media centre that uses 65 watts and the TV is 120 watts, they will only be used when power is not an issue. We are keeping it simple and plan to stay minimal.

    ED...
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Ed, re the TV, we got a 19" Toshiba with built in DVD player and it only draws 13Amps!


    The limiting factor for the Inverter and 2 fridges, is if both of them turn on simultaneously... it would overload you inverter and shut you down... Odds of it occurring? quite low but it can happen. A full size fridge will draw only a bit more than a small fridgette...and you get a fridge and freezer...

    http://forum.solar-electric.com/showthread.php?12272-Just-how-bad-a-small-frige-is&highlight=fridge
    http://forum.solar-electric.com/showthread.php?22229-Fridge-freezer-power-use-vs-2-chest-freezers&highlight=bad+small+fridge
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    You sound like you have a real epic journey ahead of you. You have approximately two choices, get a professionally designed and installed system; OR; spend about 3 weeks full time reading and learning to DIY. The problem is you are going to have to live with the system, maintain it, expand it etc, so from my point of view it may as well be the latter approach. After all if you are handy enough to build a house, you should do ok. A few basic electrical concepts, some common sense, and most of all a healthy respect for electricity. "Just becasue its of grid doesnt mean it wont kill you or burn your house down".

    Edward H wrote: »
    'Must have' watt hours/day would be about 500-750, so call it 1000. To cover some other needs when available I would say 2000 would be plenty.

    This sounds a bit too squishy to me. Installed solar capacity is pricy, and changes are difficult, and, you are at the planning stage of a whole new house and life. Now is the time to plan. Figure out what you need, spend the time, do it right.
    The thing about homesteading is that you take your self with you. If you are currently using 60kWh/day, that says something about how you live and what sort of things you expect. So go round your present place with the killawatt, leave it running on each outlet for a day or a week. Pore over your power bills, until you understand where it all goes.

    Then make up a spreadsheet/table of the items you want to run off grid. Youll be moving some items to propane, and probably using some new technolgoys, like LED lighting, efficient appliances. We can help with the specfics when you have questions.
    The 'must have' is to cover 2 Danby 'Simplicity' 7cu. ft. chest freezers run with 2 temperature controllers http://amzn.to/1msuQvt turning one into a fridge. This works quite well from an off-gridder I know.

    A fridge and freezer as a general rule of thumb puts you into the 3kWh/day territory. I have a sample 3kWh/day load budget lying around here somewhere if its any use, as a place to start.
    All computer type use is now in an iPad and a Transformer tablet. Our 'main PC' is a little media centre that uses 65 watts and the TV is 120 watts, they will only be used when power is not an issue. We are keeping it simple and plan to stay minimal.

    ED...

    Simple is good. Then, for poor weather youll need backup (or aggresive conservation strategys), and as well you can find uses for your surplus power, on gridders heads will struggle with that one :)

    Obviously with a new house build you get a chance to do interesting stuff like passive solar themal design, passive cellar/pantry cooling, lots of insulation, solid fuel mass heaters etc etc.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • Rybren
    Rybren Solar Expert Posts: 351 ✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    Edward H wrote: »
    we are moving to the Cochrane Ontario area.

    Why?????? :D

    I lived in various places throughout Northern Ontario from about '76 to '90 and loved it. Now that I'm much closer to 60 than 50, I prefer a milder and mellower climate (not that Ottawa is that much better, but winter is usually 4 or 5 weeks shorter).

    The guys here really know their stuff. If you follow their advice, you'll make out okay.
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    zoneblue wrote: »
    You sound like you have a real epic journey ahead of you. You have approximately two choices, get a professionally designed and installed system; OR; spend about 3 weeks full time reading and learning to DIY.

    It will take a lot more than 3 weeks to figure it all out.

    Edward H, how will your panels be mounted (ground, pole, roof)? How far from your batteries and electronics? Will your batteries and electronics be in your house?

    In my opinion, a good place to start learning about how the system goes together is over at Midnite solar. Study their ePanels and the ePanel wiring diagrams. The ePanels are designed for particular inverters... you specify the inverter (Outback, Magnum, Xantrex, etc) and they have a panel with all the correct circuit breakers, bus bars, shunts, lightning arrestors, etc.

    Even if you don't use an ePanel, its a good education to read about them.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    vtmaps wrote: »
    It will take a lot more than 3 weeks to figure it all out.

    Edward H, how will your panels be mounted (ground, pole, roof)? How far from your batteries and electronics? Will your batteries and electronics be in your house?

    In my opinion, a good place to start learning about how the system goes together is over at Midnite solar. Study their ePanels and the ePanel wiring diagrams. The ePanels are designed for particular inverters... you specify the inverter (Outback, Magnum, Xantrex, etc) and they have a panel with all the correct circuit breakers, bus bars, shunts, lightning arrestors, etc.

    Even if you don't use an ePanel, its a good education to read about them.

    --vtMaps

    Using MidNite equipment isn't learning about solar, it's taking the short-cut to success! :D

    You want to learn you buy the no-name Chinese crud equipment and wire it up and watch the smoke come out while wondering what you did wrong. You get important lessons that way. For example you learn not to buy the no-name Chinese crud equipment. ;)

    Honestly, the pre-wired panels are great for installing but you may not learn all the why's and wherefor's.
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    vtmaps wrote: »
    It will take a lot more than 3 weeks to figure it all out.

    Edward H, how will your panels be mounted (ground, pole, roof)? How far from your batteries and electronics? Will your batteries and electronics be in your house?

    In my opinion, a good place to start learning about how the system goes together is over at Midnite solar. Study their ePanels and the ePanel wiring diagrams. The ePanels are designed for particular inverters... you specify the inverter (Outback, Magnum, Xantrex, etc) and they have a panel with all the correct circuit breakers, bus bars, shunts, lightning arrestors, etc.

    Even if you don't use an ePanel, its a good education to read about them.

    --vtMaps

    Looking at a pole mount and placing within a 40' run of the utility room. If it ends up as a 'roof' mount then half that. I will certainly check out the Midnite Solar site, ePanels sound like what I was looking for. After the info from previous responses and checking expected loads I can say it's a 2kWh/day load I will be building. Talking with my wife and she is good with nixing the Vitamix (don't own one yet anyway) so that will make the Inverter necessary less beefy.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Any Refrigerator or computers (and/or other items that may have low average power use but are turned on/used many hours per day)?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    BB. wrote: »
    Any Refrigerator or computers (and/or other items that may have low average power use but are turned on/used many hours per day)?

    -Bill

    I replied to this but didn't have you quoted. Here it is again for you.

    'Must have' watt hours/day would be about 500-750, so call it 1000. To cover some other needs when available I would say 2000 would be plenty. The 'must have' is to cover 2 Danby 'Simplicity' 7cu. ft. chest freezers run with 2 temperature controllers http://amzn.to/1msuQvt turning one into a fridge. This works quite well from an off-gridder I know.

    All computer type use is now in an iPad and a Transformer tablet. Our 'main PC' is a little media centre that uses 65 watts and the TV is 120 watts, they will only be used when power is not an issue. We are keeping it simple and plan to stay minimal.
  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)

    Coot, *you* are a real classic. I reckon we'll keep you around, your just too much fun.
    Using MidNite equipment isn't learning about solar, it's taking the short-cut to success! :D

    You want to learn you buy the no-name Chinese crud equipment and wire it up and watch the smoke come out while wondering what you did wrong. You get important lessons that way. For example you learn not to buy the no-name Chinese crud equipment. ;)
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    Edward H wrote: »
    I replied to this but didn't have you quoted. Here it is again for you.

    'Must have' watt hours/day would be about 500-750, so call it 1000. To cover some other needs when available I would say 2000 would be plenty. The 'must have' is to cover 2 Danby 'Simplicity' 7cu. ft. chest freezers run with 2 temperature controllers http://amzn.to/1msuQvt turning one into a fridge. This works quite well from an off-gridder I know.

    All computer type use is now in an iPad and a Transformer tablet. Our 'main PC' is a little media centre that uses 65 watts and the TV is 120 watts, they will only be used when power is not an issue. We are keeping it simple and plan to stay minimal.

    On the Energy Star site I looked up a Danby 7 cu ft freezer and it listed it at 222 kWh a year or 0.606 kWh a day on the 2001 test suite. 2 of them will at least draw 1.2 kWh a day. That is if conditions are ideal.

    http://www.energystar.gov/productfinder/product/certified-residential-freezers/details/2163686
  • Edward H
    Edward H Registered Users Posts: 10
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    solar_dave wrote: »
    On the Energy Star site I looked up a Danby 7 cu ft freezer and it listed it at 222 kWh a year or 0.606 kWh a day on the 2001 test suite. 2 of them will at least draw 1.2 kWh a day. That is if conditions are ideal.

    http://www.energystar.gov/productfinder/product/certified-residential-freezers/details/2163686


    As I said if you use the temperature controllers you can save tons. Temperature controllers http://amzn.to/1msuQvt - An acquaintance is doing it now. "My meter did show max amps at 4.75 and max watts at 552 but I watched the thing when it kicked in a few times and never saw it hit those levels."

    Check out his blog here - http://muddome.wordpress.com/

    I'm fine with my estimates for need. Looks like a 2000W Inverter should do the trick too.
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Re: Noob with questions for the SME's on here. (Subject Matter Experts)
    Edward H wrote: »
    As I said if you use the temperature controllers you can save tons. Temperature controllers http://amzn.to/1msuQvt - An acquaintance is doing it now. "My meter did show max amps at 4.75 and max watts at 552 but I watched the thing when it kicked in a few times and never saw it hit those levels."

    Check out his blog here - http://muddome.wordpress.com/

    I'm fine with my estimates for need. Looks like a 2000W Inverter should do the trick too.

    There is no magic in operating (start/stopping) a compressor via a different controller, The amount of energy to chill the box remains the same, it is whatever the delta to the exterior temp plus the losses from opening, heat transfer efficiency ...