Old solar house with Walmart and "other" batteries..

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CBear42
CBear42 Solar Expert Posts: 28
Hi all -

I purchased an off-grid home two years ago. I haven't been able to live there because the battery bank was discovered to be a disaster after I moved in. They had used a hodge-podge of Walmart and other batteries, deep-discharged them to 0% (because 'that's what you're supposed to do"), let them dry out for a year while they sold the house, etc. They didn't know where the charge controller was and the inverter is an antique. They burned through multiple generators every year. There is an operating solar panel bank of 6 80w panels that seem to be the only thing worth salvaging.

All of this is my own fault. I bought stupidly without educating myself. Lesson learned.

I have calculated my potential electric use (with a little growth room allowed) at approximately 200kwh per month. Refrigerator, on-demand hot water and stove/oven are all propane.

Trying to size my battery bank is the biggest headache so far. From what I have read, I want 12 volt 105 AmpHour AGM lead acid batteries, a Xantrex 2500 Pure Sine Power Inverter, a 3 stage 40 amp Charge Controller, and a good monitoring tool. I need to have the batteries accessible - the house is in very northern New York state - so cold is an issue. Therefore, sealed AGM batteries were recommended to me. I realize that I am probably under-paneled, but it may need to be that way for a while...(I'm working in Europe to make enough to get this puppy into a liveable state!).

Basically, everything goes except the 6 panels that I currently have.

Two questions:
1. How many batteries do I need at a minimum to get myself going? (I am buying a new Generac GP7500 Electric Start Portable Generator as backup - but would prefer not to burn it out like my predecessors did.)

2. Can I add other panels to the existing 80w panels without damage to the existing panels. Or do I need to replace them all at the same time?

I am sure I've forgotten something here .. please let me know if you need any other info.

Thanks very much for your assistance in advance!

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    Welcome to the forum.

    Ah, where to start? Tossing everything probably.

    Since you already understand that a system design is based on loads, let's look at the loads. 200 kW hours per month is nearly 7 per day, and that's quite a bit for off-grid. Your existing 480 Watt array might manage 1 kW hour AC per day if you're lucky. That's pretty far from the target.

    Now, ignore all the equipment choices you have listed in your post. They're all wrong. To start with, AGM's are expensive per Watt hour compared to flooded and are unforgiving of mistakes. Mistakes are easily made, especially when first starting out. Cold is not really an issue: charged batteries will not freeze, and the object is to keep them charged. Piling up twelve batteries in parallel is a disaster; it would be impossible to keep the current flow even through all.

    The first thing you do is select a system Voltage that will meet your needs for stored power. An explanation of the ramifications here: http://forum.solar-electric.com/showthread.php?15989-Battery-System-Voltages-and-equivalent-power
    For 7 kW hours per day you're going to need a lot of stored power: 7000 AC Watt hours is about 8200 DC. On 12 Volts that's 686 Amp hours, or a minimum 1372 Amp hour battery bank which is very large for 12 Volt. 24 Volts is a better choice at 1/2 the capacity, and 48 Volts even better as you could have the 686 Amp hour total capacity and only discharge to 25%. That gives you an "extra day" of stored capacity.

    What you'd need to recharge that battery bank is about 4240 Watts of array. That's like ten times what you've got. Can the old panels be used with the new system? That would depend largely on the actual specs of the old panels (Vmp, Imp, Voc, Isc). Most likely you'd be better off flogging them on E-bay and starting fresh.

    After looking at all that you might want to revisit the load size. The key to a successful off-grid system is to really minimize the loads, because the power comes at a pretty steep price. If grid is available, look in to it. It can be your friend.

    My off-grid consumption, btw, is less than half your proposed loads and that runs everything including the microwave. One of the best things you can purchase is a Kill-A-Watt meter (or similar). Measure the real loads of what you want to use if you can. Some things (240 VAC or hard-wired) you'll still have to estimate.

    Sorry for the terrible shock, but better you find out now than after you spend a lot of money buying stuff that won't supply your needs, eh?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,530 admin
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    Re: Old solar house with Walmart and "other" batteries..

    Welcome to the forum CB.

    First, do not spend anymore money until you have nailed down your needs (other than cleaning up the mess and making it safe).
    CBear42 wrote: »
    Hi all -

    I purchased an off-grid home two years ago. I haven't been able to live there because the battery bank was discovered to be a disaster after I moved in. They had used a hodge-podge of Walmart and other batteries, deep-discharged them to 0% (because 'that's what you're supposed to do"), let them dry out for a year while they sold the house, etc. They didn't know where the charge controller was and the inverter is an antique. They burned through multiple generators every year. There is an operating solar panel bank of 6 80w panels that seem to be the only thing worth salvaging.

    Yea, there is not much left to salvage... Even the current 480 watts of solar array is, probably, not worth salvaging (at best, perhaps you can add it to your system with a decent controller, but I would not go out of my way to do that just yet).
    All of this is my own fault. I bought stupidly without educating myself. Lesson learned.

    Been there, done that. :roll:
    I have calculated my potential electric use (with a little growth room allowed) at approximately 200kwh per month. Refrigerator, on-demand hot water and stove/oven are all propane.

    A 200 kWH per month system is fairly large for an off grid home (although, with today's prices, it has never been more affordable). I would suggest seeing if you can adjust your needs (i.e., conservation, new energy star appliances, insulation, etc.) towards 100 kWH per month (at least for a starting point). You are in an area that does not get large amounts of sun (especially in winter), so keeping energy use to a minimum is going to save you lots of money.

    Note, energy usage is a highly personal choice--If you need more energy, more than happy to help the best we can.
    Trying to size my battery bank is the biggest headache so far. From what I have read, I want 12 volt 105 AmpHour AGM lead acid batteries,

    The "ideal" lead acid battery is AGM--But they tend to cost 2x as much and may not last as long as other types of lead acid batteries.

    In any case, I highly recommend that you get large AH capacity batteries (or cells) so that you do not need to parallel strings of batteries (or two to three parallel strings maximum). Anyway, more on battery bank design later.

    A couple of Battery FAQs:

    Deep Cycle Battery FAQ
    www.batteryfaq.org
    a Xantrex 2500 Pure Sine Power Inverter, a 3 stage 40 amp Charge Controller, and a good monitoring tool. I need to have the batteries accessible - the house is in very northern New York state - so cold is an issue. Therefore, sealed AGM batteries were recommended to me. I realize that I am probably under-paneled, but it may need to be that way for a while...(I'm working in Europe to make enough to get this puppy into a liveable state!).

    Instead of picking hardware, lets look at a design from the bottom up. Say you need 200 kWH per month, fixed array near Massena NY, and some basic rules of thumb for initial design (deratings, flooded cell battery bank, AC inverter, charge during day, power usage at night--i.e., typical worst case assumptions).

    For a battery bank, 200 kWH per month (assume 48 volt battery bank), 1-3 days of no sun (use 2 days here), 50% maximum planned discharge (longer battery life), 85% efficient inverter, we get:
    • 200,000 WH * 1/30 days per month * 1/48 volt battery bank * 2 days no sun * 1/0.50 max discharge * 1/0.85 inverter eff = 654 AH @ 48 volt battery bank

    For batteries, perhaps 16x Trojan L16RE-B 370 AH Deep Cycle Battery (~$5,600 plus shipping and handling and taxes) or 2x Crown Industrial Battery - 24 Volts, 745 Amp-hours (~$7,000 forklift type)

    Inverter wise, you need to look at your peak (starting) loads and average loads... With a ~600 AH 48 volt battery bank, you are looking at a practical maximum of 6kW (6,000 watts) of inverter. Note, there are many Inverter/Chargers out there too--The inverter/chargers tend to work very nicely with genset (are usually power factor corrected--again more later as we discuss). A Xantrex (Schneider) or Magnum 48 VDC 4kW to 6kW True Sine Wave Inverter/Charger will run around $2,200 to $3,000 plus.

    Solar array sizing... Massena NY, using PV Watts with 0.52 system derating, fixed 1kWatt array tilted to latitude (probably near vertical in winter if you have snow):
    "Station Identification"
    "City:","Massena"
    "State:","New_York"
    "Lat (deg N):", 44.93
    "Long (deg W):", 74.85
    "Elev (m): ", 63
    "PV System Specifications"
    "DC Rating:"," 1.0 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.5 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 44.9"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:","14.5 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 3.13, 53, 7.69
    2, 4.28, 64, 9.28
    3, 4.97, 81, 11.75
    4, 5.12, 76, 11.02
    5, 5.02, 74, 10.73
    6, 5.55, 76, 11.02
    7, 5.55, 78, 11.31
    8, 5.23, 73, 10.59
    9, 4.44, 63, 9.13
    10, 3.67, 55, 7.98
    11, 2.44, 36, 5.22
    12, 2.32, 37, 5.37
    "Year", 4.31, 766, 111.07

    My suggested starting point is assume that 3 months of the year, you will need generator backup, the 4th lowest month for your area is October at 3.67 Hours of Sun per day or ~55 kWH per month per 1kW of solar panels. For 200 kWH per month:
    • 200 kWH per month * 1/55 kWH per month per 1kW of panels = 3.636 kW (3636 Watts) or solar array for 9 months of year without generator use

    Of course, you can pick different numbers for your needs (perhaps you don't use 200kWH/month in winter, or don't need 270 kWH per month in summer--your choice).

    A 3,636 Watt array will output, on average, a maximum of:
    • 3,636 Watts * 0.77 panel+solar charger derating * 1/59 volts batt charging = ~47 Amps

    There are a many 60+ amp solar charge controllers, look at Midnite (Classic), MorningStar (TS MPPT family), Xantrex, and Outback (FM80)... Note, I am suggesting a 48 volt battery bank and MPPT type charge controllers. Not cheap ($500-$600 or so), but for your requested size system, usually the best functional choice overall.
    Two questions:
    1. How many batteries do I need at a minimum to get myself going? (I am buying a new Generac GP7500 Electric Start Portable Generator as backup - but would prefer not to burn it out like my predecessors did.)

    Before purchasing a genest, do some more research (and size your PV system)... 7.5kW is not a bad size (oversizing genset will cost you a lot in fuel), but there are only a few 1,800 RPM generators these days that are even warranted for off-grid home use (and many of the newer gensets do not seem to last long--Generac has some good and some not so good units--from what I have read). Have you picked a fuel (propane, diesel, gasoline?). Also, Generator Fires are not uncommon--Recommend keeping generator and fuel supply separate from home/battery/solar array shed. Battery bank safety is important too (appropriate sized wiring/fuses or breakers where needed, etc.).

    It is difficult to recommend a minimum bank and then adding batteries later (I don't like paralleling batteries if you do not have too, and adding new batteries to an old battery bank can cause charging/overall battery life issues). If you don't know what you want... Get "cheap" flooded cell lead acid batteries that will last you 3-6 years, then replace them with a new set (frequently we call these training batteries because people do frequently kill their first battery set (over discharging, improper watering, over charging, family member left pump/hair drier on and left home, etc.).
    2. Can I add other panels to the existing 80w panels without damage to the existing panels. Or do I need to replace them all at the same time?

    You can add more panels--but frequently the Mix and Matching of old+new panels is difficult. The "modern" 200+ watt panels do not usually "mix" well with older/smaller panels (unless you use a second charge controllers for the old panels and parallel with new charge controller to battery bank). In your case, you are saving about $480 in panels, adding another charge controller+wiring... May not be worth it.

    Battery Monitors (Victron, another good brand), I highly recommend (not perfect, but they do a good job of letting you know what is happening with battery bank).
    I am sure I've forgotten something here .. please let me know if you need any other info.

    Inverter FAQs:

    All About Inverters
    Choosing an inverter for water pumping

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..
    CBear42 wrote: »
    I have calculated my potential electric use (with a little growth room allowed) at approximately 200kwh per month. Refrigerator, on-demand hot water and stove/oven are all propane.

    As Cariboocoot mentioned, that's pretty high kwh for an off grid house. You really need to do a precision kwh audit. One item you mentioned is a red flag item.... your propane stove. Does it have a glow bar? If so it will be cheaper to scrap/sell the stove and get a non glowbar stove than to buy the extra electric production and storage capacity you need for the glowbar.

    I'm sure that a good kwh audit (that you can do with a killawatt meter) will pay for itself in the savings on your electric system.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • BB.
    BB. Super Moderators, Administrators Posts: 33,530 admin
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    Re: Old solar house with Walmart and "other" batteries..

    Kill-a-Watt meter for 120 VAC 15 amp appliances (or equivalent).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CBear42
    CBear42 Solar Expert Posts: 28
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    Re: Old solar house with Walmart and "other" batteries..

    I have revisited my load analysis and taken out any "fluff". Because I am not currently at the house, the KilloWatt isn't too practical at this point. When I WAS there, I made note of the wattages of all my equipment, etc. so what I have (as far as they have listed) is accurate. By removing most creature comforts, I can get it down to 124KwH per month. A laptop and printer are fixed - need them for work.

    >If grid is available, look in to it. It can be your friend.

    Grid tie is not an option. NYSEG ran lines to the house in the 1960's but after an ice storm - they decided to cut all the poles down. Now they want almost $250,000 to run them back again. Think of the off-grid system I could buy for THAT! :-)

    I'm wondering if my calculations are wrong:

    I am measuring watts * hours/usage per day * quantity / 1000 = x KwH/month.

    I don't use a microwave, have taken out all "extra" kitchen appliances - and have only this left:

    Lights (4 60w bulbs used for 6 hours a day)
    Hair Dryer (used less than 10 minutes per day)
    Phone Base & Extensions .3 watt used 24 hours a day
    TV - Energy-Star [399 watts * 1 hour a day)
    Laptop - used 12 hours a day, 65 watts)
    Printer, Laser - used less than 30 minutes a day)
    Vacuum Cleaner (700 watts used 3x a week for 30 minutes
    Toaster (1200 used daily for 5 minutes or less)

    I'm not sure what else I can cut out!

    Thanks for your input - I so truly and really appreciate it!

    CBear
  • CBear42
    CBear42 Solar Expert Posts: 28
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    Re: Old solar house with Walmart and "other" batteries..

    OK - what the heck is a "glow bar"? And how do I know if I have it?

    Thanks in advance for all this wonderful advice.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,530 admin
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    Re: Old solar house with Walmart and "other" batteries..
    CBear42 wrote: »
    1,440 WH = Lights (4 60w bulbs used for 6 hours a day)
    300 WH = 1,800w * 1/6th hour Hair Dryer (used less than 10 minutes per day)
    7.2 WH = Phone Base & Extensions .3 watt used 24 hours a day
    399 WH = TV - Energy-Star [399 watts * 1 hour a day)
    780 WH = Laptop - used 12 hours a day, 65 watts)
    150 WH = ~300 watts * 1/2 hour per day Printer, Laser - used less than 30 minutes a day)
    150 WH = 700 W*1/4 hours per day Vacuum Cleaner (700 watts used 3x a week for 30 minutes
    100 WH = Toaster (1200 used daily for 5 minutes or less)
    ===========================
    3.32 kWH per day average (if I did the addition right)

    No refrigerator/well pump/sump pump/washing machine?

    The lighting is your largest load--Look to LED and CFL for general purpose lighting. You may prefer a Halogen desk lamp (like 25 watt)--but keep those to a minimum (possibly use motion detector--Yes, not a fan of motion detectors for lighting--on any lights you tend to leave on when you walk away from desk).

    TV--You should be able to find something less than 100 watts (or even use your laptop--I got a nice Digital Receiver for less than $90 that has USB for computer use), but it is not a "killer" at 1 hour per day.

    Toaster and hair drier--Those will set a "floor" on the size of your battery bank and inverter.

    The laptop--You can get down towards 20-30 watts pretty easily--But if you need the large screen, high processing power, it is what it is.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    "Glow bar": source of ignition for some, but not all, gas ovens/dryers.

    Watt hours is pretty much what it sounds like: Watts * hours used. For instance your light bulbs:

    Four 60 Watt bulbs is 240 Watts. Times 6 hours per day is 1440 Watt hours per day.
    Change to CFL's and it becomes four 13 Watt (some draw more due to poor power factor) bulbs for 52 Watts * 6 hours = 312 Watt hours per day.

    1500 Watt hair dryer * 10 minutes (1/6th of an hour) = 250 Watt hours, but a need for a big inverter to handle the maximum Wattage of all the loads (even if only for 10 minutes). The same for the toaster.

    One of the problems with not measuring the actual usage with a meter is that the nameplate ratings are often far off the actual usage numbers. Sometimes they are less, sometimes they are more. Example: "1.5 Amps @ 120 Volts" may be 180 Watts, but that can be peak power and really the thing uses 75 Watts (actual numbers pulled from a monitor here, btw). Some things, like the TV, can be adjusted to use less: turn down the screen brightness as low as you can stand it and watch the Amps drop.

    Another off-grid power saver is load management. Once the batteries are recharged, the panels will have nothing to do. Turn what loads you can on then and they will make use of panel power that otherwise would go unharvested.

    From your equipment list, your power use may not be as high as you think. We run an electric refrigerator (1200 Watt hours per day - the major power consumer), plus two water pumps (850+ Watts in for about 6 minutes, 1200+ Watts out for about 30 seconds) and have the full office/satellite connection/phone (VOIP) set-up.

    If I could afford it I would increase my power supply by about 1000 Watts of panel and another 232 Amp hours of battery. I'd still have the generator though; you'd be amazed at the lean sun times that can see you through cheaply. It has run every day for six days now in this sunny (HA!) month of June.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,530 admin
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    Re: Old solar house with Walmart and "other" batteries..

    With modern gas (natural/propane) appliances, they frequently use a "glow bar" (think red hot metal wire--but really a ceramic coated with a conductive material) that takes around 300-500 watts to glow red hot and light the gas. Frequently used in Ovens and Clothes Driers. Some turn on 100% of the time the gas is running (my oven), others only turn on when lighting flame (my drier).

    There are spark type ignition--but, I have read here before that people did not like the "sparking" noise in Ovens/Driers when lighting the flame.

    Peerless seems to be pretty popular for off grid stoves (or only game in town?):

    www.premierrange.com

    Note, many appliance and clock/radios/etc. run their timers off of the 60 Hz AC power... AC inverters do not hold the 60 Hz frequency accurate enough for clocks to keep time--So either avoid digital AC clocks, or learn to ignore the date/time display.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    in general you would be surprised at what really is drawn and to gauge this over time by nameplate is a wild guess at best. that guess would most likely be high unless you underestimate the times used. you really don't know where you stand load wise and what the best courses of action to be at this point to base the implementation of a pv installation. to say you need something is a given and you will want and need a generator even after you determine the proper loads at your home for there are times the sun just doesn't shine like we would want it to. i say get a properly sized quality generator of which the most efficient are the inverter generators and determine your actual loads and watthour results. a meter such as a killawatt is a necessity and we realize you can't do it right now while working elsewhere, but you will need to do this sometime. the meters are between $20 and $30 usually and are even available in some places like home depot, lowes, and even radio shack not to mention by our host northern arizona wind and sun.
  • Photowhit
    Photowhit Solar Expert Posts: 6,005 ✭✭✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    As Coot and others here have eluded to, the energy actually used will differ from label rating.

    I'm working on taking a modular home of grid, and 1st conversion is Compact florescents in all the fixtures, other than the outside light which I tend to leave on 24/7 which has a 4 watt LED, which is plenty to see whats going on on the porch, even from the road, and yet I may change this to some quality stand alone solar lights, when i do go off grid. Learning that you need only 1 or 2 lights on at any one time is part of the off grid thing (...are there others involved, wife, kids)

    I've had long hair, before I became folicly challenged and have very rarely used a hair drier. I like toast, and understand your desire, but I don't use a toaster anymore mostly from my past 10 years living off grid, I'll nuke oatmeal for breakfast, Microwaves aren't too bad, while they use a lot of energy, it's for a very short time.

    Your laptop may have a 65 watt power supply, but will typically use a fraction of that 35-40 watts is likely.

    As it appears your off grid to stay, I'd shoot a battery bank that will sustain you for a couple days and a quality generator and charger/inverter at first, Your loads look like a big 24v or small 48v system. You panels 8 of the same size will be useful, and buying 8 of the same appears to be the one smart thing the previous owners did, as likely they are 12V nominal panels and can help maintain the batteries, when your off working. They won't do much toward charging the batteries toward useful loads, but might make taking a week or 2 away more comfortable. I would just use them with a cheap PWM charge controller as likely they will not match your future panels.

    As you haven't lived off grid in the past, I might not buy any panels for a while, rather monitor your energy use for a year, and see where your needs fall. You'll learn a bunch as you live within an energy budget.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • CBear42
    CBear42 Solar Expert Posts: 28
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    Re: Old solar house with Walmart and "other" batteries..

    >Learning that you need only 1 or 2 lights on at any one time is part of the off grid thing (...are there others involved, wife, kids)

    Just me. Fortunately!

    >I've had long hair, before I became folicly challenged and have very rarely used a hair drier.

    Well, I'm a girl and still not follically "challenged"...so, the hair dryer is pretty much a necessity.. ;-)

    >Your laptop may have a 65 watt power supply, but will typically use a fraction of that 35-40 watts is likely.

    This is good to know...also, I may just replace it with the most efficient laptop I can find before I go back.

    >You panels 8 of the same size will be useful, and buying 8 of the same appears to be the one smart thing the previous owners did,

    Actually- no. There are six panels of 80 watts each. They are definitely 12V though. (Comment on smart previous owners shall go unnoted.)

    >As you haven't lived off grid in the past, I might not buy any panels for a while, rather monitor your energy use for a year, and see where your needs fall. You'll learn a bunch as you live within an energy budget.[/QUOTE]

    I already have! I lived up there for 5 months until the system finally collapsed, generator died - and I was forced to leave and find work. But, I DID learn a lot and know that I can live on far less than I would have thought possible (hair dryers notwithstanding... :-). I don't mind roughing it a bit - and think I'll have to...but it's a great - albeit steep - learning curve.

    After doing some re-calc, I think my monthlyl KwH usage is more likely going to be in the 120 range. (Know that's not as accurate as it should/could be...but, the house is 7,000 miles away at the moment..)

    Thanks everyone for your quick, amazing and comprehensive, and thoughtful replies. You all rock!
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..
    BB. wrote: »
    Note, many appliance and clock/radios/etc. run their timers off of the 60 Hz AC power... AC inverters do not hold the 60 Hz frequency accurate enough for clocks to keep time--So either avoid digital AC clocks, or learn to ignore the date/time display.

    -Bill

    I disagree on this point - the ones I have hold a solid 60 Hz when on battery, only fluctuating to match the incoming frequency when operating from the grid.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..
    techntrek wrote: »
    I disagree on this point - the ones I have hold a solid 60 Hz when on battery, only fluctuating to match the incoming frequency when operating from the grid.

    But the ones you have aren't exactly standard-issue off-grid inverters, are they? :cool:

    I've never checked the Outback for long-term frequency stability. Running it in search mode would sort of throw that all in the hopper anyway. :D
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..
    BB. wrote: »
    Peerless seems to be pretty popular for off grid stoves (or only game in town?):
    www.premierrange.com

    Not the only game in town:
    http://www.uniqueoffgrid.com/en-Ca/Products/Product-Line-up_/Off-Grid-Ranges.html

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    The Unique ranges appear to be spark ignition from a 9 Volt battery.
    The Peerless are standing-pilot.

    Just saying. :D
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    Re: Old solar house with Walmart and "other" batteries..

    9V battery is far superior to the parasitic draw of a 110v igniter... in a PV system. Just need a spare 9v on hand or a book of matches
     
    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
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    Options
    Re: Old solar house with Walmart and "other" batteries..
    But the ones you have aren't exactly standard-issue off-grid inverters, are they? :cool:

    I've never checked the Outback for long-term frequency stability. Running it in search mode would sort of throw that all in the hopper anyway. :D

    Its all the same technology in the inverter - frequency controlled by a quartz crystal to hold a 60 Hz output, just like a digital watch. All of the watches I've had in the last 10-15 years hold time to within a few seconds over a year, hardly a fluctuation that would be noticeable day-to-day.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • Dill
    Dill Solar Expert Posts: 170 ✭✭
    Options
    Re: Old solar house with Walmart and "other" batteries..

    neither my Xantrex ProWatt SW 1000 watt nor the Morningstar Suresine 300W can keep my alarm clock on time!