I want to get into solar where do i begin?

drops101drops101 Posts: 4Registered Users
ok so to start off i kind of aware on how they work and the uses for them.

i am a electrician so wiring and soldering come with expierence

i have small solar panels but the dont have much watts or juice to do anything i have been able to convince the wife to let me buy 100 watt solar panels once a month or should i buy the 200 and wait for every two months? but i dont know who to buy from /

i also read somewhere to not mix solar panels up and afraid of buying them once a month and having mixed panels 

thank you so much for your help i appreciate it

Comments

  • petertearaipetertearai Posts: 301Solar Expert ✭✭✭
    good advice in thss forum .
    If i was you id put $100 per month into an account , and do some study on solar  . this site is excellent . Buying piecemeal is not a good idea .
    Work out what you hope to achieve . first . 
    Follow some threads for a while and you will see mistakes and good advice .
    It can be interisting.
    All the best  Peter
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . victron battery monitor . 24 volts 450 ah surette batterys . off grid  holiday home 
  • drops101drops101 Posts: 4Registered Users
    I hear ya well I'd like to have a offgrid system that's my goal but only something more for like emergency id like to maybe have 3 good amp circuits I can run independently off my electric panel

    Just something like a fridge a tv and something I can use to charge devices

    I currently have two batteries each 75 ah wired in series

    And a 1800 watt pure sine wave inverter
  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    Not sure what you mean by "3 good amp circuits" I run my home off an 1800 watt inverter, I just don't run everything at once.

    If you have 2 batteries run in series, I would assume you have a 24 volt system? 

    More questions than answers, for us as we can't determine what you have or want. I will say that off grid electric will cost more than grid electric in most of the country, perhaps a few places in Hawaii where they pay 40+ cents a KWh and even then you would have to have an energy use profile that closely matches the available sun.

    There will be a problem with shipping if you want to get the most for your dollar. Unless you live in south Florida or near San Francisco or Los Angeles. Where you can drive by and pickup panels at very low cost. Doesn't cost 3x the price to ship 20 panels as it does to ship 1. So easier to buy at once.

    If you have a 24 volt system, It's likely you could benefit from inexpensive PWM charge controller(s) and true 24 volt nominal panels. Of course you don't mix new and old batteries, so likely the only savings would be with your inverter. If you do have 2 - 12 volt batteries in series, I would think it's likely you have a 1800 watt Iris inverter? Not a lot of 1800 watt inverters in 24 volt, Iris or Prosine are the ones I'm familiar with, lots of Iris inverters have been getting cycled out from the military.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • drops101drops101 Posts: 4Registered Users
    3 20 amp circuits sorry I must have not put the 20 and no sorry mine is ran in parallel idk why I stated series, I have electricity at my home that's not the issue I just want it for days power lines aren't working, threes times where it is off for 3-4 hours I live in the country(Texas/austin) also I like the idea of having offgrid power end of days kinda thing I have a generator also that's runs off gas and propane
  • drops101drops101 Posts: 4Registered Users
    That's my set up
  • mcgivormcgivor Posts: 1,761Registered Users ✭✭✭✭
    edited May 12 #7
    First lesson, when batteries are placed in parallel the charge/ discharge cables should be connected  diagonally, not both on the same battery, read this information for a clearer understanding. http://www.smartgauge.co.uk/batt_con.html
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    I guess if you read my reply, you understand that 3 - 20 amp circuits is not a measure of electric. If you have goals, like I'd like to keep a freezer and fridge running. or I'd like to try to have a freezer, single room air conditioner running... That would be a specific load we could address. 3 - 20 amp circuits running at capacity is a huge amount of electric and you likely don't use 3 x 20 x 24 (hours) x 120(volts) x 30 days = 5,184,000 watts or 5,184 KWhs a month!

    My system could run a mini split air conditioner, a fridge and deep freeze and some lights, TV/computer or about 20 KWhs a day during the summer. I have a 5000 watt array, and a Forklift battery, though only 16 Kwh's of storage. I use nearly that with a single 1800 watt inverter, though it is pretty heavily burdened. The cost would be somewhere in the neighborhood of $10K. Though if installed in your home there is a 30% tax credit off of any liability you have through 2020, and decreasing after that...

    In general if your goals are that high, You should think this out in stages. You will, in time, dump everything you have now!

    New and old batteries don't mix well, and a 12 volt system will have problems handling high amperage with out huge wires. I only have a 24 volt system and really should be a 48 volt system, but I had already bought the battery for an smaller cabin system, and it would be hard to sell a used $2500 battery. So I used what I had when forced to move and likely will switch when the battery needs to be replaced.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • BB.BB. Posts: 27,445Super Moderators admin
    A "small" system includes LED lighting, laptop computer, small fan, cell phone charging, running a non-laser printer, and such. Call this 500-1,000 Watt*Hours per day (30,000 WH or 30 kWH per month).

    A "medium" sized system--Add 1 refrigerator. Maybe a small well pump, washing machine, LED TV... Around 3,300 WH per day (or ~100 WH per month).

    An issue with off grid solar power systems--They are not "cost effective" as pure backup systems. They only "make/save" money if you are using them (saving gas/propane for genset, not paying for Utility connection, etc.).

    If you want 3 days of backup... A 5-10 gallons of gasoline with preservative (or propane equivalent) genset is cheap and reliable. And, store upwards of 20-30 gallons of gasoline, you can have 10+ days of backup power running a Honda eu2000i (1,600 Watt) genset (roughly 9-4 hours of run time per gallon of gasoline).

    If you want >1 month of backup power (or will be running "off grid") for upwards of 9 months or more, a solar powered system (with good size battery bank) starts to make sense.

    In general, an off grid solar power system is expensive, has maintenance (check flooded cell batteries once a month, etc.) and for a "small" system, running a 300 to 1,200 Watt inverter is about maximum. And to run a refrigerator plus a few odds and ends, you are looking at a minimum AC inverter of ~1,200 to 1,500 Watts plus a good sized battery bank and solar array... For emergency backup power (and cost effective off grid solar power), you need to minimize your loads and make sure you have efficient appliances/loads (gensets are usually much better for short term, hours/a handful of days of backup power).

    To give you a quick idea of what a full time very energy efficient solar home system would look like (100 kWH per month/3,3 kWH per day) using our nominal design rules... Battery bank for 2 days of backup power, 50% maximum discharge (for longer life):
    • 3,300 WH per day * 1/0.85 AC inverter eff * 2 days storage * 1/0.50 max discharge * 1/24 volt battery bank = 647 AH @ 24 volt batter bank

    That is, roughly 12x 220 AH @ 6 volt golf cart batteries.

    To charge such a bank... 5% to 13% rate of charge is typical... 10%+ for full time off grid:

    • 647 AH * 29 volts charging * 1/0.77 panel+controller derating * 0.10 rate of charge = 2,437 Watt array nominal

    And based on where you live--The hours of sun may look like (fixed array) for Austin Texas:

    http://www.solarelectricityhandbook.com/solar-irradiance.html

    Austin
    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 60° angle from Vertical:
    (For best year-round performance)
    Jan Feb Mar Apr May Jun
    3.82
     
    4.18
     
    4.86
     
    5.27
     
    5.19
     
    5.65
     
    Jul Aug Sep Oct Nov Dec
    5.90
     
    5.72
     
    5.31
     
    4.87
     
    4.07
     
    3.67
     

    Say, if you have less than 4 hours of sun per day, you will use a genset/cut back on power used, the array needed to support the maximum "daily load":

    • 3,300 WH per day * 1/0.52 off grid AC solar system end to end efficiency * 1/4.0 hours per day of sun (non-winter) = 1,587 Watt array "Break Even" for 4.0 hours of sun per day...
    So, you will be looking at a nominal 1,587 to 2,437 Watt array for full time 3.3 kWH per day system.

    If you only wanted 1,000 WH per day, then divide the above by 3 ... Battery bank with 4x golf cart batteries (possibly a 12 volt battery ~440 AH @ 12 volts bank), a 300-600-1,000 Watt AC inverter and ~500-800 Watt array.

    Not saying the above is "the only answer"--Just more of a starting point in the discussion to help you figure out where you want to go.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • littleharbor2littleharbor2 Posts: 915Solar Expert ✭✭✭✭
    Definitely save your money for some 260- 300 watt grid tie type panels. 100 watt 12 volt panels are way more expensive per watt.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • mcgivormcgivor Posts: 1,761Registered Users ✭✭✭✭
    edited May 13 #11
    Definitely save your money for some 260- 300 watt grid tie type panels. 100 watt 12 volt panels are way more expensive per watt.
    True the GT panels are cheaper, but using them requires a more expensive  MPPT controller,  at ~30v vmp too high for a 12V nominal, too low for 24V nominal PWM setup, just heads up information for the benefit of @drops101
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    mcgivor said:
    Definitely save your money for some 260- 300 watt grid tie type panels. 100 watt 12 volt panels are way more expensive per watt.
    True the GT panels are cheaper, but using them requires a more expensive  MPPT controller,  at ~30v vmp too high for a 12V nominal, too low for 24V nominal PWM setup, just heads up information for the benefit of @drops101

    Well if you are going that far, you might also let him know that some/most of the higher wattage >300watt new panels are true 24 volt/72 cell panels that can be used with a cheaper PWM charge controller in 24 and 48 volt configurations.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • littleharbor2littleharbor2 Posts: 915Solar Expert ✭✭✭✭
    edited May 13 #13
    mcgivor said:
    Definitely save your money for some 260- 300 watt grid tie type panels. 100 watt 12 volt panels are way more expensive per watt.
    True the GT panels are cheaper, but using them requires a more expensive  MPPT controller,  at ~30v vmp too high for a 12V nominal, too low for 24V nominal PWM setup, just heads up information for the benefit of @drops101

    True.  There are 72 cell 24 volt GT panels as well,  275 - 345 watt range fine for 24 and 48 volt systems and PWM

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • mike95490mike95490 Posts: 7,654Solar Expert ✭✭✭✭
    download this book, or buy the most recent version. it'll give you a lot of info.
    https://archive.org/details/fe_Solar_Power_Your_Home_For_Dummies

    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 ,

  • PluckaPlucka Posts: 24Registered Users ✭✭
    Over the years I've wasted so much money on solar and have learnt that I should have done it the right way once.I now have it sorted for my caravan offgrid. 1000 watts of branded panels 360 amp/hr lithium batteries, mppt controller and 3000watt pure sine inverter. In Australia it cost me $4500 .DIY
  • NANOcontrolNANOcontrol Posts: 48Registered Users ✭✭
    mcgivor said:
    Definitely save your money for some 260- 300 watt grid tie type panels. 100 watt 12 volt panels are way more expensive per watt.
    True the GT panels are cheaper, but using them requires a more expensive  MPPT controller,  at ~30v vmp too high for a 12V nominal, too low for 24V nominal PWM setup, just heads up information for the benefit of @drops101
    I guess I didn't get the message.  Here is my $5 grid tie MPPT to 12V running off four 280W panels.
  • PhotowhitPhotowhit Posts: 4,544Solar Expert ✭✭✭✭
    mcgivor said:

    Here is my $5 grid tie MPPT to 12V running off four 280W panels.
    Could you explain this statement? I got $5...
    What is 'grid tied'?
    Meter does appear to be reading charging voltage for 12V, curious at what current? and what regulation?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • NANOcontrolNANOcontrol Posts: 48Registered Users ✭✭
    I just arrived at camp for the season. It was miserable, rainy and I'm trying to boot up the fridge from zero. Last year I bought 6 additional 280W 60 cell grid tie panels, I've only mounted up four of them so far in a 2S2P configuration for about a 60V power point. Last year they only powered the dishwasher heater and a space heater.  These are automotive 72V to 12V converters that are my absolute favorite for making into about anything like linear current boosters.  A quick mod and the 12V can be boosted to battery voltage.  Another mod makes them operate a panel at its power point, MPPT (turning).  It has a opto isolator referenced to common so it is quite easy to make a true MPPT with a micro.  Rated at 15A, I wouldn't use it at more than 6A continuous. But you can take a number of them in parallel for higher current.  As my system only has a single battery, an extra couple of amps is all I need in low light levels.  The rest of the power heats water at power point. It is dirt cheap solar that out performs systems at three times the cost. That meter is just hanging there for another part of the system.
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