hybrid setup experience?

asadlarik3asadlarik3 Registered Users Posts: 9 ✭✭
hello

I am planning for solar setup. Maximum load is 12000 watts (5000 home 7000 air conditioners). 
Grid is down for intermittently for 6 hours (4hrs day+ 2hrs night).

In my ideal setup i would want to generate all my energy use for 24 hours period within the 5-6hours of sunshine during the day from grid-tie inverters. But as the grid is down during 4 hours in day, so in pure grid tie system these 4hours will be wasted.

I am planning 20kw solar panels in installments.

The biggest and worrying cost is that of invereters.

So if i select this 4x inverter http://www.wholesalesolar.com/2931725/sma/inverters/sma-sunny-boy-5.0-us-inverter that would be 8500usd plus shipping and taxes to my country. but this looks preferable because 3mmpt connections.

Now for these 4 hours of grid outage, i need to put hybrid invereters for Ac-coupled sytem, my eyes are on http://www.wholesalesolar.com/2550525/outback-power/inverters/outback-power-outback-vfxr3048e-3.0kw-48v-230-vac-export-grid-hybrid-vented-inverter.

So now considering that my house load is 5000 watts, if i put two 3000watt hybrid inverters in mini grid mode with a very small battery bank, will it allow me to drive power from all the 20kw grid-tie setup during day time, so that i may use this to power all 12000watts, and when during night time when solar power is off the hybrid inverters will only be used to power my 5000watt home load in case grid goes down.

also there is the case that the solar power produced is less power say 3000watts, but the load say is 11000watts, then the system will try to draw 8000watts from hybrid inverters which will be 2000 watts more than 6000watts of rated power of hybrid inverters. So can there be any mechanism to monitor power produced by solar panels or the grid-tie inverterts and based on this instantaneous value the load is automatically controlled ( say air-conditioners) on-off so that at all times power drawn from the hybrid inverters is less than 6000 watts.

I would like your comments on my plan. keeping the cost per watt of solar produced lowest during the lifetime of system is the ultimate goal which can be achieved by either lowering cost of equipment, producing maximum power from equipment and doing away with enormous battery costs.

Comments

  • mike95490mike95490 Solar Expert Posts: 9,358 ✭✭✭✭✭
    edited March 2016 #2
    If you don't regularly have 5 day plus outages (at least 2 per month), you don't need batteries, you need a generator that can run your critical loads.  The batteries are a large expense, and get replaced every 5-10 years. Otherwise you are taking on the whole ownership mess of batteries and charging - AND you need a generator anyway, because the ice storm that took out all the power poles, also shredded half your solar panels and it's still cloudy, drain the batteries too low and they are toast,

    With batteries, you never break even, you have your regular electric bill minus the solar offset, plus the battery cost.
    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 ,

  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    Where do you live? I tend to agree with Mike in the previous post but location on the globe can tilt my answer.
    With the price of propane up here in the Sierra at $1.29 it is hard for someone like you to justify batteries.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Guessing "asadlarik3" is around Karachi or Hyderabad Pakistan. And it is possible that there are "common" afternoon power failures for 4-6 hours at a time.

    Batteries are the main cost/weakness of any solar power system that can store energy locally.

    If your system would support "near daily" power outages--Battery+AC Inverter can be cost effective. Using AC Mains/Solar Panels/Backup Genset is simply a math exercise. Does solar array save you money (say ~20 year array life) vs paying the utility to recharge your battery bank. And do you have power failures > 1-2+ where solar and/or backup genset is "worth it to you".

    As you can see, solar/backup power is not cheap. Solar makes sense if you use it >~9 months of the year. A backup genset (assuming you can fuel/run one in your location) makes sense if you are using the backup system ~2 weeks or less of the year.

    Remember that the life of the electronics (inverters, charge controller) is ~10+ years. Lead acid Batteries have a life of ~5-7 years (deep cycle batteries) or upwards of 15-20+ years (forklift/industrial Lead Acid batteries). And--It is "very easy" to kill the battery bank with over discharging, over charging, forgetting to fill with distilled water (boiling battery bank), etc. Bad maintenance/operation can kill the battery bank in months, if not weeks/days--So having the money to recover from mistakes is important. Many first time off grid power users "murder" their first battery bank until they understand what is needed to operate correctly.

    If you can reduce your loads (minimum LED lighting, laptop computers vs large computers, fans instead of AC when AC mains are down, etc.) can reduce the size of your backup power system--Saving intitial costs and onging maintenance costs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    Hey Bill,
    Hope you are well !  Can I ask how you knew the OP's location?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    Hi Dave,

    Surviving... Been really busy with some house repairs (leaking windows in stucco residence--bunch of fun).

    Regarding guessing at a poster's location: Forum software packages generally save the IP Address of each post. A decade ago, the IP Addresses were visible to all users. But a few were concerned about privacy, so the IP Addresses are only visible to moderators/admins.

    With the IP Address, I use something like this website to "guess" at the location of the poster. Can be pretty accurate 80% of the time, and really wrong ~5% of the time ("things change" in the network, traveling, work vs home vs vacation home vs cell phone network, etc.):

    http://geobytes.com/iplocator/

    There is no physical location meaning to IP Addresses:

    http://compnetworking.about.com/od/traceipaddresses/f/ip_location.htm
    So-called geolocation systems attempt to map IP addresses to geographic locations using large computer databases. Some geolocation databases are available for sale, and some can also be searched for free online.
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    edited March 2016 #7
    Thanks Bill,

    Good to know that it is secure.  I know you remember the reason I got to use my real name after 10 years of hiding from the bad guy's we met one night in the Caribbean.,
    I guess I was exposed back then thru the internet? Now I do have the creeps!  Well good thing most bad guy's are not real bright :)

    Yes I do remember Stucco, good times not!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • BB.BB. Super Moderators, Administrators Posts: 32,006 admin
    To actually connect an IP Address to a specific home/business... The government needs a warrant to have Comcast (or whomever) connect a specific IP Address to a specific residence.

    IP Address may be fixed (static)--Common for server farms, companies, etc. (costs more).

    Or they may change in hours/days/weeks (not-static). And for homes, businesses without servers, they can change over time.

    But--as always, there are people collecting data. If somebody in the house orders from Amazon, and a data company buys IP Address to Zip code or physical address--They can get an approximate or exact location match (at that point in time) of a user to IP match (home, work, school, cell phone network, etc.).

    And this is the problem with having wireless routers. There is one faction that says leave your wireless router without a password--So anybody can share your Internet connection. And because random people can use your access... The courts cannot 'prove' that some behaviour (stuff the government does not like) is traceable to you (at least without a lot of extra work).

    The downside, you get bad folks that want to download illegal materials and/or do hacking and the IP Address is connected to your home. There bad behaviour can cause you a lot of grief if the government gets a report that IP A.B.C.D is doing bad things.

    So--I would suggest a good password on any wireless router... Don't let your connection be shared. And many companies (like Comcast) have a monthly data limit (currently around 300 GBytes per month currently?) and sharing your internet can cost you money (especially if you use satellite or cell phone internet with much lower limits).

    Keeping IP Addresses "private" on the forum--Not "high security", but can make it more difficult for the bad guys (and hardly slow the government/data brokers down).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    Our wireless router is pretty secure because the gate is locked 1/2 mile away....I do have to share it with my wife, starting to worry again!

    Thank-you though for the info. The boating bad guy died in a Mexican prison. The Coast Guard sent me a picture.

    Get back to the Stucco!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • asadlarik3asadlarik3 Registered Users Posts: 9 ✭✭
    edited March 2016 #10
    BB your are right its Hyderabad, Pakistan. 6 hours total of daily power outages.
    On the batteries:  I do have a 4000+ watt portable generator on natural gas used during grid outages BUT as i told i have considered batteries to operate mini grid via hybrid inverters, so that i can harvest solar energy from panels while grid is off. While i will be maintaining a battery bank why not use in the the 2 hours during night time grid outage?

    For solar vs electricity cost. My electricity unit costs around .15 US cents and maybe some additional taxes, which i think you will see that is on high side. the panel i have seen is sunedison 330watt around .7cents/watt locally available.

    If i keep the costs of my inverters and battery bank down, system payback can be in 6-7 years or lower.

    for lead acid battery life how much cycle life can you achieve in 6-7 years? if i consider my case if i get aound 6000watt hours of battery capacity that would be around 2200 cycles per year at 80% DOD. So i will have to replace the batteries pretty much every year. If i limit the DOD the cost of initial battery investment dramatically increases. but in the long run battery costs do come down.

    Also the mini grid setup that i described in original post, has anyone had any experience with a similar system?
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    The TL series from SMA will operate 1500 watt loads when the sun is out even with the grid down. I would look at it.
    It is easier to AC couple if all the equipment (inverters) is from the same company as it will be guaranteed to work. Good Luck
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • asadlarik3asadlarik3 Registered Users Posts: 9 ✭✭
    edited March 2016 #12
    The TL series from SMA will operate 1500 watt loads when the sun is out even with the grid down. I would look at it.
    It is easier to AC couple if all the equipment (inverters) is from the same company as it will be guaranteed to work. Good Luck
    that secure power supply, i dont know whether you can combine this output for multiple inverters and supply to single load center or loads have to be split for 1500watts, also power is not stable so i will have to again use a AC battery charger that can work with fluctuating amps and charge batteries.  but the basic problem is that for every 5000watt inverter i will have 3500watt of idle solar power for 4 hours everyday.

    Yes for sma grid-tie i should use sunnyisland as hybrid inverter for mini grid but it will cost 30% more for same power. 
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    edited March 2016 #13
    It really does not cost more for the TL and so I would buy it just to have another way to charge small equipment. The output is very steady in secure mode as long as the sun is steady!  It does not use your unstable utility in this mode.

    You should also shop the store here, they can compete and are very competent!

    It does not matter how much you save on equipment if it does not work and the same thing for the person who installs it. Learn how the SMA drives the outback if that is what you will use in a power outage. Make sure they are compatible for AC coupling. This is what it is called BTW and I believe you referred to it as mini grid.

    Bill can help you with the rest of that but I still would lean at a nice quiet electric start propane/natural gas generator.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • bill von novakbill von novak Solar Expert Posts: 891 ✭✭✭✭
    asadlarik3  that secure power supply, i dont know whether you can combine this output for multiple inverters and supply to single load center or loads have to be split for 1500watts, also power is not stable so i will have to again use a AC battery charger that can work with fluctuating amps and charge batteries.  but the basic problem is that for every 5000watt inverter i will have 3500watt of idle solar power for 4 hours everyday.
    Well, it's better than 5000 watts of idle solar power every day.  The benefit of the SMA secure power supply is not that it's a great backup source of power, but that it is a backup source of power that is free and does not require any batteries.
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,028 ✭✭✭✭✭
    It looks like this years SMA models have been raised to 2KW for the secure supply mode. Might be enough to start a medium refrigerator/ freezer and plenty for a large soft start reefer.  
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

Sign In or Register to comment.