upgrade time

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leeelson
leeelson Registered Users Posts: 18 ✭
in Solar Beginners Corner #1
I've finally decided to take the plunge and upgrade my system:

We currently have 2 sets of 9-208 watt Sharp PV panels connected to a grid tied Sunny Boy SMA 3800. I believe the AC output is around 3000W. We want to add 6-250W (about 1240W AC) panels as well as some battery backup. The total AC output would be about 4300W. The intent is to maintain the grid tie but also have all the panels available when the grid is down. I believe the Sunny Island will do this. My question is: what is the smallest Sunny Island that will work for this application? I believe that the SI4248, SI5048 and SI6048 all have similar capability but different power output limitations. Is this correct?

We're also considering a Xantrex. Can we use the XW4548 rated at 4500W?

Thanks for any suggestions.
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  • DanS26
    DanS26 Solar Expert Posts: 266 ✭✭✭
    #2
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    Re: upgrade time

    Your intent is to "maintain the grid tie". Then you should forget the battery option......much too expensive. Much better to expand the grid tie and purchase a backup generator.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #3
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    Re: upgrade time
    leeelson wrote: »
    ......We're also considering a Xantrex. Can we use the XW4548 rated at 4500W?....

    The xw4548 will sell to the grid, but you will need to get a 48V PV charge controller. And the xw6048 is only a little bit more, for a lot more capacity. You will with the XW, need a controller box, either a SCP or a Conext ComBox. I think you need a controller box for the SMA too (not sure- I dont own any SMA gear)

    And then, the PV needs to be converted with a charge controller, to 48V for the batteries, with a Charge Controller.
    The 60A, 150V PV models, at 55V battery charging voltage, handle about 3,000 watts.
    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 ,

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  • leeelson
    leeelson Registered Users Posts: 18 ✭
    #4
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    Re: upgrade time
    DanS26 wrote: »
    Your intent is to "maintain the grid tie". Then you should forget the battery option......much too expensive. Much better to expand the grid tie and purchase a backup generator.

    Money's no object. ;-) Thanks for the advice but that's not what I asked about.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #5
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    Re: upgrade time

    I don't know a lot about the SMA Sunny Island... But to start, some questions and rules of thumbs:

    1) Can an SMA GT inverter operate both as on a Sunny Island and on a Utility Grid with a simple transfer switch (I thought one would have to configure an SMA GT inverter for SI or GT operation as the two modes control power flow differently... GT inverter is 100% of available power to the grid if voltage and frequency is good--Sunny Island Mode will 'modulate' flow from the solar array to the local "micro grid" based on current loads/battery charging needs responding to modulated 60 Hz +/- small frequency shifts). You can (I think) run in Utility GT Mode with the GT inverters, it is just they do the "on/off" regulation thing instead of a smooth percentage variation based on system needs (the SMA SI system--very cool and not cheap).

    2) A good "cost effective" maximum array is about 1/0.77 times larger than the rated output energy... For example:

    3,000 watt output * 1/0.77 panel+controller deratings = 3,896 Watt array

    At this size of solar array, during cooler/bright/clear days, you may hit the maximum limit for a bit during these times in the middle of the day--It won't hurt the controller or cost you (typically) that much loss power.

    3) Pick your voltages... In the US, most GT inverters are 240 VAC. However most household loads are 120 VAC. And you have a choice of 120 VAC Off Grid inverters or 120/240 VAC off grid inverters (typically larger and more complex types).

    So, matching your existing GT inverters to the arrays and the the 120/240 VAC needs of your home--Plus the physical size of your battery bank... Larger battery banks can manage larger arrays--And need larger arrays to properly/quickly charge the battery bank.

    And back to the first question I always like to ask--What are your loads and battery bank needs?

    So--To make things a little easier to design... What is "your" desires/needs?

    Nominally, I would like to know your loads (voltage, average wattage, Watts*Hour per day)... That defines the battery bank. The Battery bank + Loads define the Array and any backup charging/generator.

    However, you can start with a battery bank (say 8x 6 volt @ 220 AH golf cart batteries--2series*4parallel for 12 volt bank, 4s*2p for a 24 volt bank, or 8s for a 48 volt bank).

    Or, you have an existing configuration of arrays and GT inverters, what size battery bank would it support, and how many kWH per day could you get from the system (over the 4 seasons)?

    Any of these are valid methods to start a design--But I am not quite sure what you are looking for.

    The suggestion for a GT inverter + backup genset + fuel storage is one where you are looking at less than 2 weeks of outages at a time.

    You can go with a hybrid solar power system (solar+hybrid inverter for GT/OG power+battery bank) which can give you GT feeding power back to the grid and still let you have AC power when the grid is down.

    And there is the Off Grid system--You plan on not using the grid much (or disconnect) and use solar plus backup genset for your power needs. To be "cost effective", an off grid power system should probably be used for ~9+ months a year--It is (usually--Depending on utility costs) not very cost effective when used only in emergencies or for weekend/seasonal cabins.

    For utilities that do not allow GT solar (or charge an arm and a leg for metering and the "privilege" of backfeeding power), an Off grid power system or a "UPS" style (uninterruptable power supply--With or without solar) is an option.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • DanS26
    DanS26 Solar Expert Posts: 266 ✭✭✭
    #6
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    Re: upgrade time
    leeelson wrote: »
    Money's no object. ;-) Thanks for the advice but that's not what I asked about.

    I'm trying to understand the "money's no object" mindset. No offense intended, I just need to know. I understand battery based backup systems when no alternatives are available (ie no grid connect). Is the fact that you can survive without the grid in an emergency the driver or is that you can impress your neighbors by getting by without that noisy generator?

    IMHO these battery based systems when there is a grid available is not logical. At least from an economic or environmental standpoint. But I do see the argument when the grid goes down "FOREVER". So is that it.......you are preparing for a long term, grid disaster?

    Really, just trying to understand your mindset.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • leeelson
    leeelson Registered Users Posts: 18 ✭
    #7
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    Re: upgrade time
    DanS26 wrote: »
    I'm trying to understand the "money's no object" mindset. No offense intended, I just need to know. I understand battery based backup systems when no alternatives are available (ie no grid connect). Is the fact that you can survive without the grid in an emergency the driver or is that you can impress your neighbors by getting by without that noisy generator?

    IMHO these battery based systems when there is a grid available is not logical. At least from an economic or environmental standpoint. But I do see the argument when the grid goes down "FOREVER". So is that it.......you are preparing for a long term, grid disaster?

    Really, just trying to understand your mindset.
    Grid failures don't fall into 2 categories: short enough for a genset to handle and FOREVER. It not out of the question for the grid to be down longer than the realistic operating life (without maintenance & repair) of a genset. If you've ever used one for more than 24 hours (I have) you know that they are noisy and inefficient. It has nothing to do with impressing anyone.

    It should be obvious that few people install a PV system based on cost only. That's certainly the case for me. Why would you expect someone to set up a grid dependance or lack thereof based only on costs? Putting it another way, IMHO (using these) PV based systems when there is a grid available is not logical.

    Do I think the grid could go down long term (> few days)? Sure. Is it likely? No, but neither is a car crash or getting cancer. Still, we take precautions partly out of peace of mind. If the Internet survives armageddon, I'll bet there will be some interesting posts about battery backups. ;-)
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  • DanS26
    DanS26 Solar Expert Posts: 266 ✭✭✭
    #8
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    Re: upgrade time
    leeelson wrote: »
    Grid failures don't fall into 2 categories: short enough for a genset to handle and FOREVER. It not out of the question for the grid to be down longer than the realistic operating life (without maintenance & repair) of a genset. If you've ever used one for more than 24 hours (I have) you know that they are noisy and inefficient. It has nothing to do with impressing anyone.

    It should be obvious that few people install a PV system based on cost only. That's certainly the case for me. Why would you expect someone to set up a grid dependance or lack thereof based only on costs? Putting it another way, IMHO (using these) PV based systems when there is a grid available is not logical.

    Do I think the grid could go down long term (> few days)? Sure. Is it likely? No, but neither is a car crash or getting cancer. Still, we take precautions partly out of peace of mind. If the Internet survives armageddon, I'll bet there will be some interesting posts about battery backups. ;-)

    What I hear you saying is that you are preparing for a grid down scenario that is long but not forever. At least longer than a typical home based generator is capable of handling. Fair enough. When your neighbor's generators are all used up, say in a few weeks or months, and fuel is impossible to find, then your battery based PV system will still be going strong. Sounds like a good plan to me.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
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    Re: upgrade time

    Sometimes the grid can go down at inopportune moments; like when you're not there to start the gen or maintain it. If you're trying to protect critical items battery back-up power is sometimes worth the investment. We can't all stay home all day fueling the gen just because there's a localized power outage.
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  • DanS26
    DanS26 Solar Expert Posts: 266 ✭✭✭
    #10
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    Re: upgrade time
    Cariboocoot wrote: »
    Sometimes the grid can go down at inopportune moments; like when you're not there to start the gen or maintain it. If you're trying to protect critical items battery back-up power is sometimes worth the investment. We can't all stay home all day fueling the gen just because there's a localized power outage.

    Agree.

    Being prepared is different for each person and situation.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #11
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    Re: upgrade time

    read this statement a few weeks ago, ' we all have insurance, (right?) but we don't plan on needing it'.

    Which begs the question, If we don't plan on needing it why do we have it?

    Well in my case I like to try to cover the unlikely eventuality.8)
     
    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,
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    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #12
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    Re: upgrade time
    westbranch wrote: »
    read this statement a few weeks ago, ' we all have insurance, (right?) but we don't plan on needing it'.

    Which begs the question, If we don't plan on needing it why do we have it?

    This is the Insurance Paradox. We don't plan on needing it because experience tells us they won't pay the claim anyway. :p
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #13
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    Re: upgrade time
    Cariboocoot wrote: »
    This is the Insurance Paradox. We don't plan on needing it because experience tells us they won't pay the claim anyway. :p

    Actually over the years I have had a couple insurance claims and been totally happy with the results. The last big hail storm we had here I got all the cars repaired, the house completely painted and stucco repaired and all new screens installed. My out of pocket was about $50.

    About 10 years ago I had the wife's car stolen right out of my driveway, they paid for a rental for the full 30 day waiting period and then paid us about $500 more than we paid for the car 2 years before when we bought it used. They even kicked in $750 for personal property in the car. It almost covered the brand new car I bought the wife on an end of year deal from the dealer.

    I added the solar and told them the installed cost, no increase in premium, then added the new building which I got put up for about $50K and told them what it was and sent them pictures and the increase in premiums for an additional $100k (they insisted it was worth $100k) was only about $80 a year.

    Personally I think it is choosing a good company not necessary the cheapest premiums.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #14
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    Re: upgrade time
    solar_dave wrote: »
    Personally I think it is choosing a good company not necessary the cheapest premiums.

    Province of British Columbia: mandatory automobile insurance provided by Crown Corporation. No competition allowed. Secondary insurance is available from private industry, but the CC subsidizes their secondary rates with income from the mandatory primary. We are currently in legal process to get money owed.

    Like so many things, it isn't the same everywhere you go.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #15
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    Re: upgrade time
    Cariboocoot wrote: »
    Province of British Columbia: mandatory automobile insurance provided by Crown Corporation. No competition allowed. Secondary insurance is available from private industry, but the CC subsidizes their secondary rates with income from the mandatory primary. We are currently in legal process to get money owed.

    Like so many things, it isn't the same everywhere you go.

    Sounds like assume the position situation. Unbelievable!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #16
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    Re: upgrade time

    Just got a $363 a month increase in health insurance for a family of four (24%). My whole policy (with much lower deductibles) was $250 ~4 years ago and 5$500 2.5 years ago for our family. May be going without health insurance for the first time in almost 6 decades very soon.

    Because of this:

    http://healthland.time.com/2014/01/29/north-carolina-hospital-bill-snake-bite/
    The hospital, Lake Norman Regional, defended their pricing in a statement to the newspaper: ”Hospitals only collect a small percentage of our charges, or ‘list prices.’ We are required to give Medicare one level of discount from list price, Medicaid another, and private insurers negotiate for still others. … If we did not start with the list prices we have, we would not end up with enough revenue to remain in operation. … Our costs for providing uncompensated care are partially covered by higher bills for other patients.”

    I am a fool for paying my own bills.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #17
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    Re: upgrade time
    BB. wrote: »
    My whole policy (with much lower deductibles) was $250 ~4 years ago and $500 2.5 years ago for our family. May be going without health insurance for the first time in almost 6 decades very soon.

    Wow! your cost went up 100% (from $250 to $500) in just 18 months! :cry:
    BB. wrote: »
    Just got a $363 a month increase in health insurance for a family of four (24%).

    What a relief! It's slowed down to 24% per year :D

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #18
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    Re: upgrade time

    Since I got laid off I have been riding on a Cobra plan for the wife and I, $1088 a month! Ouch!!!

    Because we now have a very low income, we signed up for Obamacare, better policy, lower copays, no deductible, $363 a month with same insurance company, even the same subscriber ID, just a new Group ID. Uncle Sugar covers $655 a month on the premiums. ;)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #19
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    Re: upgrade time

    Well when it comes to healthcare ours is "free": about 50% of every dollar the average Canadian earns goes to pay for this free healthcare. Due to poor policies the system is severely overburdened in places so people (like me) end up waiting months for services and even appointments.

    But this thread is wandering far away from the purpose of the forum.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #20
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    Re: upgrade time

    Yea--Kinds of makes my "investing" money in a Grid Tied Solar system 10 years ago because I was somewhat concerned that my $30 per month electric bill might double in 10 years look "cute".

    Sort of like avoiding sex/drugs/rock and roll (not easy when going to school in San Francisco in the 1970's)--And missing all of the "fun" in life to have a long, boring, and healthy life.

    This news-report (video) was a few years before my time at SFSU. Old Chinese curse... "May you live in interesting times".

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #21
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    Re: upgrade time
    solar_dave wrote: »
    Uncle Sugar covers $655 a month on the premiums. ;)

    Not Uncle Sugar...it's the rest of us footing the bill...we all pay higher premiums to make up for the fact that now EVERYONE can get coverage regardless of their health (not in any way implying anything about yourself personally).

    My coverage went up $124 a month. BUT, I am glad to know that now, I, as a SINGLE MALE, have "maternity coverage" and substance abuse coverage! So when I, as a male, end up pregnant, I can drink myself into a depression and have coverage to help get out of it :)
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • ILFE
    ILFE Solar Expert Posts: 364 ✭✭
    #22
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    Re: upgrade time

    I am so glad I am living abroad and not having to deal with ObamaCare, or its premiums. What a joke. Unfortunately it is on us, American Citizens - the American taxpayer. Much better for me to be self insured, as I have been for 1.5 decades.

    Anyway, I am glad to have been in a position, although not necessarily by choice, to start an off-grid solar project for our little home. Even when they run grid power (supposedly sometime this year) down the road by our property, we will not use it. Solar is more reliable, and stable, than any grid power that you will get in many SE Asian countries.

    Yes, I know off-grid is not that efficient. But, I am willing to suffer through off-grid, knowing that I will have that stable, reliable power, regardless of the status of the local grid.

    So, no need of a hybrid, or grid tied system here. Just a specific gravity meter.
    Paul
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