newbie to solar--looking to install gridtie system

ldiorio
ldiorio Solar Expert Posts: 47 ✭✭
hi all have been reading forums and talking to a few solar companies to get quotes on a grid tie solar backup system

i have a 12KW propane gen with auto transfer switch that provided me power durning Sandy --
but i wanted another system that could supplement not having to run my gen for a prolong outage have a 240 volt well pump and my priamary focus is the feed some critcial ckts (boiler,ref well pump tv and a few lights) and secondary is selling to the grid

also wanted a basic system with ability to grow

i stated looking at a XW6048 with assoc modules,, 8-trojan L-RE-B batteries and 6- 240 panels--then some on other forums said that the company was bought out by a french company and some said that there were software problems --so i decided to look at a US company Outback Radian GS6048 system with GLSC175 and the mate 3--both units would provide 2 AC inputs( grid and gen)
one company recommended a epanel and not the GLSC -they said its a better unit

am a Verizon retired engineer which by training am concerned with a good operational system--
and something i can upgrade firmware and manage locally--i am very handy with electrical wiring so assembling units does not cause me a problem but some preassembly would be helpfull and looking at a full Outback radian system with matching units SEEM to be a good choice-but would mix and match if i can get a better system

any thoughts would be appreciated
lou

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system

    Welcome to the forum Lou.

    Xantrex is now owned by Schenider. The XW units have been around a while. They have a few flaws, some of which are very frustrating. The company's record on customer service is not stellar.

    Outback is now owned by Alpha Group. The Radian series in new and there's not a long/large install history to go by. Outback has a better reputation for customer service.

    The e-panels and other MidNite Solar equipment is well thought-of around here and the company's customer service is first class.

    You need to match up battery capacity to inverter size. For an 8kW inverter you should have at least 800 Amp hours of battery capacity. The single string of Trojan L16's is <400 Amp hours. Then you need enough panel and controller to recharge same. Six 240 Watt panels isn't going to be large enough. For the full GT experience you want an array about the same size as the inverter's output capacity so that you get maximum sell-back benefit.

    If this is primarily for emergency power purposes you might want to measure your critical loads with a Kill-A-Watt meter and size your system accordingly. You may not need such a big system. Then the sell-back becomes an offset of the investment. If you don't have a utility willing to buy (some of them make up difficult requirements in order to discourage GT) then you may want just a standby system, which opens up even more possibilities.

    Is that any help?
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    hi Caribo
    thanks for your thoughts-i appreciate yourdirect comments --i need that to help me arrive at a system

    FYI i did start witha pure backup system with batteries not tied to the grid but many said i should tie to both sell and have the grid charge the batteries and not have to use my gen unless the grid was down

    2 bacis points -i wanted to use my 240 12kw gen and also run my 240 volt well pump off the batteries in a prolonged outage
    the outback and xw has 2 ac inputs--but many told me of there concerns for the XW

    am not concerned about selling back to the grid-- my electric bill is about $120.00 per month so if i can sell it would
    be ok
    also not concerned with the 8000 watt capacity of the Radian i wanted to be able to grow if i had too in the future as i added loads to the system -my biggest load now on my transfer panel is the 240 well pump drawing 5Amps per leg

    I guess the way i would envision the system working is i would put my critcical ckts on a subpanel working off the batteries -batteries charged by the panels and the grid if the batteries get too low --if the grid is down the gen would repl the grid to charge the batteries--i was looking for a good operational system with room to grow--

    being a retired Verizon engineer i pay a lot of attention to details-at times that can be frustrating

    i didn't just want the batteries sitting around just for a grid outage

    does that sound ok
    give me your honest thoughts
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system

    I think you understand the situation very well. :D

    The Radian would need a big battery bank to reduce the AC ripple effect. That mean 800 Amp hours. If you want to charge that much from solar you'd need approximately 5kW of array for a 10% peak rate. You could possibly "get away with" half that and a 5% peak rate. In an emergency situation the panels may be under clouds and not producing much anyway, requiring more reliance on the generator.

    Check with your local utility and see what their GT requirements are. Very important to know if they'll pay a decent price for any surplus you generate. Most have a 10kW limit for back-feed, and you have to be sure your service panel can handle this as well. That's a whole 'nother can of worms right there. :p

    My own inclination is that if you're going to do a GT system anyway and you're going to have an 8kW inverter in it you may as well maximize the array and sell back as much as possible as these days the panels are really quite inexpensive (although we're still talking like $6,000 to $12,000 in panels alone).

    Do up a few different plans and see which way meets your goals best. If you're going to spend $20,000 +/- you sure want to spend it wisely.
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    hi again could you explain the AC ripple effect -- is the Radian a good base equipment for me even if i start with 8 batteries initally--could just use the grid to help charge batteries and at some future date add more panels and start to sell

    what do yo think about using a epanel instead of a GLDSC-175

    an off idea--if selling is not my big focus could i install a backup solar system with batteries not a gridtie system but some how use the grid just to charge the batteries with gen as a backup??--

    lou
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system
    ldiorio wrote: »
    hi again could you explain the AC ripple effect --

    Well I just went looking for a concise explanation - and found about 300 posts on it! :roll:
    Short form: on battery-based GT system the panels feed the batteries through a charge controller which turns on and off rapidly creating a pseudo-AC effect at the batteries/inverter input. If the battery bank isn't large enough to filter this the inverter can flip between sell/no sell like crazy as the influx of power from the panels can push the Voltage up quite a ways before the controller pulls it back down (by turning off). With a large enough battery bank the Voltage fluctuation is 'flattened' into a manageable amount, the power becomes current.

    Okay, that's a pretty horrible explanation. I think I've failed at explaining this in a simple manner. :blush:
    is the Radian a good base equipment for me even if i start with 8 batteries initally--could just use the grid to help charge batteries and at some future date add more panels and start to sell

    I still haven't seen a Radian install myself. Basically its like four FX inverters stacked. Without the grid-tie in use the operation becomes much simpler.
    what do yo think about using a epanel instead of a GLDSC-175

    I've never used either, because mostly I 'salvage' off-grid systems that are a complete mess and owned by cheapskates. :p But several of the forum members have used the e-panel and are delighted with it.
    an off idea--if selling is not my big focus could i install a backup solar system with batteries not a gridtie system but some how use the grid just to charge the batteries with gen as a backup??--

    Yes indeed. Very simple. Basically and off-grid inverter-charger that looks at the grid as a generator. As long as AC IN is active loads are transferred to the grid and the inverter runs in charge mode keeping the batteries up. Grid goes down, it switches to invert seamlessly. There's other ways to do it, but that's the simplest.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: newbie to solar--looking to install gridtie system
    Well I just went looking for a concise explanation - and found about 300 posts on it! :roll:
    Short form: on battery-based GT system the panels feed the batteries through a charge controller which turns on and off rapidly creating a pseudo-AC effect at the batteries/inverter input. If the battery bank isn't large enough to filter this the inverter can flip between sell/no sell like crazy as the influx of power from the panels can push the Voltage up quite a ways before the controller pulls it back down (by turning off). With a large enough battery bank the Voltage fluctuation is 'flattened' into a manageable amount, the power becomes current.

    Okay, that's a pretty horrible explanation. I think I've failed at explaining this in a simple manner. :blush:

    This kind of ripple will only be seen with a PWM controller, and the frequency of the on-off cycle will be pretty high.

    If the inverter only sees the peaks of the battery voltage, it can start up too soon or stay running too long as the batteries charge and discharge.

    Even if there is no ripple, the difference in voltage among a charging battery, a rested battery, and a discharging battery can cause an inverter to flip back and forth, although a lot more slowly.

    Typically the inverter will turn on at a higher voltage than it turns off at to limit this flip/flopping. But if there is a lot of AC on top of the battery voltage, the difference between the turn on (at peak of ripple) and turn off (at bottom of ripple) points may become very small.
    SMA SB 3000, old BP panels.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system
    inetdog wrote: »
    This kind of ripple will only be seen with a PWM controller, and the frequency of the on-off cycle will be pretty high.

    Uh, MPPT controllers function the same way at 'met' Voltage points.
    If the inverter only sees the peaks of the battery voltage, it can start up too soon or stay running too long as the batteries charge and discharge.

    The problem is when 'sell' is on it can instantly pull battery Voltage down below the sell point if the bank isn't large enough. Hence the 100 Amp hours minimum per 1kW of inverter (or panel - usually sized similar) on a 48 Volt system.
    Even if there is no ripple, the difference in voltage among a charging battery, a rested battery, and a discharging battery can cause an inverter to flip back and forth, although a lot more slowly.

    Usually not a problem if the inverter is programmed right. The 'sell' should only occur with a charged bank; the panels keeping Voltage above the set point and providing the energy, rather than the batteries.
    Typically the inverter will turn on at a higher voltage than it turns off at to limit this flip/flopping. But if there is a lot of AC on top of the battery voltage, the difference between the turn on (at peak of ripple) and turn off (at bottom of ripple) points may become very small.

    Yup. Dat's der bunny all right. :D
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    just an off idea for me to consider--

    what would a off grid system look like using the grid just to charge the batteries and if the grid goes down my gen could be started to charge the batteries ---i would have my loads working off the batteries to keep them active

    what would a simple system look like --

    1-inverter controller-maybe use a smaller one
    2-charge controller
    3-number of batteries (48V system)
    4-number of 240 watt panels

    if i use the grid to just charge do i need a 2AC inputs or just one for the gen

    likei saidmy monthly billis about $120.00 per month -not realy going to get much savings selling to the grid and i might save a bunch of money ?????
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system

    You can in fact have such a system with no solar panels at all. Essentially you'd be building your own UPS for critical loads.

    Suppose you use:
    Outback FX2524 http://www.solar-electric.com/fx2524t.html
    MATE programmer http://www.solar-electric.com/mate2.html
    Four 6 Volt 220 Amp hour batteries http://www.solar-electric.com/cr225am6vode.html
    Misc. hardware and wiring (fuse, et cetera).

    That would be a very minimal system which would keep the batteries charged via grid or generator and provide up to about 2.4 kW hours of run time. A bit under $3,000 there, and you could get bargains in batteries. You can also add solar later if you were so inclined.

    Or you could do the same in 48 Volt with an FX3648 and more batteries. Or you could buy a Magnum if you needed 240 VAC output http://www.solar-electric.com/maenms4444wa.html There are lots of possible variations on this theme.

    With such a system you would have a transfer switch to change between grid power and gen power to the inverter's AC IN.
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    hi

    this senario is very interesting to me --maybe start with a Magum unit to get 240 volts(for my well pump) and a 48volt battery backup Trojan L-16 RE-b with a gen switch

    with this plan how would i add solar panels( need panels and a charge controller) how would it connect and what would control the battery charging( panels vs grid)

    thanks
    lou

    then if i wanted to sell back to the grid i could change out the Magum unit
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system

    Adding solar panels to the set-up is easy: you just get enough panels and the right size charge controller. The panels feed the controller, the controller charges the batteries. It's pretty much independent of the inverter. If you plan it right you can even start out with a minimal solar array, then add more as $ permits. The problem here is that sometimes panels go out of production and then you have a hard time finding ones to match (says the guy who wishes Sharp hadn't stopped building the 175 Watt units before he had the money to buy four more).
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    what would you say is a good choice for panels that have been around and you antipcate being around for a while --iwas looking at 200-240 watt panels
    i could buy the Magnum with an epanel then add a charge controller when i need it --this maybe a simpliar system for me to work with and keep the cost down
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: newbie to solar--looking to install gridtie system

    I didn't mean to imply Sharp doesn't make panels anymore, they've just dropped all under 200 Watts.
    Kyocera has probably been around longer than most with fewer changes in panels or company.
    Most panels are of perfectly good quality if they have any sort of name attached. There was a local ad here recently offering some "no name" panels for a very low price, but they didn't say anything about warranty or certification. That's the sort of thing to stay away from.
    Otherwise it's a matter of matching up Vmp and Imp for later panel addition. Sometimes it takes a bit of thinking.
    When all else fails you can simply connect new panels with a new charge controller and avoid the issue altogether as the controller output will be based on battery bank Voltage. Although there you have to avoid low-end controllers which may not have the output specs needed to match the existing controller.

    Clear as mud?
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: newbie to solar--looking to install gridtie system
    ldiorio wrote: »
    this scenario is very interesting to me --maybe start with a Magnum unit to get 240 volts(for my well pump) and a 48volt battery backup Trojan L-16 RE-b with a gen switch

    with this plan how would i add solar panels( need panels and a charge controller)

    If you install the solar panels at the same time as the magnum, batteries, ePanel, etc, you will be eligible for 30% federal tax credits on everything but the generator. If you wait to install the panels you will be eligible for the tax credit on only the panels.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: newbie to solar--looking to install gridtie system

    With the Magnum you won't be able to grid tie unless you do an "AC coupled" system which is complicated and more expensive.

    I do what you are after with an Outback GVFX 3648. Running my 240 V 1 hp septic pump is easily and very efficiently done with an Outback PSX-240 autotransformer. I do have solar panels and sell to the grid but my system would work fine for short power outages without them. I'm very happy with my equipment and highly recommend Midnight CCs and ePanel.

    One issue you will run into with hybrid inverters is they generally want grid quality AC input from a generator. Outback says to only use inverter generators with their G inverters. I've heard the Xantrex XW inverters also do better with inverter gens.

    Now there's ways around this - with a transfer switch and a Midnite epanel you can easily bypass the inverter when you need to run loads from your large genset. You would want a stand alone battery charger for extended outages if you don't have enough PV.

    You could also simply use an Outback or Magnum non gridtie inverter that will take your gens input. This system would need to be switched on during grid outages.
  • ldiorio
    ldiorio Solar Expert Posts: 47 ✭✭
    Re: newbie to solar--looking to install gridtie system

    hi all
    has been a while since i was thinking of a solar system--since then have read lot of info on many systems and videos
    think i have decided on a Magnum 240/48 volt unit with e-panel--6-9 panels and trojan 16re batteries --my concern is a long term outage and can manually switch to my 10kw gen if need to charge the batteries on cloudy days
    i think the Radian is just too big of a unit for my plan
    in a long term outage this plan will help me minimize the use of my big genset
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: newbie to solar--looking to install gridtie system
    ldiorio wrote: »
    hi all
    has been a while since i was thinking of a solar system--since then have read lot of info on many systems and videos
    think i have decided on a Magnum 240/48 volt unit with e-panel--6-9 panels and trojan 16re batteries --my concern is a long term outage and can manually switch to my 10kw gen if need to charge the batteries on cloudy days
    i think the Radian is just too big of a unit for my plan
    in a long term outage this plan will help me minimize the use of my big genset
    That how it works, the Inverter will qualify the Generator Input, it will engage the transfer relay and the loads will switch to generator power ( Pass Through ) and the charger will start charging the batteries. When the Generator power is terminated, it will transfer back to the Inverter. It should be pretty much seamless as the power is synchronized.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: newbie to solar--looking to install gridtie system
    That how it works, the Inverter will qualify the Generator Input, it will engage the transfer relay and the loads will switch to generator power ( Pass Through ) and the charger will start charging the batteries. When the Generator power is terminated, it will transfer back to the Inverter. It should be pretty much seamless as the power is synchronized.

    Isn't there something strange/annoying about the magnum inverters regarding programming the max AC input IN for the built in charger in that it always pulls the max and then ramps DOWN rather than starting at the low end and ramping up; which cause some problems with tripping breakers on generators? I think I remember someone talking about this in the past.
    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
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: newbie to solar--looking to install gridtie system
    jcheil wrote: »
    Isn't there something strange/annoying about the magnum inverters regarding programming the max AC input IN for the built in charger in that it always pulls the max and then ramps DOWN rather than starting at the low end and ramping up; which cause some problems with tripping breakers on generators? I think I remember someone talking about this in the past.
    Yeah, kind of, It will overshoot the setting ( almost double ), then ramp back has been my experience. It's hard to tell if they are all that way or just that one model. With a 10KW generator he / they shouldn't have a issue, I wouldn't think.