more help for types of installations

ZedicusZedicus Registered Users Posts: 13
i am again revisiting the possibility of solar to help reduce my homes strain on the grid. i will not be able to do a full grid tie with battery system. i cannot even fathom the size of a system that it would take. but i would like the best of both worlds. is there a such thing as a grid tie non battery but with backup generator system? so that when the power went off (not if, where i live it is a regular occurrence. a couple months ago we were with out power for almost 24 hours and my UPS system only runs for about 12 hours on my core network. edge stuff only made it 3 hours) what i am thinking is that when the grid goes down the generator kicks on and i get power from some solar panels and the generator. then when the grid comes up i get power from the grid and the solar panels.

does this exist or am i dreaming?

thanks again for the help

(if you guys check out my other post form about this time a year ago my power usage has gone up considerably again like i feared it would, and it was bordering astronomical then. i did and have done lots to lessen the usage but there is a home based business there and i am limited on options. i have even already converted to mostly LED lighting. i have a few timers in place with more on the way. hard power switches on lots of devices. )

Comments

  • solar_davesolar_dave Solar Expert Posts: 2,343 ✭✭✭✭
    Re: more help for types of installations

    Without batteries I think you are just going to get either or in a outage situation. A simple transfer switch for outages to fire up the generator is probably your best bet. Then just use a standard grid tie setup the rest of the time.
  • BB.BB. Super Moderators, Administrators Posts: 29,482 admin
    Re: more help for types of installations

    There is the SMA "-TL" option--But that only can output ~1,500 Watts at 120 VAC (for US versions) in the middle of a sunny day. And, as I understand, requires you to manually "turn on" the AC output.

    You could put a battery charger on the AC output to help your own battery backup--But it does not sound much like a practical solution.

    Otherwise, you could look at a set of switches to transfer (part) of your AC GT Solar Array to a standard Off Grid MPPT type solar charge controller--But this is not always a practical solution (GT solar arrays are typically a much different configuration that that use for most MPPT solar charge controllers).

    You probably would be better off going with a backup genset.

    More or less, if you have short/random outages of less than 1 week--And can store fuel (or use natural gas)--Genset

    If you have ~1 month outages once a year or so--perhaps solar+generator

    If you are planning on more than 1 month outages, then hybrid solar (off grid/grid tied inverter+batteries+solar panels+backup genset) is probably a good solution.

    If your business relies on computers and reliable communications, you may need to look at a hosting service. In general, while you may get a week or more of hardwired telephone service during a power outage... Cable, fiber, cell phones, etc. typically either die in a power outage, or only have a hand full of hours of battery/local generator backup. So, even if you can keep your critical systems running, your communications to the outside world may not.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: more help for types of installations

    It depends on how you look at it.

    There's no reason you can't do a standard GT system that has no battery back-up and add a generator back-up system as well. It will of course not make use of the solar in an outage.

    You can also add a small battery-based back-up system entirely separate from the GT system, with some options for recharging the batteries including possible AC coupling if you pick the right inverter.

    And there's the limited back-up of the no-battery SMA units with the Standby Power System http://www.solar-electric.com/inverters-controllers-accessories/gridtiesolar/sma-sunnyboy-grid-tie-inverters/sma-sunny-boy-transformerless-inverters.html which offer a limited amount of (manual) back-up power without batteries but only when the sun shines on the array.

    On the whole you have to figure out where you're at and where you want to be and try to work out a plan that will get you there without having to do everything over each step of the way.
  • ZedicusZedicus Registered Users Posts: 13
    Re: more help for types of installations

    yeah i do not in any way plan on running the entire facility on an 'off grid' solution. the longest outage i have seen in 10 years has been about 24 hours. harsh conditions out here make it so the electric company really does prepare for the worst. what i would like is to be able to have enough electricity to run a space heater, tv, computer, and maybe a toaster oven. during said outage so that the people on site don't die of boredom. (telecoms out here can stay up a long time, they plan for power issues as well)

    if i did a smallish battery+grid tie system then i could wire the breaker box to control what outlets stayed up when the grid went down and try to get a system that is battery + grid tie but not a system that is so big it would be trying to power the entire facility. i guess that seems plausible and is probably a more common way of adding a system to an already built structure.

    am i thinking in the correct direction or talking babble again?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: more help for types of installations

    Ooh no good.

    Space heater? Toaster oven? Big Watts and big Watt hours. Think 1500 each for an upper limit. Even at 500 Watts over time it will be a tremendous amount of power: 500 Watt low setting on a small oil-filled radiator running 1/3 on 2/3 off for 24 hours: 4kW hours, and you probably wouldn't even be very warm.

    Get a Kill-A-Watt meter. Plug in the TV, watch a show. Do the same for the computer and anything else you want to run. You'll get a good idea of how much power things really use, and might even find some things that can be reduced and save electric all the time.

    When I think of outages I think of keeping refrigeration going, so the food doesn't spoil. A freezer will generally stay cold enough for days if unopened, but a refrigerator is something you live out of and it doesn't take long before the internal temperature rises above bacteria-breeding level.

    Otherwise the re-wiring is about right: branch off essential circuits so they can be fed during the outage. This can be as simple as an extension cord in a pinch; I just run one out the door to the gen when needed here. So far that has been once when I actually used the gen; the second time the power came back before I had the back-up in place!
  • ZedicusZedicus Registered Users Posts: 13
    Re: more help for types of installations

    actually it would probably be less wattage to run the home furnace. it is gas for heat and only uses electricity for the igniter , blower motor, and thermostat. all of my telecom gear is about 200 watt running full tilt (most of the time its not at max but for the sake of a guestamate) the computers are low power custom built single purpose devices if memory serves i built them around 60 watt power supplys, and there's 2 of them. the TV i would have to meter to get an estimate i couldn't even guess. that said i would like to overshoot this by a fair amount.

    i guess my question is on the solar market right now is there a 'sweet spot' where pricing goes from average to high but performance does not maintain. like in LCD T.V. market up to around 60" its under 1000$ but then 70"+ the prices jump another 1000$ or more. is there a 'best wattage range for the cost' and are there brands that 100% should be avoided? i am in an area that specializes in WIND energy but i can not add a dedicated wind system in city limits ( there are small exemptions but nothing i am going to pursue) so finding vendors and installers of solar stuff is not an option. i can have a contractor install stuff, but odds are even that i will be doing myself. (besides the breaker box probably)
  • PhotowhitPhotowhit Solar Expert Posts: 4,994 ✭✭✭✭
    Re: more help for types of installations

    Shipping costs are quite large, so pallet quantities are typically the 'cheap' prices you see listed, before shipping... If you buy pallet quantities, their is very little handling of the product for the seller so less expensive. ...but a pallet of large panels runs from about 3400 watts up to 6000 watts of panels... Sometime 2 people will get together to buy a single pallet or 2 single point drop shipping saves money as well.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: more help for types of installations

    Unfortunately solar systems aren't one piece of equipment like a TV. What's more, your 'best deal' is going to depend on where you are. As Photowhit said panel shipping can be expensive, so can battery shipping. So the 'best price' has to be at your door otherwise panels at $0.78 per Watt can end up costing more than panels at $1.20 per Watt.

    As a rule, the venerable GC2 FLA's are the cheapest per Watt hour batteries you can get due to high manufacturing volume and widespread availability.

    Outback FM60 can be a great deal on a charge controller (same price as a Classic 150 Lite but has a display) but may not have the features you need.

    Nothing is a bargain if it doesn't suit your needs (as so many have found out from buying 'great deals' only to discover the stuff wouldn't work without some major engineering work and further expense).
  • PhotowhitPhotowhit Solar Expert Posts: 4,994 ✭✭✭✭
    Re: more help for types of installations

    ...to expand on 'Coot. When looking at system prices, keep two conflicting things in mind, often maxing out your charge controllers for your needs will be the least expensive... but leaving room for expansion when is often the best value.

    Higher voltage systems can often be 'cheaper' since charge controllers are amperage based, an FM60 could handle roughly 850 watts of panels at 12 volts, will handle 2x that at 24 volts and 4x (12 volt system) at 48 volts. Also wiring in higher voltage system will be cheaper, since wires are sized for the amperage carried, not voltage.

    Inverters, on the other hand, are voltage based, so can't be upgraded to a higher voltage system. So if you are close and not sure if you should have a large 12 volt system or a small 24 volt system... Often it would be in your best interest to go with the higher voltage system, since the inverter will be one of the more expensive items that usually can't be upgraded (some can be stacked for higher wattage output but at the same voltage)
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • ZedicusZedicus Registered Users Posts: 13
    Re: more help for types of installations

    are sealed or unsealed AGM batteries more common? i run sealed in my UPS arrays and i can probably build a bank of them for for dirt cheap.

    i probably have a spare 12v 1000 watt inverter from a previous UPS install that i could start a build with but the inspectors tend to frown on my home made looking devices. my plan would be to grid tie so i would need the products to be certified. if i am buying an inverter i can't imagine not going with at least 28v, and i would probably go 48v right out the gate unless cost was hugely different.

    i am starting to see that charge controllers and inverters are 'sold separate' devices. often times in the UPS world they are combined into one 'UPS manager" and sold based on KVA and then you have to apply math and more geustimations to get to real world estimates.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: more help for types of installations

    All AGM batteries are sealed, or more correctly valve regulated. They have the bare minimum amount of electrolyte in them to work. They cost more than flooded cells and don't last as long (especially if you make a mistake which is easy with AGM) but have certain advantages in current ability and no fumes/misting.

    Your 12 Volt 1kW inverter is a no-go on grid connection of course; it won't sync because it's not meant to. 12 Volt system in general aren't too practical and should really only be used where the 12 VDC is a necessity (as in mobile applications where the vehicle is 12 Volt). 24 Volt systems have a broad range of applications, but when the power need goes up so should the system Voltage. Then you are buying breakers specifically for solar because so much of the fuse/disconnects/breakers available will not handle the 60+ Volts found on 48 Volt systems.

    Anything grid-tied is going to have to be all certified and approved and installed with plans and permits.

    The reason for the separate entities in solar is flexibility. No two systems are really alike, so it helps if you can tailor the components to the application. With a UPS it's pretty straightforward: unlimited 120 VAC input and maximum Volt Amps output of 'X'; no variations in stored power, charging availability, load demand fluctuations, etc.
  • ZedicusZedicus Registered Users Posts: 13
    Re: more help for types of installations

    well not really. large UPS installs (think a closet with racks and battery trays) are not an 'off the shelf' situation either.

    so i will need a separate fuse (breaker?) system for the battery and panel array before it even gets to the house breaker box.

    the city will have to do the tie in and mount the separate meter that calculates my send back amount but that is all the city will touch. i wish there was a demo facility that did this stuff that i could at least look at. maybe Wichita has something like that.

    is romex standard wire for panels or something else?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: more help for types of installations
    Zedicus wrote: »
    well not really. large UPS installs (think a closet with racks and battery trays) are not an 'off the shelf' situation either.

    Actually they are: you just tell them how much power you want to supply and for how long. The rest is easy because there's that unlimited grid for recharging from.
    so i will need a separate fuse (breaker?) system for the battery and panel array before it even gets to the house breaker box.

    There will be several over-current protection devices in such a system. Exactly how many, what type, and where depends on the final configuration. The AC connection between inverter output and distribution panel may/may not have a breaker on it, but there will be some type of transfer switch (often built in to the inverter) to change over the AC source when the power goes down.

    On the DC side expect a fuse/breaker between the batteries and inverter and another between the charge controller output and the batteries. When it comes to the array it will depend on the configuration: PV being self-limiting in current makes the placement of OCP devices a bit different.
    the city will have to do the tie in and mount the separate meter that calculates my send back amount but that is all the city will touch. i wish there was a demo facility that did this stuff that i could at least look at. maybe Wichita has something like that.

    Now you are talking about a line-side tap with separate meter to measure the GT output to the grid, some of which may come back to the house 'immediately'. This is not a bad way to do GT installs, but it can't be used for back-up power; it is a configuration for standard GT systems only. Normally your AHJ will want to inspect ALL the wiring in the place. That's not the same as saying he'll understand it, though.
    is romex standard wire for panels or something else?

    It depends on where the wiring is. Standard wiring (Romex is a tradename) can not be exposed to the elements. So from the panels to the combiner it will be 'PV wire': basically 10 AWG with weather & UV resistant insulation and MC4 connectors at least at the panel end. If conduit is used after the combiner then standard wire may be used there. I hate to sound like I'm ducking the issue but again this is an areas where local authorities have the final say: what works electrically and what meets code approval are not always the same thing.
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