questions about sw-4024 & T-240

solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
I have a few questions about xantrex SW-4024 inverter and the T-240 transformer. I am GTI now but want to add an offgrid system since I already have most components. Here is interlock system I want to install in service panel. http://www.interlockkit.com/ . ?#1 Will a T-240 transformer fed 120 from a SW-4024 inverter give you 240 vac with LI and L2 bieing 180 degree off phase same as normal power from power co? ?#2 If L1 and L2 has 180 degree phase as asked in question 1, will the 60 hz be stable enough for a GTI inverter to couple with it? ?#3 If all this works up to now Is a PWM controler good enough to use for a diversion load controler to a waterheater? I have a dc generator I plan to use in emergency to keep batterys charged if solar needs assistance. :Dsolarvic:D

Comments

  • Solar GuppySolar Guppy Posts: 1,959Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    The T-240 won't work as its not center tapped which is what is required for split-phase. You can run dedicated 240V loads, but not from the panel as the neutral is a code requirement

    Also, the SW is near extinction, if your thinking of buying one, don't. Even if they are free, the cost to fix a broken one is not worth the expense and hassle.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Thanks Solar Guppy for answering my question. I already have a SW-4024 that I bought a few years ago and never used. I also have an unused SW-6048. So guess I will just use the SW-4024 as a 110 volt inverter, unless I sell it. Since I am already old maybe the inverter will last as long as I need it. Is there a centertaped transformer that anyone can recomend me to use? :Dsolarvic:D
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    Perhaps you could use Outback's autotransformer: http://www.solar-electric.com/x-240.html
  • Solar GuppySolar Guppy Posts: 1,959Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    No, that's the same as the T-240 .... its a 2 to 1 transform, no center tap. To be clear, you can run 240V loads this way ... but you can't use it wired to a home breaker panel as its not center tapped, well to code anyways.

    If you have a xw-6048, use that. You can still sell the SW and get some decent dollars, anyone that has a dead SW would be easier to just replace with another SW

    Also, the SW isn't legal to use for gridtie, doesn't meet the current UL1741 requirements, so you can't have it sell to the grid. I know people still do though ...
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    I got the impression he was going off grid. It's common to use the X240 that way: hot to black, neutral to white. White tied to white creates central neutral that can be tied to ground. Red becomes second leg 120 VAC, with 240 VAC from black to red.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    To clarify what I am comtemplating. I want to install an interlock kit in my service panel http://www.interlockkit.com/ If you look at this website it shows what I want to do. One way you get the power from grid, other way you get power from offgrid inverter. This will give me a backup for all the power outages in my area. Had about 15 this year so far. The powerlines run thru the woods and the power co don,t keep the trees trimmed like they used to. Seems they just wait for the trees to fall on the powerline and then call the tree triming co. I have 2 dedicated GTI inverters that feed the grid thru my mobilehome outside service pole. The mains from the outside servicepanel has main breakers and service breakers that feed inside service main breaker in inside service panel. . With interlock kit I would have capability of grid and offgrid isolated from each other. On bright sunny days I would like to have my dedicated GTI inverters feed the grid to build up my power credit and have offgrid service my home. AT night I would connect back to grid and charge batterys from inverter charger or my generator if extended power outage. I want to AC couple my unused fronuis IG-2000 inverter with the output side of the T-240 transformer to my service panel when offgrid. So my main question was will the SW-4024 output acurate enough 60 cycle current thru the T-240 transformer for the GTI inverter to turn on. I already have the SW- 4024 (bought new by me and never used) and all other equipment except batterys and the interlock kit to do this. Since the life of an inverter is expected to be about 10 years, shouldn,t I just use the SW-4024 if I can instead of buying a newer inverter that is in production. seems like thier eficiency rating is as good as any new one on the market now. And with it bieing unused shouldn,t it still be usefull for the normal lifespan of an inverter. I will be 67 next birthday and if the inverter last 10 years and I am lucky enough to last as long I can buy another inverter then. After all the SW bashing I have heard here it would probably be preety hard to sell anyway. Yes I would like to have a new Magnum inverter MS-PAE 4024 inverter that would be lots easier to do the AC coupling I want to do. I did talk with a Magnum engineer and he told me I could do this with the MS-PAE inverter and wouldn,t need the T-240 transformer. He sent me the drawings.. :Dsolarvic:D
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    Just my opinion but ...
    So long as the "off grid" inverter is isolated from the grid at all times there should be no problem using it to provide 240 via a transformer. Just remember that the power will be cut in half on 240: you'll only have 2kW to work with and that won't run much (like an electric hot water heater).

    Basically you're treating the SW 4024 as an emergency back-up generator, not as a GT inverter with battery back-up.
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    P.S.: remember to isolate the SW's AC IN so it does not "back feed itself" when the SW is powering the panel. Otherwise it will click on and off repeatedly as it detects its own output as "AC present" and tries to switch loads to itself and charge from itself.
  • mikeomikeo Posts: 385Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    You could look at this listing and see if it works.
    http://www.ebay.com/itm/Hevi-Duty-5-KVA-Transformer-1-Phase-120-277-X-120-240-Volt-/270819018105?pt=BI_Circuit_Breakers_Transformers&hash=item3f0e124579

    I have a similar setup for backup power using SW4024 and an old 5 KVA GE transformer with 120/240 volt primaries and secondaries. I have paralleled the primary for 120 volts and series'ed the secondary for 240 volts using the center tap for neutral. This runs my 1/2 hp 240 well pump, lights, fridge, freezer for a couple of days or more depending on panel production. After that, I have to hook up my 13KW PTO generator to recharge the batteries for about 6 hours. During that time we can heat electric hot water, take a shower, cook a meal on the electric stove or what ever, then back to two more days of conserving. Usually the hot water lasts till gen is run again.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Thanks Mark and Mike for your encouragement. I thought it should work and I can make use of the equipment I have. My 240 loads are my 3/4 hp well sub pump and my Geospring waterheater. The economy of the waterheater impresses me. In 51 weeks it consumed 490 KWH, Probably do a post on it after the year is up. I want to connect my T-240 transformer and measure its power use with my Kill a watt meter. . I also have a exeltech 1100 inverter I plan on dedicating to my fridge and maybe the waterheater if I can. I have heard the waterheater uses about 700 watts when running.That won,t be connected to my service panel or anyway with the sw-4024 except battery. I think I might use Crown l-16 or maybe a forktruck battery. Kind of thinking A forktruck battery might last as long as long as me and should be easy to take care of. I will be using 14 or 15 Kyocera 158 g panels with my fronuis grid tied inverterin this setup. I used it 1 winter with 14 panels without overloading it. When summer came I had 16 panels. when fall came I thought it was overloaded slightly so transfered it out to a 600 volt inverter so I could use all the 16 panels I had. The main reasons i am increasing my power production is I want to make more use of my air conditioning and be prepared for an oxygen machine if needed. I worked in a foundry most of my life and that impairs your lung function. I just want to get set up while I am physicaly able to do it. Mike ,Think I will buy that transformer. If I decide I don,t need it, it won,t be too big a loss and Probably someone here might want it. :Dsolarvic:D
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    A couple of things to keep in mind:
    The water pump or the water heater might exceed the SW's capacity, causing a fault. Even just the two 120 legs could max it out; it's amazing how fast small loads add up!
    If you want to measure 240 VAC loads with the K-A-W you'll have to put it on the 120 VAC side of the transformer.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Mark, I thought I posted a reply to you but it doesn,t show so I will redo it. I was going to put a cord on the 110 side of the T-240 just to test the consumption of the waterheater. I probably will let the grid run the waterheater most of the time anyway. I picked up a manual interlock transfer switch that I can use on the waterheater. BB already estimated the power surge needed for my pump and would max out a 400 amp set of l-16 batterys. So when I get to the battery stage I will answer more questions. The 2 brands I was considering was US Battery or Crown. Neither distributor wants the old batterys. Crown said They give $3.00 for trade and said if I had any I could sell them at the salvage yard for more. Crown actually gave me a lower price than US battery. The deca battery distributor wants lots more money plus trade ins. :Dsolarvic:D
  • RCinFLARCinFLA Posts: 1,280Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    A T-240 is wired as an auto-transformer. As shown in manual, center tap is connected to neutral.

    It has no problem supplying 240/120v split phase output to a breaker panel, driven by a 120vac source.

    Just connect neutral center tap to neutral bus on breaker box and two hot L1 & L2 lines across 240 vac to main breaker supplying bus bars in breaker panel. Connect SW4024 neutral to neutral on transformer and ACout hot line to L1 connection on transformer. If you have statistically more 120vac loads on one leg then make that leg the L1 side of transformer as this is directly out of the SW4024 output and its leg's current will not be going through transformer. This is why a given wattage isolation transformer can supply twice the power when used as a auto-transformer wiring. You can think of the transformer as just reversing the phase of its input and supplying power to just the other phase. Down side of auto-transformer config is you lose isolation.

    You should have separate input breakers in breaker panel for its bus bars.

    Achieving startup surge for a 3/4 hp pump might be iffy on a SW4024. If pump has 120v wiring option you might at least try it supplied by 120v output of SW4024 before going to the trouble of wiring in the T-240 transformer. Also, my opinion on the T-240 is the 3900 VA spec (as auto-transformer) is a bit of a stretch for a 60 Hz transformer that weighs only about 35 lbs. It should be about 14 lbs. heavier for that VA spec.

    You will likely have trouble if you try to tie the GT inverter directly to output of T-240 transformer. If PV power ever exceeds your actual AC loads the SW4024 will trip off with an alarm for "AC input tied to output". You can do it if you manually assure the AC loads are consuming more then your maximum PV power generation. (like when you are running the pump)

    There is a chance the rather 'ratty' stair stepped sinewave from the SW4024 may not be liked by the GT inverter and it never engages. You also won't be able to charge the batteries from the GT inverter PV power.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Rc in florida I apreciate the advice. Do you think I might be better to get that transformer that Mikeo posted for me to buy? After reading the SW-manual a few times I am thinking the GT inverter might not turn on. So maybe I might have to change plans. 15 Kyocera 158-g solar panels (158 watt) I was going to use are presently wired and operating a Fronius 3.0 IG plus inverter. I have a new array with new higher watt panels I am going to switch the fronuis inverter too. So it looks like I have 2 choices, either buy a new high voltage scnieder charge controler and use my present SW-inverter or buy a new Magnum inverter that suports grid coupling and has 240 volt output. The extra fronuis inverter I was going to use only has 10 months use. Probably easier to sell it and put the money towards the the new charge controler I need. Actually getting the high voltage charge controler Is my preferred choice. I don,t want to export any electric from my offgrid setup anyway so the SW should serve me just fine. :Dsolarvic:D
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    GT only inverters do not play well with off-grid synch sources; there's no place for all the power to go and they will try to produce all the power they can. Several people here have tried this with MSW inverters, sine wave inverters, and generators. Lots of headaches and problems all based on the fact the equipment isn't meant to be used that way. The exception being the SMA stuff (Sunny Boy GTI's used with a Sunny Island battery inverter).

    You can take the SW off grid, but my advice would be don't try to couple it to grid-tie inverter(s) if you do.
  • mikeomikeo Posts: 385Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240
    So it looks like I have 2 choices, either buy a new high voltage scnieder charge controler and use my present SW-inverter or buy a new Magnum inverter that suports grid coupling and has 240 volt output
    If I understand you correctly, you have an all new system going in for grid tie. The older system, you could turn into a parallel off grid system if you can isolate your critical loads through a new wiring panel. Size your load to your battery system when you obtain it and run that section of your house as an off grid setup. Use the grid to charge your batteries when necessary and when the grid is out the critical loads continue to operate as usual. Does this make sense?
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Mikeo, The stuff I have I bought new in the 90,s and never used it. Went grid tye instead when Pa. updated thier laws that made GTI net metering more fair. Now I decided to try to use the stuff I have on hand for an offgrid system. We have lots of poweroutages here. I made an offer on the transformer on Ebay you told me about. Havn,t heard back yet. RC in Florida thinks the t-240 I have might not start my pump. I don,t want to feed any more to the grid and have to go thru another inspection. I decided to give up on ac coupling and buy one of those new high voltage controlers that schiener has. Since the panels I am going to use are alraddy wired for GT inverter. So I am goinf to put my fronuis inverter up for sale since I don,t need it now. It only has 10 months use. I have a exeltech 1100 inverter I will probably dedicate my freezer and fridge to. or maybe my geospring waterheater. After I run the test with my t-240 I will know if that will work. Seems like the waterheater uses about 500 kwh per year. On the 20th the first years use is up. So far used 492 kwh. I had the kit put in the exeltech that cuts the idle use to 10 per hour. I will use 15 or 16 kyocera 158g panels for battery charging and use grid for backup charging. Now I need to study up on that new charge controler to see what extra equipment I need to use it. :Dsolarvic:D
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: questions about sw-4024 & T-240

    The possible issue with the water heater isn't its 500 kW hour yearly consumption (which would be a battery issue) but how much power it draws when it runs. It could exceed either the SW's 4 kW rating and almost certainly the Exeltech's 1.1 kW rating. Just check on that. Otherwise it sounds like you're on the right track.

    Those Xantrex MPPT80-600 controllers are very expensive. With all the "accessories" it's in the $2,000 neighborhood. $1,250 just for the controller. I think it needs an additional display/programmer unit. It will do 24 or 48 VDC systems.
  • BB.BB. Posts: 27,352Super Moderators admin
    Re: questions about sw-4024 & T-240

    From what little I have read, if you put the Heat Pump type electric water heaters on Heat Pump Mode Only (no big electric element booster heat)--It only draws a few hundred watts (300-400 watts????) plus whatever the compressor starting surge may be.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Posts: 27,352Super Moderators admin
    Re: questions about sw-4024 & T-240

    From what little I have read, if you put the Heat Pump type electric water heaters on Heat Pump Mode Only (no big electric element booster heat)--It only draws a few hundred watts (300-400 watts????) plus whatever the compressor starting surge may be.

    Some brands may have an electric strip heater to defrost the external evaporator coil (need to check manuals--may have been older brands/models).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    BB As soon as my 1st year is up I am going to do a test with a t-240 with my koll o watt meter on the water heater. I have never run out of hot water and had it on the eco mode since day one. Mark, Don,t think I will have $2000.-00 in the big charge controler. I was reading the install manual and I can use the same disconnect I am using for my GT inverters. My disconnect is a 30 amp 3 phase disconnect and I have the 600 volt fuse in the combiner box near the panels. I will only have one string @ 7.58 short circuit amp. Controler here is $1245 and the display is about $295.00. So should be about $1600.00 including shipping. If I went with a midnight 150 controler cost $680, combiner box, another $100.00 Breakers for 4 arrays $50.00, big breaker for the controler. Another 100 ft ditch to dig plus conduit and and extra wire. So by the time i did all that extra work and have to buy components I don,t already have I wouldn,t save much. :Dsolarvic:D
  • VicVic Posts: 2,871Solar Expert ✭✭✭✭
    Re: questions about sw-4024 & T-240

    Vic,

    Unless you already have the FW Implanter "Tppl", you might well need to spend another $250-ish for it. As you know, the XW MPPT 600 80 is a new produce, and one might to need to install new FW from tine-to-time.

    And just make sure that the/any PV Disconnect is DC rated for 600 V.

    Good Luck, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Yes I have been using my 600vdc disconnect for nearly 2 years now. It has 3 legs and I still have an unused leg. It already passed inspection. The reason I never did the offgrid thing before was I let it scare me. This time I am not going to let me get discouraged. If I have to buy the firmware tool I will. Will be calling our host tomorrow to get the details. I never plan on more than one controler so shouldn,t have the hassle of trying to get it to work with other controlers. If you saw where I would have to dig a new ditch you would know why I don,t want to do it again. Had to have an excavater before and I would have more money doing a conventional controler than this expensive one. What little ditch I need to dig I will do by hand so should save money using the more expensive controler. Vic, Do you have one of these new controlers? :Dsolarvic:D
  • RCinFLARCinFLA Posts: 1,280Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240
    BB. wrote: »
    From what little I have read, if you put the Heat Pump type electric water heaters on Heat Pump Mode Only (no big electric element booster heat)--It only draws a few hundred watts (300-400 watts????) plus whatever the compressor starting surge may be.

    Some brands may have an electric strip heater to defrost the external evaporator coil (need to check manuals--may have been older brands/models).

    -Bill

    The good and bad about Heat Pump Hot water heaters.

    The comparison between manufacturers is a little difficult because there is no defined test standard.

    Energy factor is best there is at present but manufacturer stretch the true a bit.

    From GE spec sheets, its 50 gallon unit can recover 8 gallons per hour solely using heat pump with ambient temp of 68 degs F and hot water of 120 degs F running 550 watts of power.

    Just FYI, Average shower is 8 to 10 gallons of 120 deg water after diluted with cold water to get desired shower temp. So you can see there might be a recovery time issue if you have several people taking showers around the same time.

    For the 8 gallons of reheating data, this translates to a BTU/hour generation of 3,328 BTU's/hour rate, consuming 550 watt-hours.

    A 4500 watt electric element generates 15,365 BTU's per hour, consuming 4500 watt-hours.

    So, heat pump recovery is 4.6 times slower then electric element.

    Heat pump yields 6.05 BTU's per watt-hour.
    Electric element yields 3.414 BTU's per watt-hour.

    Efficiency factor would be 6.05/3.414 = 1.8 .

    Manufacturers claim 1.5 to 2.5 for EF. 1.5 would be using some electric element recovery assist. Numbers greater then 2 are using only heat pump and derating the insulation of typical electric element hot water heater, by as much as 20% heating loss. They put more insulation on hybrid heat pump units.
  • VicVic Posts: 2,871Solar Expert ✭✭✭✭
    Re: questions about sw-4024 & T-240

    Vic,

    Great that your Disconnect is DC rated.

    I did look at the X/S 600 V (max) CC, but given that it is without a front panel (WOW, it DOES have several LED'd), It has no built-in mechanism to implant new Firmware -- both essential items to me, and it needed just a bit more output current capability, I passed on it.

    I STILL have that sour taste in my mouth from my purchase of the predecessor CC, the Xantrex XW SCC-150 (#?). It did come with horribly FLAWED, BUGGY FW. Neither the seller nor Xantrex would take it back to do the update, even though the FW was stale when I purchased the unit -- It did not know what charge state it was in. There may have been other BUGs, but tossed it upon finding that one.

    Will never be able to forget this. Have told this story couple of times here, so will leave it at that.

    Just want to let others know that the $250.00 doodad is required to implant FW, and unlike OB Power, X/Schneider will NOT do it -- even if it is disfunctional.

    Good Luck, and for you guys with GT arrays, the new X/S CC seems to provide good functionality, especially if it happens to work!

    Good Luck, another Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • solarvicsolarvic Posts: 1,045Solar Expert ✭✭✭
    Re: questions about sw-4024 & T-240

    Yes I am not all that crazy about Xantrex either. I bought my sw-4024 so I could be grid connected and they come out with the GTI interface. so I was saving for one and they quit making them and I couldn,t get one. That is kind like a car you buy and 5 years later you can,t get tires for it because they updated them and no longer make your size. I know I am not going to dig that ditch again I was talking about in previous post. I have all my solar panels south of my garage and can,t add anymore there because if shading. I have a Fronius 30.1 plus inverter connected to 16 158 watt solar panels there. What I am doing is adding 16 more solar panels north of my house at least 210 ft. And planned on locating 8 185 watt and 8 180 w panels and abandoning the 158 watt panels for my offgrid system. Since everything is wired for high voltage I can,t use a regular charge controler on the 158 watt panels. Why I am just about forced to get the high voltage controler. Another posability is I could move all the 158 watt panels to the new location and just put my new higher watt panels where the the 158 watt panels are now. The old and new panels are kyocera and have the same bolt pattern. Width is the same .only difference is the newer ines are a little longey over all and thicker. If I did that I probably could use the midnight controler. Guess I will have to check out that tool midnight has. I do have a 500 ft roll of #2 aluminum burial wire I could use. Thats enough to get to the controler. Glad you pointed that out about all the software problems. Switching those panels on the racks would be a lot easier than trying to change the wireing,digging ditches, ect. :Dsolarvic:D
  • VicVic Posts: 2,871Solar Expert ✭✭✭✭
    Re: questions about sw-4024 & T-240

    Vic,

    Sounds like your system is ideal for the XW MPPT600 80 (is that the#?). Good luck with it. This HV CCC would have saved a lot of conduit and wire/giblets in my system. But, would have needed two of them, so the economics (if nothing else) just did not work out.

    I rag on Schneider a bit, for their (lack of) customer service. Seems that almost the only thing that matters to them is SELLING porduct. Once YOU own it, they seem to care very little.

    Altho, have been very happy with the old Xantrex SW+ 5548s. Solid after six years ... knock, knock.

    Have fun, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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