few questions parallel PV wiring, MSW inverters..

notsobrightnotsobright Solar Expert Posts: 247 ✭✭
Im getting ready to wire in my new KC130.

I will be wiring 3 panels in parallel to stay 12v. I have the KC130 and two KC40s

1) does the position in the array matter for where the larger panel is located?

2) it seems I will need to install larger fuses in the middle and first panel but then they will exceed the panels rating. I must be missing something here but what is it?


3) what is the most reliable 1800 - 2000 watt Modified Sine Wave inverter? I now have the suresine 300 for delicate electronics but I owuld like to get a larger inverter for the other stuff.

4) is there a definate electronics "do not use on MSW inverter" list or probable equipment that will have issues/malfunctions?


thanks

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    MSW causes trouble with quite a number of things, most notably; AC induction motors, radio frequency devices, audio-visual equipment, battery chargers. Sometimes this is because the waveform is too "noisy" and sometimes it's because the voltage "appears" low. These are both characteristics of MSW. How well a particular thing works on MSW is dependent on the device. Recently some tool companies have introduce rechargers that will work with MSW. Most of them do not.

    What kind of budget do you have? Maybe you should consider something like this:
    http://store.solar-electric.com/sa15wa12vosi.html

    Double-check with the experts here, but I don't think you need three separate fuses on your array. There's not a big difference between a 130 and a 140 so they should be fine in parallel.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    i'd fuse each pv individually and if they have junction boxes then that's the best place for it. sometimes a fuse for each pv at the pv would be inconvenient to reach should it ever blow so they should at least be at the first accessible point, but before being combined. case in point was were we had a poster chime in that he accidentally wired one of his paralleled pvs in backwards. without a fuse the full brunt of all of the pvs is now in a short circuit condition and it blew out the pv he wired backwards as it was handling the power of all of his other pvs through it.
  • notsobrightnotsobright Solar Expert Posts: 247 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    actually Im looking for recomendations on Modified Sine Wave inverters. I just got this SuneSine300 two weeks ago so I would like to have a MSW in the 1500+ watt range to go along with it. seems reliable and quality arnt associated with MSW Inverters but there has to be some that are better than others.


    I will have a fuse in each junction box on each panel but the way Im understanding the wiring in parallel is that the first panel that is closest to the controller the fuse would have to be high enough amp rating to handle the output of all three panels and if it is then it would be a higher amp rating than that first single panel requires. I need to find a good sample diagram for parallels.

    and would the 130 watt panel be best wired in closest to the controller or farthest if the other two panels are 40 watt each?


    thanks
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    Size the fuses for the panels. Which one is 'first' or 'last' doesn't really matter with a parallel connection. I think you may be confused as to where the fuses go in this sort of hook-up.

    Panel -> Fuse -> Junction -> Charge Controller

    The only thing going through the fuse is the output from the one panel.
    Unless, as Niel pointed out, somebody wires something backwards and it tries to send the output of two panels through the third. In that case the fuse on the third panel blows and protects it from the other two.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    as an option you could fuse the output of the combiner to the cc and that value would need to be that of all combined. short circuit current x 1.25 and round up to closest commercially available value.
  • notsobrightnotsobright Solar Expert Posts: 247 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    I think the "combiners" are what is throwing me off.


    could it be as simple as: (fuses omitted)

    one wire connected to three wires, the one wire goes to charge controller, each of the three wires goes to a panel.


    and still looking for MSW suggestions.

    thanks
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    MSW inverters from our wonderful host NAWS:

    http://store.solar-electric.com/maenmosiwain.html

    http://store.solar-electric.com/xatrsemosiwa.html

    Now look at the prices and compare them to these PSW from NAWS:

    http://store.solar-electric.com/sasiwain1.html

    You sure you still want MSW with its inferior waveform and associated troubles?
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: few questions parallel PV wiring, MSW inverters..

    I will add the caviet that those MSW inveters from NAWS are very nice MSW inverters...

    There are other MSW's that are probably 1/10th the price.

    For NSB,

    Read the following FAQ's from NAWS on the TSW/MSW issues.

    All About Inverters
    Choosing an inverter for water pumping

    Is there a list of what will or won't work on MSW inverters... It is the old 80/20 or 90/10 rule... 80-90% of the stuff will work OK on MSW, and 10-20% will not.

    Problem is that you will have to test (and possibly damage or long term life reduction of) your own equipment to find out.

    Things that tend not to work well on MSW can include; inexpensive wall warts (transformers, DC converters), small transformer devices (desk lamps tranformers), some electronics may not work well (TV, stereo, radios may have noisy pic/sound), some electronics may fail (internal power supplies overheat). Purpose built electric motors (small motors, low cost) such as refrigerator motors (motor uses ~20-25% or so more power because of MSW wave form--so motors/appliances run hotter--may overheat or die sooner because of heat), some battery chargers may instantly die--others will work fine, etc.

    That said, I have seen old color TV's work just fine (1982 Sony), universal motors (i.e., electric drills with brushed motors), motors that are not running near 100% of designed load (some people run well pumps just fine on MSW). More modern electronic devices that have Power Factor Corrected power supplies (I have newer laptops with PFC corrected supplies that should work fine, but older laptop and portable DVD player with wall wart that overheat on MSW--but I just bought a brand new 10" netbook computer that has a non-PFC AC supply--I would suspect that it would overheat too).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • notsobrightnotsobright Solar Expert Posts: 247 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    I did not realize that MSW inverters could be that pricey! kinda puts that idea on the back burner since its just something I wanted to have "just in case" Im sure my new suresine 300 will provide me with the ac power I need in most cases anyway. so how can the manufacturers justify those kinds of prices for MSW when they are inferior equipment?


    so then does my parallel wiring assumtion make sense? Im just trying to understand how to wire them together.


    my example, just the positive side with fusses omitted:

    one wire connected to three wires, the one wire goes to charge controller, each of the three wires goes to a panel. a simple yes or no will help me tremendously right here.

    I think thats correct but I just want to be certain. I cant seem to find a diagram that indicates exactly what I need to know or Im interpreting them incorrectly.


    thanks
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    You can buy cheap MSW inverters - and you get a cheap MSW inverter.
    I personally tested three from one of these "low dollar" companies when I was looking for one. NONE of them were capable of their rated output, much less surge capacity. They simply went into fault mode and shut down. Maybe if you added 100 Watts at a time ... Short version; cheap ones are more likely to be a problem than a help.

    You seem to have the panel connection figured out: each panel has two wires, (+) and (-). The (-) all connect together and go to the (-) "downlead" to the charge controller (which must be heavy enough to take the current from all panels combined over the distance). The (+) wires from the panel go through individual fuses (if necessary) then all connect together and go to the (+) "downlead". Alternately they are fused for full capacity after combining - check Niel or Bill's judgment on this, not mine!
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    If anyone is actually experiencing issues using a MSW inverter with a specific piece of equipment, I'd like to hear about it. I've been using MSW inverters since the mid 90s, and it's very rare for me to find any equipment that doesn't work just fine.

    Some examples:

    chair3.jpg

    There's $100K worth of sensitive equipment in the base of this research chair, all running on MSW power. Any RF noise would trash our ECG and Cranial Doppler signals.

    http://www.2manytoyz.com/hardware/inverter/inverterlaptop.jpg

    I've used my personal laptop with a MSW inverter for the past 4 years. Even longer with the computers at work.

    6477.jpg
    6446.jpg
    6479.jpg

    I operated the garage door opener with it. There was no noticeable difference in performance than when the opener is connected to the grid.

    http://www.2manytoyz.com/hardware/inverter/vaninverter.jpg

    I've run LOTS of equipment for over a decade on MSW inverters. If you check the waveform of most UPS units, those are MSW. Some are even squarewave.

    All that said, the prices of True Sine Wave inverters has fallen drastically. Xantrex has come out with a new series of inverters that only cost $479 for a 2000 Watt model: http://www.campingworld.com/shopping/item/prowatt-sw-inverter-2000w/47751 I paid about $300 (on sale) for my 1500 Watt MSW back in 1995.
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    As for some cheap inverters not being capable of supplying the rated output, may well be true, but not true in all cases.

    vectorsale1.jpg


    dsc_0074.jpg

    dsc_0076.jpg

    dsc_0077.jpg

    Rated at 400 Watts. Loaded with a 320 Watt solder pot, and a 60 Watt soldering iron. Let it run until the solder pot was molten.

    I have to say I'm very impressed with the Vector brand inverters. I am running my living room lighting (CFL) from one of these every evening. I have another one of these running my outdoor lighting (also CFL) from dusk to dawn every night.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    Point made, 2manytoyz.

    But ...

    None of the equipment you cite is anything I'd expect to experience trouble on MSW. "Sensitive equipment" invariably has really good power supplies. It's usually the "el cheapo" electronics that pick up noise or otherwise don't function.

    I had a 3kW Xantrex MSW before. It would not properly operate my cordless tool battery charger, it put noise in a cheap radio (but not the Sony), wouldn't run the water pump at all despite being almost 3X the capacity, and caused the UPS on the computer to go into fault so often it was useless. Refrigerator motor "clattered" when starting too; hard to get it ramped up to speed.

    Which just goes to show it's a hit-or-miss proposition in getting an MSW to work with the particular equipment you have. Some of them definitely have "cleaner" signals than others (more "steps").

    Frankly, my old Statpower worked better than the Xantrex in some ways, but just didn't have enough Watts for the things I have to run. And when the Xantrex starting going "low voltage" every time the cooling fan came on, the company wasn't interested in discussing the matter at all. I hope they've improved on that because they make a lot of really good equipment, but if it isn't backed with service it's not so good.
  • notsobrightnotsobright Solar Expert Posts: 247 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    what the heck sits in that chair? wow, really wish I had known about that 2000w one a month ago.

    I have experienced issues with a small 200w MSW inverter with my laptop. I was using a usb card reader with SD flash memory cards transferring photos I had shot and lost them all a few times and toasted three SD cards (all different brands) before someone pointed out to me the Flash memory cards dont work well with inverters. this was before I got into this solar stuff. thats the only issues Ive had though.


    I guess thats a "yes" Cariboocoot?

    gotta coupla more questions...

    1) is it nessasary to ground the panel frames in an RV installation (no grounding rod, just chassis ground) mabey in this case its better NOT to ground them..

    2) where would I find #10 twin lead outdoor/weather proof connectors?

    I'd like to be able to quick dissconnect my panels and relocate them occassionaly but cant find a suitable connector. I like whats found in automobile wirring harnesses but dont know where to find them.

    thanks
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    what the heck sits in that chair? wow, really wish I had known about that 2000w one a month ago.

    The new series of Xantrex Pure Sine Wave inverters just came out. Doesn't have all the features of the Prosine series, but heck of a deal for the price.

    The chair was used on a motion sickness study. Long story, but enough to say some did get sick! Medications were used to mitigate the symptoms.
  • 2manytoyz2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    Point made, 2manytoyz.

    But ...

    None of the equipment you cite is anything I'd expect to experience trouble on MSW. "Sensitive equipment" invariably has really good power supplies. It's usually the "el cheapo" electronics that pick up noise or otherwise don't function.


    Examples of el-cheapo electronics: laptop computers, portable radio scanners, CFL lighting, variable speed Makita drill, variable speed Dremel Moto-Tool, various power supplies.

    dremel_inverter.jpg

    dscn3122-t.jpg

    RF noise would also likely trash data from the cranial doppler, the RF spectrum analyzer, any of our comm gear, telemetry equipment, an HCL monitor/transceiver, or with vibration anaylsis gear.


    fieldpower1.jpg

    m113power.jpg

    Just so we're clear, I'm NOT saying MSW won't trash part of the RF spectrum (some tear up the AM band in particular), or prevent variable speed equipment from working, or even some motors from starting.

    It is a crap shoot. But in my experience (rather broad as the pics show), odds are better than not, that MSW inverters will do the job just fine. There are NO guarantees for sure. And now that PSW inverters are way down in price, I would recommend considering buying a PSW instead.

    I often get told "that won't work" whenever I discuss my experiences. There's a fair amount of armchair quarterbacking on the net. So this is why I was asking for specific examples, which a couple of you provided, thank you. That's useful information! Nothing about inverters is absolute.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    2manytoyz wrote: »
    Examples of el-cheapo electronics: laptop computers, portable radio scanners, CFL lighting, variable speed Makita drill, variable speed Dremel Moto-Tool, various power supplies.

    Just so we're clear, I'm NOT saying MSW won't trash part of the RF spectrum (some tear up the AM band in particular), or prevent variable speed equipment from working, or even some motors from starting.

    It is a crap shoot. But in my experience (rather broad as the pics show), odds are better than not, that MSW inverters will do the job just fine. There are NO guarantees for sure. And now that PSW inverters are way down in price, I would recommend considering buying a PSW instead.

    I often get told "that won't work" whenever I discuss my experiences. There's a fair amount of armchair quarterbacking on the net. So this is why I was asking for specific examples, which a couple of you provided, thank you. That's useful information! Nothing about inverters is absolute.

    I often get told the same thing. :)

    If anything, together we have just proved the point about MSW: sometimes it will, sometimes it won't. Hard to know in advance, eh? :) Although the quality of the inverter and the equipment is probably a big factor. Inexpensive doesn't necessarily mean "el cheapo", btw. :p
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..

    Just another two cents worth:

    Having live for a over a decade on a Heart Interface MSW 2000w inverter the only thing that "fried" was a portable tool battery charger that I'd borrowed, but upon inspection I was able to repair (too many years ago to remember details).

    Our microwave worked better when we got a true sine wave inverter (Magnum).

    I'm still trying to figure out a use for that old inverter.

    Phil
  • dwhdwh Solar Expert Posts: 1,341 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    2manytoyz wrote: »
    Long story, but enough to say some did get sick!

    That's easy! I and some partners prototyped and built a computer gaming network back in the mid-90's. The chairs we used were Thunderseats with built-in sub-woofers:

    http://www.project777.com/?etxsid=-1&pid=3767

    The systems also had CyberMaxx HMDs:

    http://www.zardoz.net/technology/cybermaxx/


    With either Falcon 3.0, or DOOM 1 we had quite a few people end up tossing cookies (especially at the first E3 where we publically demoed the system). Didn't even need real motion!

    http://www.youtube.com/watch?v=kf4oaUZMpFw
    (start at 1m 45s in)

    http://www.youtube.com/watch?v=ggMsQc9ld9g
  • notsobrightnotsobright Solar Expert Posts: 247 ✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    PhilS wrote: »
    Just another two cents worth:

    Having live for a over a decade on a Heart Interface MSW 2000w inverter the only thing that "fried" was a portable tool battery charger that I'd borrowed, but upon inspection I was able to repair (too many years ago to remember details).

    Our microwave worked better when we got a true sine wave inverter (Magnum).

    I'm still trying to figure out a use for that old inverter.

    Phil

    I heard the Dewalt chargers were going bad with MSW inverters so I bought one of their 12v to 18v chargers then after that I found out they fixed the issues with their 120vac chargers so they can deal with MSW input. figures.. I guess the 12v charger might be more efficient though but I dont know how to check that.



    I'll figure out a use for the old MSW you have. its probably alot larger than todays units, no? if you could part with it let me know.
  • PhilSPhilS Solar Expert Posts: 370 ✭✭✭
    Re: few questions parallel PV wiring, MSW inverters..
    I'll figure out a use for the old MSW you have. its probably alot larger than todays units, no? if you could part with it let me know.

    PM comin' at you.

    Phil
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