Any advantage of having multiple inverters?

[josefaz]

If I have the space, is having two (3000x2) instead of one (6000) inverter better? Thanks

[Mike90250]

Is this for grid tie, or off grid ? For grid tie, I'd use one, save the space and expense. For off-grid, I'd use 2, and you have a spare if one died.

[epsgunner]

Almost the same boat.. I have 870 watts (in 6- 12v rated panels..) and can go with 12 or 24v..

The downside (for me) is the 2K pure sine inverters for 24v are almost double the 12v options..

Growing a 24v bank is hard to do as well IMHO.. granted you use half the amps so maybe the bank would be the same 'size' at the end of the day.. 220 ah = 440 ah 12v (using 6v 220 ah batteries in example)..

I could buy 2 Xantrex SW Prowatt 2000 for $340 each.. or buy 1 Samlex SA-2000K-125 for $750ish..

I'm going to be off grid.. wondering if I need a spare or not??

I have 3/0 wire for the battery already here.. so the WIRE issue is muted already for me..

[AZstars]

Another one - me - in the same boat. Trying to ask SP for dual PowerOne 6.0 instead of 11.7 SMA/Fronius. Will listen to the replies here..

[KRenn]

If I have the space, is having two (3000x2) instead of one (6000) inverter better? Thanks

One inverter means cloud cover or sufficient amounts if dirt shutdown the system, two inverters divides that up and allows for better sustained performance, even moreso if you have dual-MPPT technology such as with Power-One or Kaco which has two ports that run into the inverter, further reducing the effects of dirt, cloud cover or shading. Two inverters will almost always cost more but there's definitely benefits to be had IMO.

[inetdog]

One inverter means cloud cover or sufficient amounts if dirt shutdown the system, two inverters divides that up and allows for better sustained performance, even moreso if you have dual-MPPT technology such as with Power-One or Kaco which has two ports that run into the inverter, further reducing the effects of dirt, cloud cover or shading. Two inverters will almost always cost more but there's definitely benefits to be had IMO.

Are you talking about grid-tie inverters or off-grid charge controllers?

For grid-tie, two inverters will usually sync just fine without interference, but for off-grid using two inverters to power one large load requires that they be designed to coordinate with each other. Even if you use them as two legs of a 240 volt supply, they will not work for 240 volt loads unless they stay rigidly in phase with each other.

[KRenn]

Are you talking about grid-tie inverters or off-grid charge controllers?

For grid-tie, two inverters will usually sync just fine without interference, but for off-grid using two inverters to power one large load requires that they be designed to coordinate with each other. Even if you use them as two legs of a 240 volt supply, they will not work for 240 volt loads unless they stay rigidly in phase with each other.

Grid-tied, definitely.

[Naptown]

Another one - me - in the same boat. Trying to ask SP for dual PowerOne 6.0 instead of 11.7 SMA/Fronius. Will listen to the replies here..

If the array is all at the same tilt, azimuth and no shading issues use the Fronius IG+
And here is the reason
The IG+ is essentially a three stage inverter. meaning it is broken up into essentially 3 4K inverters. Since inverters like to be loaded up to get the most efficiency out of them, other than during the peak hours of the day the inverter will be luffing along at well below maximum power, therefore lower efficiency. With the 3 stage inverter the inverter will power down to a lower size keeping the loading on the inverter at the top of the efficiency curve.
Here's some more info in it

http://www.fronius.com/cps/rde/xchg/SID-989B0CFE-610EC19B/fronius_usa/hs.xsl/2714_9081.htm

[KRenn]

If the array is all at the same tilt, azimuth and no shading issues use the Fronius IG+
And here is the reason
The IG+ is essentially a three stage inverter. meaning it is broken up into essentially 3 4K inverters. Since inverters like to be loaded up to get the most efficiency out of them, other than during the peak hours of the day the inverter will be luffing along at well below maximum power, therefore lower efficiency. With the 3 stage inverter the inverter will power down to a lower size keeping the loading on the inverter at the top of the efficiency curve.
Here's some more info in it

http://www.fronius.com/cps/rde/xchg/.../2714_9081.htm

It's Arizona, Fronius starts to derate performance at about 101 degrees F and continues to do so as the temperature goes up, which means for about 5 months out of the year, your inverter is operating at reduced output. Power-One on the other hand won't derate performance until the temperature touches 120 F ambient, however few times that happens in a year.


Power-One also has the advantage of being rated NEMA4, which is of tremendous importance in Arizona where we often have dust storms that can result in debris ending up inside a lesser-rated inverter. I also believe that the Power-One will start up at a lower input voltage than most of the other central inverters, earlier startup time=more production throughout the year.

I believe that Sun power is recommending Power-One as their primary inverter selection since the Power-One's are higher efficiency and transformerless as well.


"Maximum performance: The panels that make up the new E20 Series are compatible with Transformer-less (TL) Inverters. This means that SunPower superior panel performance can now be matched with the highest performing inverters, maximising system output."

http://www.sunpowercorp.co.uk/homes/products-services/solar-panels/e20/

http://dcpower-systems.com/uploads/products/25366_1.pdf

[Ian S]

It's Arizona, Fronius starts to derate performance at about 101 degrees F and continues to do so as the temperature goes up, which means for about 5 months out of the year, your inverter is operating at reduced output. Power-One on the other hand won't derate performance until the temperature touches 120 F ambient, however few times that happens in a year.


Power-One also has the advantage of being rated NEMA4, which is of tremendous importance in Arizona where we often have dust storms that can result in debris ending up inside a lesser-rated inverter. I also believe that the Power-One will start up at a lower input voltage than most of the other central inverters, earlier startup time=more production throughout the year.

I believe that Sun power is recommending Power-One as their primary inverter selection since the Power-One's are higher efficiency and transformerless as well.


"Maximum performance: The panels that make up the new E20 Series are compatible with Transformer-less (TL) Inverters. This means that SunPower superior panel performance can now be matched with the highest performing inverters, maximising system output."

http://www.sunpowercorp.co.uk/homes/products-services/solar-panels/e20/

http://dcpower-systems.com/uploads/products/25366_1.pdf

I looked up my SP-7000m and it appears to start to derate at 113F. However, by the time it starts to derate, the power from the PV modules will already be well down from full. Still, I suspect that being in a room off my garage, it probably won't be as long lived as I would hope. It like the Fronius is rated NEMA 3R which is not appropriate for dusty conditions. Wish I had the Power one(s).

[KRenn]

I looked up my SP-7000m and it appears to start to derate at 113F. However, by the time it starts to derate, the power from the PV modules will already be well down from full. Still, I suspect that being in a room off my garage, it probably won't be as long lived as I would hope. It like the Fronius is rated NEMA 3R which is not appropriate for dusty conditions. Wish I had the Power one(s).

I don't think Power-One was available when you signed up, the first panel it was compatible with was their newest 327 watt, all their other panels I believe were grounded differently and incompatible with TL inverters.

[josefaz]

It's Arizona, Fronius starts to derate performance at about 101 degrees F and continues to do so as the temperature goes up, which means for about 5 months out of the year, your inverter is operating at reduced output. Power-One on the other hand won't derate performance until the temperature touches 120 F ambient, however few times that happens in a year.


Power-One also has the advantage of being rated NEMA4, which is of tremendous importance in Arizona where we often have dust storms that can result in debris ending up inside a lesser-rated inverter. I also believe that the Power-One will start up at a lower input voltage than most of the other central inverters, earlier startup time=more production throughout the year.

I believe that Sun power is recommending Power-One as their primary inverter selection since the Power-One's are higher efficiency and transformerless as well.


"Maximum performance: The panels that make up the new E20 Series are compatible with Transformer-less (TL) Inverters. This means that SunPower superior panel performance can now be matched with the highest performing inverters, maximising system output."

http://www.sunpowercorp.co.uk/homes/products-services/solar-panels/e20/

http://dcpower-systems.com/uploads/products/25366_1.pdf

Likewise, when I was comparing inverters from different manufacturers, I found the Power One Aurora the best particularly here in the Arizona desert. I'm not sure about the warranty though. The website has some conflicting info about this. The specs sheet shows 5 years but the brochure shows 10 years. Seems the industry standard is 10 years.

About the derating factor, I found a website that sells a kit to help lower the temp in the garage during the summer months. The kit consist of 2 fans, vents, retractable cord and a thermostat. The fan mount to the garage door itself. Something to consider so long as our HOA approves it. I'm still monitoring our garage temp and so far my highest reading is 116 with 2 cars recently parked in the middle of the day.

[Mike90250]

...... About the derating factor, I found a website that sells a kit to help lower the temp in the garage during the summer months. The kit consist of 2 fans, vents, retractable cord and a thermostat. The fan mount to the garage door itself. Something to consider so long as our HOA approves it. I'm still monitoring our garage temp and so far my highest reading is 116 with 2 cars recently parked in the middle of the day.

I just used a shelf in my garage, a cheap desk fan and a plug-in timer.
WiredInverter_c.jpg

You can see in my chart, when the fan turns on, and the heatsink temp drops (Blue line). Could not find a thermostat I'd trust, plug-in timers are everywhere.
5-13Chart.jpg

[Ian S]

I don't think Power-One was available when you signed up, the first panel it was compatible with was their newest 327 watt, all their other panels I believe were grounded differently and incompatible with TL inverters.

OK makes me feel better!

[josefaz]

I just used a shelf in my garage, a cheap desk fan and a plug-in timer.
[ATTACH=CONFIG]2138[/ATTACH]

You can see in my chart, when the fan turns on, and the heatsink temp drops (Blue line). Could not find a thermostat I'd trust, plug-in timers are everywhere.
[ATTACH=CONFIG]2139[/ATTACH]

I guess that's one way to do it but I don't think that will work in Arizona. Circulated air from the outside is needed when the garage door is closed otherwise you're just circulating hotter air in the inverter.