SageBrush
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Location: Colorado

Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:14 am

I just learned about the HD inverters today reading RegGuheert's links.
SolarEdge continues to sell both their HD and non HD inverters, and at similar prices. The only difference I can find so far is that HD do not come in high kW models. Even the warranties are the same. Is this a no-brainer for my 340w * 10 panel system if I choose SE and 400 watt optimizers ?

By the way, the system will be installed in sunny winter colorado at 6300 ft. If any (livable) place can exceed STC, it's my place ! :mrgreen:
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

SageBrush
Posts: 1217
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Location: Colorado

Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:27 am

ltbighorn wrote:
SageBrush wrote:Thanks very much everybody for the input and links.

One more question, if I may: The SE inverters vary little in price from 3.4 to 6.0 kW.
Any downsides to be aware of in oversizing the inverter for the expected production ?


There may be other factors, but at least one is that an inverter is less efficient below certain output levels. For SolarEdge you can find some inverter efficiency charts here:

http://www.solaredge.com/sites/default/ ... ciency.pdf
Thanks, tremendous graphs.

A dumb question about units:
The x axis shows kVA units, but the numbers are from 0 to ~ 3500 (for the 3500 watt inverter)
Is that correct ? My understanding of electricity is pretty mediocre, and does not go much further than volts * amps = watts.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

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RegGuheert
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Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:31 am

SageBrush wrote:I just learned about the HD inverters today reading RegGuheert's links.
SolarEdge continues to sell both their HD and non HD inverters, and at similar prices. The only difference I can find so far is that HD do not come in high kW models. Even the warranties are the same. Is this a no-brainer for my 340w * 10 panel system if I choose SE and 400 watt optimizers ?
I misspoke earlier: Unless your PV modules have more than 60 cells, you are limited to 320W optimizers. If they are 72-cell modules, then definitely go with the 400s. Yeah, if the HD Wave inverters are the same price, I'd definitely buy that. I had assumed they would be more expensive. The performance of those units are simply amazing!
SageBrush wrote:By the way, the system will be installed in sunny winter colorado at 6300 ft. If any (livable) place can exceed STC, it's my place ! :mrgreen:
Yeah, don't purchase S280s for use with 340Wp PV modules. You'd likely lose a bit of production that way. If you go with SolarEdge, get opt for the higher-power optimizers that will work with your PV modules.

Good luck!
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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RegGuheert
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Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:53 am

SageBrush wrote:
ltbighorn wrote:
SageBrush wrote:A dumb question about units:
The x axis shows kVA units, but the numbers are from 0 to ~ 3500 (for the 3500 watt inverter)
Is that correct ? My understanding of electricity is pretty mediocre, and does not go much further than volts * amps = watts.
That's correct and works every time for D.C. power like you get from the panel itself. But the inverter produces AC power and the units for output "power" in AC is known as "VoltAmperes", or VA. That unit means the RMS value of the magnitude of the output power. So, how is that different from Watts? The difference is than in DC power there is no phase angle or any distortion in the waveforms. In AC, there can be both of these things, to the point that if the phase of the current is offset from the phase of the voltage by 90 degrees, no power actually flows. If the phase is more than 90 degrees out, power flows in the opposite direction. There are many different powers which can be calculated in AC systems depending on what you care about. I *think* (without looking it up) the power meter on your house measures the real component of the power which flows (ignoring the imaginary component which just basically just sloshes back and forth and heats up their wires). So, if your inverters do not produce the current in-phase with the voltage, the VA will be higher than the power that is delivered.

Modern solar inverters typically DO produce output current in phase with the voltage waveform, but many, such as the new S280, can be used by the power company to help them correct for problems they have with phase angle. If they do that, the VA out will be higher than the power you get credited for delivering. The efficiency curves will be dictated by the higher VA number.

So, yes, the correct units are VA (or kVA), but in your application, you can just think of kVA as KW and you'll be in good shape.

Aren't you glad you asked? :)
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

SageBrush
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Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:55 am

Thanks, RegGuheert

400 watt optimizers and HD inverter from SolarEdge it is then.
If I'm lucky the solid state components in the SE inverter will be reliable, standardized, and replaceable ...
Nah. Well at least the inverter is not expensive ;-)
Last edited by SageBrush on Fri Jan 27, 2017 10:58 am, edited 1 time in total.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

SageBrush
Posts: 1217
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 10:57 am

RegGuheert wrote:
SageBrush wrote:
ltbighorn wrote:

So, yes, the correct units are VA (or kVA), but in your application, you can just think of kVA as KW and you'll be in good shape.

Aren't you glad you asked? :)
Yes, and thanks for the explanation!

However ...
if the units are kW, shouldn't the scale be from 0 to ~ 3.5 rather than 0 - 3500 ?
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

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RegGuheert
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Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 11:06 am

SageBrush wrote:However ...
if the units are kW, shouldn't the scale be from 0 to ~ 3.5 rather than 0 - 3500 ?
Ha, ha! Is THAT what you were asking?? :oops:

You are correct. SolarEdge has the units wrong on every graph in that document. I didn't notice that. The correct unit is "VA".
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

SageBrush
Posts: 1217
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 11:22 am

RegGuheert wrote:
SageBrush wrote:However ...
if the units are kW, shouldn't the scale be from 0 to ~ 3.5 rather than 0 - 3500 ?
Ha, ha! Is THAT what you were asking?? :oops:

You are correct. SolarEdge has the units wrong on every graph in that document. I didn't notice that. The correct unit is "VA".

Ah, good.

I was afraid that my 8th grade level physics education was for naught :mrgreen:
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Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

wwhitney
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Location: Berkeley, CA

Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 12:10 pm

RegGuheert wrote:Modern solar inverters typically DO produce output current in phase with the voltage waveform, but many, such as the new S280, can be used by the power company to help them correct for problems they have with phase angle. If they do that, the VA out will be higher than the power you get credited for delivering. The efficiency curves will be dictated by the higher VA number.

Hi Reg,

Do you know of any POCOs that are actually doing this? If so, what are the terms for the consumer, do they get credit based on the VA (rather than the reduced Watts), plus a little extra for their trouble?

Cheers,
Wayne

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RegGuheert
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Re: Enphase field MTBF: M190: ~44 Years M215: ~470 Years M250: >275 Years

Fri Jan 27, 2017 4:47 pm

wwhitney wrote:Do you know of any POCOs that are actually doing this?
Not to my knowledge. However, I had thought that Hawaiian Electric would require this with their new laws on January 1, 2016, but it appears they will instead force customers to use storage to keep their generation off the grid. I suppose that is simply more practical because it keeps the lines of control clear: The utility controls their stuff while the customer controls their own.
wwhitney wrote:If so, what are the terms for the consumer, do they get credit based on the VA (rather than the reduced Watts), plus a little extra for their trouble?
I've often wondered the same thing. But I am unsure of one important detail: As the power factor is reduced, does the reactive power simply increase without any loss of what is delivered to the grid, or does the amount of power exported decrease as the power factor is reduced? Or perhaps it does the prior below max inverter output power and the latter once the limit is reached? I simply do not know, but it would make a big difference to me if I were the customer.

Frankly, that's one reason I decided to go ahead an purchase fourth-generation inverters. Then there is no chance of any of that happening with my system. But I'm pretty sure it HAS to happen at some point. It seems there may be a few more hurdles before this comes into practice.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

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