Where's the rest of the cost?

[ButchDeal]

Yeah Butch, I have tossed the idea of the P730 because I have been told by Solaredge Tech Sup the P730 is 3 phase only, I don't see any phasing relationship until the inverter, and their inability to provide answers correctly scares me enough to stay away from that plan.

The electrical parameters with the three panels in series (42vdc 8Amax) each would be within the 125v spec. but there has to be something additional other than electrical parameters.

it is 42.2V for a single PV module. put 3 in series and you would have 126.6V which is by most peoples math, OUTSIDE of the 125V max spec of the optimizer.
Make the PV module a little code and it only gets worse...


The documents for the optimizers specifies that they only work with the 3 phase commercial inverters and lists the models.

the electrical is WAY WAY out of range. you are using different numbers.
a P17-335 pv module has :

1X 3X series
VMPP of 42.2V 126.6V
IMPP of 7.94A 7.94A
VOC of 51.1V 153.3V
ISC of 8.54A 8.54A
wattage 335 1,005 watts

The P730 has an absolute MAX Voltage input (Voc) of 125V < 126.6V
MPPT operating range of 12.5V to 105V < 126.6V
Max Short circuit amp (Isc) of 11A
MAX DC input current of 13.75a
rated input wattage of 730w < 1005 watts of 3 in series

Minimum string length is 8 optimizers on 3 phase 208V inverter which is less than the 6 you would have

This is Before temperature coefficient which will make this worse!

https://us.sunpower.com/sites/sunpower/files/media-library/data-sheets/ds-sunpower-p17-355-commercial-solar-panels.pdf

https://www.solaredge.com/sites/default/files/se-P5-series-commercial-add-on-frame-mounted-power-optimizer-datasheet-na.pdf

[motorcyclemikie]

Yeah I'm ready to roll over. The NEC 2017 RSS 80v spec would preclude attaching two of these 42voc 8A P17 panels together anyway. Three in series will total 126voc 8Asc close enough but not within the RSS spec.

I had trouble getting into the Solaredge design, i'll try it again, thanks guys.

[motorcyclemikie]

Uh, one last brain fart.

The P405 optimizer has almost identical electrical specs as the P730 and Is max at 125voc and 12.6a -- that's over 1500w or +50% over the production of the three series panels. I bet this would work, plus the Solaredge inverter would not know if it is multi phase or single phase DC current, just to end that extra contension point.

Just saying

[ButchDeal]

Uh, one last brain fart.

The P405 optimizer has almost identical electrical specs as the P730 and Is max at 125voc and 12.6a -- that's over 1500w or +50% over the production of the three series panels. I bet this would work,

ok so you are looking at PEAK input limits of 125Voc and 12.6a but the peak OUTPUT on the P703 is 730W and on the P405 is 405W.
The optimizers adjust MPPT to stay within their output limits and have DC to DC buck/boost conversion as well. They the P730 can not output the power from the extreme peak limits of the range of the input which is 1,575w.

The P405 is for thin film PV modules not crystalline.

You can continue to argue that it might but I find it a bit telling that you are no longer willing to put your money on your view of the equipment working in a way that even the manufacturer claims it will not.

plus the Solaredge inverter would not know if it is multi phase or single phase DC current, just to end that extra contension point.

Just saying

The solarEdge inverter and optimizers communicate with each other.
They are computers and they definitely kNOW what equipment they are connected to.

The inverters AND optimizers have minimum string lengths which is strings of optimizers not PV modules which are different per inverter TYPE and optimizer TYPE.
The P730 is designated a Commercial optimizer and as such ONLY works with the commercial 3 phase inverters.

[NukeEngineer]

This is not something to experiment with, unless it's on a house isolated in a desert. Best case scenario, it won't work at all and your money goes up in smoke. Worst case scenario, your house goes up in smoke.

Solaredge has all of the motivation to make their optimizers and inverters as "compatible as possible", to open up as many configurations as possible. If they specifically say "this won't work with that", there's a really really good reason.

[motorcyclemikie]

This is not something to experiment with, unless it's on a house isolated in a desert. Best case scenario, it won't work at all and your money goes up in smoke. Worst case scenario, your house goes up in smoke.


I am in full agreement, I was looking for a "creative" way to bring down the cost of the system.
It's time to visit my local building dept. for permits have a great day!


You know, after rethinking my lack of confidence and questioning the answers (some of which were right) from the support people at Solaredge, I would think that anyone that blindly believes them probably has more money to waste on a over built system than I. My questions may seem redundant here but who better to answer them than the people in the know -- you guys. They use their marketing and misinformation to get at as much of my money as possible, I have to use my common sense to hang onto as much of it as possible.

[azdave]

You know, after rethinking my lack of confidence and questioning the answers (some of which were right) from the support people at Solaredge, I would think that anyone that blindly believes them probably has more money to waste on a over built system than I. My questions may seem redundant here but who better to answer them than the people in the know -- you guys. They use their marketing and misinformation to get at as much of my money as possible, I have to use my common sense to hang onto as much of it as possible.

I have customers that try to use our products in "creative" ways too, thinking they know better and will save money. When the install fails and it costs them big bucks to fix the damage, they get their lawyers involved and come after us looking for any little excuse to say we didn't warn them properly not to use our products in unintended ways. It costs a lot of money in liability insurance premiums each year to protect my company from people who think they know more about our products than we do.

[littleharbor]

[


I am in full agreement, I was looking for a "creative" way to bring down the cost of the system.



Here's some "creative" ways to bring down the cost. Do an energy audit. Replace older less efficient appliances. Replace all lighting with LED lighting. Add extra insulation and caulking to your place. Be conscious of wasteful habits such as leaving lights on unnecessarily, heating/cooling unused space, leaving electronics plugged in 24/7/365 when only used for a fraction of that time.

As far as buying factory second solar panels at a price that isn't much cheaper than A grade panels if you shop around, that could turn out to be a bad decision. Also trying to design a system yourself without sufficient experience could end up costing you more than the price of the equipment.

If you still insist on building your own system based on lowest price then at the very least, educate yourself in system design and be fully aware of the equipment's intended use and limitations.

[J.P.M.]

This is not something to experiment with, unless it's on a house isolated in a desert. Best case scenario, it won't work at all and your money goes up in smoke. Worst case scenario, your house goes up in smoke.


I am in full agreement, I was looking for a "creative" way to bring down the cost of the system.
It's time to visit my local building dept. for permits have a great day!


You know, after rethinking my lack of confidence and questioning the answers (some of which were right) from the support people at Solaredge, I would think that anyone that blindly believes them probably has more money to waste on a over built system than I. My questions may seem redundant here but who better to answer them than the people in the know -- you guys. They use their marketing and misinformation to get at as much of my money as possible, I have to use my common sense to hang onto as much of it as possible.

Reread what littleharbor just wrote. Keep reading it until memorized. Then get educated. Then start thinking long(er) term with a wider scope and past your wallet. Then go to the building dept. and listen more than you talk. Don't buy or do anything else until all that's done.

[motorcyclemikie]

Reread what littleharbor just wrote. Keep reading it until memorized. Then get educated. Then start thinking long(er) term with a wider scope and past your wallet. Then go to the building dept. and listen more than you talk. Don't buy or do anything else until all that's done.

Sure JPM that is the logical approach, I need to maximize my finances on my system. Since I won't be using the gravy (tax credit) that floats this industry I have to be effective with my approach.

Going back to my OP, through my investigation of various designs I see that equipment costs of the PV panels, optimizers, and inverter can be had for less than $.50 a watt.
Example; 250w panels $65ea @$.26w, P800 optimizers $50ea. @$.06w, SE6700H inverter $959 @$.095w
Totals $.45w equipment cost (90% of equipment total)

I want a 5 to 6KWH system,
So @$.45 X 5000w should cost me $2250 plus $225 (10%) for COB I believe it is called. I figure $3000 for 5KWH system would be my target. This figure assumes ideal circumstances with clever designing (example being a system design to actually use the full capacity of all devices: I.E 800w for the P800 optimizer)

Most designs I see are wasteful ,particularly with $/Watt of the optimizers. The best I can get is 750w through the P800, I am fine with that.

My ears are open, I am listening, thanks for your time.

[ButchDeal]

Sure JPM that is the logical approach, I need to maximize my finances on my system. Since I won't be using the gravy (tax credit) that floats this industry I have to be effective with my approach.

Why will you not be using the federal tax credit? do you not pay any federal income tax?

Going back to my OP, through my investigation of various designs I see that equipment costs of the PV panels, optimizers, and inverter can be had for less than $.50 a watt.
Example; 250w panels $65ea, @$.26w P800 optimizers $50ea. @$.06w, SE6700H inverter $959 @$.095w
Totals $.45w equipment cost (90% of equipment total)

The P800 is a commercial optimizer that works with the 3 phase commercial inverters... and they cost more than $50 each
Also it is for two 96 cell PV modules not two 60 cell.

You would want the older P320 optimizers which will work with the SE7600H (there is no SE6700H) and you can likely get them cheap ( or older P300 if you can find them).
You could get an SE5000H or SE6000H cheaper than the SE7600H

You are also going to need rails, flash feet, conduit, AC disconnect, wires, labels, permit (costs money) and an interconnect agreement (often an application fee).

I want a 5 to 6KWH system,

You mean a 5 to 6kW system ...

So @$.45 X 5000w should cost me $2250 plus $225 (10%) for COB I believe it is called. I figure $3000 for 5KWH system would be my target. This figure assumes ideal circumstances

FYI, it is BOD and you are going to need more than $225 for BOD on a 5kW system

You will also need racking and flashing, and standoffs or feet

and again it is not a 5kWH system but a 5kW system

with clever designing (example being a system design to actually use the full capacity of all devices: I.E 800w for the P800 optimizer)

So far you are showing a complete lack of design with little clever to show for it.

My ears are open, I am listening, thanks for your time.

are they though?

https://www.solaredge.com/sites/defa...tasheet-na.pdf

NOTE: even when using these with the 208V small commercial inverters, it is difficult to get the strings to be within all the operating ranges. Even Solaredge admits this limitation with their note #5 on the optimizer spec sheets:

[jflorey2]

I would think that anyone that blindly believes them probably has more money to waste on a over built system than I. My questions may seem redundant here but who better to answer them than the people in the know -- you guys. They use their marketing and misinformation to get at as much of my money as possible, I have to use my common sense to hang onto as much of it as possible.

No one - repeat, no one - wants to waste money on an overbuilt system. There are indeed some unscrupulous people out there who will sell you a cruddy system, but in my experience, the reputable manufacturers (SMA, SolarEdge, Enphase, Outback, Midnite etc) are not among them.

And as other people have mentioned, you are overlooking the balance-of-system costs. Sure, conduit is relatively cheap, as is wire, protection devices, boxes etc. But it adds up. And if you are like most first time installers, you will end up buying 2x of much of that than you need due to inexperience and wastage. (If a solar installer needs two extra lugs he'll go out to his truck and get them. You'll have to drive over to the nearest Graybar and buy a box of 10.)

It can be done - but don't expect it to save you much money over a professional install.

[motorcyclemikie]

Thanks, no I am off the grid so to speak, I have no taxable income subsequently on available tax credit. I am also retired with more time than money so I DIY everything!

The reason the multiphase optimizers produce 85v output (as opposed to the 60v single phase) is for the higher power required for the multiphase output. The SE7600H (sorry about the last mistype) needs 6 sets min. of the higher output optimizers or 8 sets min. of the (P800) lower output optimizers. I chose the P800 so I can attach 3 X 250w panels and still be within ALL specs., (less than 80voc and less than 15Amax , the Trina 250w panels satisfy this @ 12Amax,-- 2 panels in parallel in series with the third )

Again, sorry about the BOD/COB mix up I won't make that mistake again, I have that locked in! I used your 10% SWAG estimate for the BOD, but you will notice I am allowing $500 for it, I realize that is low but one needs a target, anything more is overrun.

I have found new, the P800 optimizers for less the $50 figure that I quoted. (that's gravy against the overrun)

Thanks for your time and knowledge.

I love the forums, on the motorcycle forums I am the hammer like you guys, here I am the nail and I recognize that, please tolerate me with my questions. I am a degreed electrical engineer and always look to ensure everything is logical, this is a sickness I suppose.


You know the 3 X 250w Trina panel configuration is a electrically viable arrangement with the P800, I know the SE7600H is an excellent choice (one is being shipped to me as we speak), I am going to assume it is workable until I hear otherwise from someone that knows from actual experience, otherwise i'll let you know


I remember when Steve Jobs would fire up his apple prototype at the homebrew computer club meetings, first thing out of his mouth was "great it's still working" after a couple times he assumed it was really a viable configuration. I'll do the same until I find out otherwise.

[motorcyclemikie]

Why will you not be using the federal tax credit? do you not pay any federal income tax?



The P800 is a commercial optimizer that works with the 3 phase commercial inverters... and they cost more than $50 each
Also it is for two 96 cell PV modules not two 60 cell.

You would want the older P320 optimizers which will work with the SE7600H (there is no SE6700H) and you can likely get them cheap ( or older P300 if you can find them).
You could get an SE5000H or SE6000H cheaper than the SE7600H

You are also going to need rails, flash feet, conduit, AC disconnect, wires, labels, permit (costs money) and an interconnect agreement (often an application fee).



You mean a 5 to 6kW system ...



FYI, it is BOD and you are going to need more than $225 for BOD on a 5kW system

You will also need racking and flashing, and standoffs or feet

and again it is not a 5kWH system but a 5kW system



So far you are showing a complete lack of design with little clever to show for it.



are they though?

https://www.solaredge.com/sites/defa...tasheet-na.pdf

NOTE: even when using these with the 208V small commercial inverters, it is difficult to get the strings to be within all the operating ranges. Even Solaredge admits this limitation with their note #5 on the optimizer spec sheets:

Yeah, mixing the 85v optimizers with the 60v optimizers would be tricky (note#5) because the available output voltage delta is different between to two but yet they perform the same function -- designing to match the electrical specs of your target inverter (SE7600H in my case) is the critical end result. Solaredge notes specify that string numbers must be maintained (approx 8 strings X 60voc, yet power is regulated by the strings, this allows mismatched string lengths -- I design for this.


The P800 is a commercial optimizer from the aspect of the 800w but it is in the 60voc class this makes it my cholce.

[littleharbor]

B.O.S. = (balance of system). What does BOD stand for?